What are the primary functions of connective tissues?

Provide support, anchor, and connect various parts of the body.

What are the basic structural elements of connective tissues?

Cells and extracellular matrix (fibers and ground substance).

How does connective tissue differ from epithelial tissue in terms of intercellular material?

Connective tissue has more intercellular material, while epithelial tissue has less.

What are the characteristics of loose/areolar connective tissue?

It is very common, supports epithelial tissue, contains numerous fibroblasts and collagen, and is found all over the body where filling material is needed.

What are the components of the extracellular matrix in connective tissues?

Protein fibers and ground substance.

What is the functional unit of both the CNS and PNS?

The neuron.

What are the two components of a dual gland separated by the infundibulum?

An epithelial component (adenohypophysis, anterior lobe, or pars distalis) and a neural component (neurohypophysis, or posterior lobe).

What do the cells in the zona fasciculata secrete?

Glucocorticoids, especially cortisol.

What similarities exist between different types of cartilage?

They can be stained using routine agent staining.

How can elastic cartilage be differentiated from hyaline cartilage?

By using a special stain that highlights elastin, which appears darker in the tissue slide.

What are the two main types of cells in the nervous system?

Neurons and glial cells.

What stimulates aldosterone secretion primarily?

Angiotensin II and an increase in plasma K+ concentration.

What hormones are secreted by the pituitary gland?

Adrenocorticotropic hormone (ACTH), Thyroid-stimulating hormone (TSH), Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Growth hormone (GH), and Prolactin (PRL).

What is the role of the axon in a neuron?

To generate and conduct nerve impulses to other cells.

What does the sensory (afferent) division of the nervous system do?

It carries sensory input perceived consciously or unconsciously.

Where can dense irregular connective tissue be found?

In the dermis of the skin, organ capsules, and the submucosal layer of the gastrointestinal tract.

What is the middle zone of the adrenal cortex called?

Zona Fasciculata.

What are the three main parts of a neuron?

Cell body (perikaryon or soma), dendrites, and axon.

What is the hypothalamic-hypophyseal tract?

A bundle of axons that course into the neurohypophysis from the hypothalamic supraoptic and paraventricular nuclei, through the infundibulum, and into the pars nervosa of the posterior pituitary.

What are the two functional divisions of the nervous system?

Sensory division (afferent) and motor division (efferent).

How is cartilage different from bone in terms of vascularity?

Cartilage is avascular, unlike bone.

What is mesenchyme and what is its significance?

Mesenchyme is a tissue developed mainly from the mesodermal germ layer of the embryo and is the origin of all connective tissues.

What percentage of the adrenal cortex does the zona fasciculata occupy?

65% - 80%.

What is the role of dendrites in a neuron?

To receive stimuli from other neurons at synapses.

What are the effects of cortisol on the body?

It affects carbohydrate metabolism by stimulating gluconeogenesis in many cells and glycogen synthesis in the liver, suppresses many immune functions, and can induce fat mobilization and muscle proteolysis.

What controls cortisol secretion?

ACTH with negative feedback proportional to the concentration of circulating glucocorticoids.

What is the primary function of adipose tissue?

To store neutral fats and regulate the metabolic activity of the body.

What is the main function of the reticular fibers in the adrenal gland's stroma?

Supporting the secretory cells and microvasculature.

What is the key function of skeletal muscles?

Voluntary movements.

How are the cells in most endocrine tissues and organs arranged?

The cells in most endocrine tissues and organs are arranged into cords and clumps and are surrounded by an extensive capillary network.

What structures can be seen in hyaline cartilage?

Lacunae, fibroblasts, and chondroblasts.

What are the types of connective tissues?

Loose/areolar, dense, embryonic, and specialized connective tissues.

What does the neurohypophysis mainly contain?

Neurosecretory axons and their axons, and it functions in storing and releasing the secretory products of the hypothalamus such as Antidiuretic hormone (ADH) and Oxytocin.

What is the location of nuclei in skeletal muscle cells?

Peripheral, adjacent to sarcolemma.

What is the function of releasing hormones?

They stimulate secretion by specific anterior pituitary cells.

What are the characteristic features of steroid-secreting cells in the adrenal cortex?

Acidophilic cytoplasm rich in lipid droplets, with central nuclei.

What role do mitochondria play in steroid hormone synthesis in the adrenal cortex?

They synthesize ATP and contain enzymes for converting cholesterol to pregnenolone and for some steps in steroid synthesis.

What does the central nervous system (CNS) consist of?

The brain and spinal cord.

What type of cells are found in the zona fasciculata?

Long cords of large polyhedral cells, one or two cells thick, separated by fenestrated sinusoidal capillaries.

Where can reticular connective tissue be found?

In bone marrow, liver, adrenal gland, and lymphoid organs.

What do the cells in the zona reticularis secrete?

Primarily weak androgens, including dehydroepiandrosterone (DHEA), which is converted to testosterone in both men and women.

What is the size of motor units in fast, glycolytic fibers (Type IIb)?

Large.

What are myofibrils composed of?

Myofibrils are composed of thick myosin filaments and thin actin filaments.

What is the primary function of dense connective tissue?

To offer stress resistance and protection.

What is a characteristic feature of embryonic connective tissue?

It has abundant ground substance with a 'jelly-like' appearance, sparse collagen fibers, and scattered fibroblasts.

What is the innermost zone of the adrenal cortex called?

Zona Reticularis.

What is the control of contraction in skeletal muscle?

Troponin C binds Ca2+, moving tropomyosin and exposing actin for myosin binding.

Give an example of a hormone that affects the anterior pituitary from outside the feedback loop.

Ghrelin, which acts as a releasing hormone for somatotropin secretion.

What surrounds every muscle fiber?

A basal lamina called the endomysium.

What are the two major divisions of the nervous system?

Central nervous system (CNS) and peripheral nervous system (PNS).

What does the peripheral nervous system (PNS) consist of?

Cranial, spinal, and peripheral nerves, as well as ganglia.

What are the three parts of the adenohypophysis?

The large pars distalis or anterior lobe, the pars tuberalis which wraps around the infundibulum, and the thin pars intermedia adjacent to the posterior pars nervosa.

Where are ADH and Oxytocin synthesized?

ADH is synthesized by large neurons in the supraoptic nuclei and Oxytocin in the paraventricular nuclei.

What do the superior hypophyseal arteries supply?

They supply the median eminence and the infundibular stalk, and divide into a primary plexus of fenestrated capillaries.

What is the function of the hypothalamic-hypophyseal portal system?

It carries neuropeptides from the median eminence to the pars distalis, consisting of two capillary networks connected by the hypophyseal portal vein.

Where can adipose tissue be found?

In subcutaneous fat, omentum, mesentery, inguinal, axillary, and cervical regions.

What does somatostatin inhibit?

It inhibits the release of somatotropin (GH) and TSH.

What is the function of growth hormone-releasing hormone (GHRH)?

It stimulates the release of growth hormone (GH).

What do acidophils secrete and what are they called?

Acidophils secrete either growth hormone (somatotropin) or prolactin (PRL) and are called somatotrophs and lactotrophs, respectively.

What are the characteristics of secretory neurons in the posterior pituitary?

They have large-diameter axons and well-developed synthetic components for producing hormones like ADH and oxytocin.

What are the three types of muscle tissue?

Skeletal muscle, cardiac muscle, and smooth muscle.

What are the three types of cartilage in the body?

Hyaline, Elastic, and Fibrocartilage.

How does dense connective tissue differ from areolar tissue?

Dense connective tissue contains fewer cells and has a predominance of fiber elements over cells and ground substance.

Where can dense regular connective tissue be found?

In ligaments, tendons, and aponeuroses.

What is the primary role of glial cells?

To support neuronal survival and activities.

How are T tubules organized in skeletal muscle cells?

In the center of triads at A-I junctions.

What are the dimensions and weight of the adrenal glands in adults?

About 4-6 cm long, 1-2 cm wide, and 4-6 mm thick, weighing approximately 8 g.

What type of cells are found in the zona reticularis?

Smaller cells in a network of irregular cords interspersed with wide capillaries.

What is the capacity for regeneration in skeletal muscles?

Limited, involving satellite cells mainly.

What is the primary function of the endocrine system?

The endocrine system consists of cells, tissues, and organs that synthesize and secrete hormones directly into blood and lymph capillaries.

Why are endocrine glands ductless?

Endocrine glands are ductless because they do not have excretory ducts.

What is the function of mineralocorticoids produced in the zona glomerulosa of the adrenal cortex?

They affect the uptake of Na+, K+, and water by cells of renal tubules. The principal product is aldosterone, which regulates salt balance.

What are the main components of the pars distalis?

Cords of well-stained endocrine cells interspersed with fenestrated capillaries and supporting reticular connective tissue.

What are the cytoplasmic contractile elements within the sarcoplasm called?

Myofilaments.

What is the role of chondroblasts in cartilage?

Secreting fibers and ground substance.

How can fibrocartilage be identified?

Using a special stain that shows numerous collagen fibers, typically with a specialized blue stain.

What is a key characteristic of dense irregular connective tissue?

Collagen fiber bundles appear randomly interwoven without definite orientation.

What are some examples of specialized connective tissues?

Reticular, adipose, bone, blood, and cartilage.

How is the adrenal medulla supplied with blood?

It has a dual blood supply: arterial blood from the medullary arterioles and venous blood from the cortical capillaries.

What is the term 'fiber' used to contrast in muscle tissue?

It contrasts with connective tissue fiber, which is noncellular, and nerve fiber, which is a cell process.

What is the cytoplasm of a muscle fiber called?

Sarcoplasm.

What are the main types of connective tissues mentioned?

Bone, Blood, Cartilage, Brown Adipose Tissue, White Adipose Tissue.

What is the choroid plexus and its function?

It consists of vascularized pia mater covered by ependyma that projects from the walls of the cerebral ventricles, where water is removed from capillaries and transferred into the ventricles as CSF.

What is the origin and main function of oligodendrocytes?

Origin: Neural tube. Main function: Myelin production and electrical insulation in the CNS.

What is a distinguishing feature of fibrocartilage under special staining?

Numerous collagen fibers visible with a specialized blue stain.

How do collagen fiber bundles appear in dense regular connective tissue?

They appear in a definite pattern with fibers and fibroblasts aligned parallel to resist prolonged and repeated stress exerted in the same direction.

Where can embryonic connective tissue be found?

In Wharton's Jelly (umbilical cord) and dental pulp.

What does the motor (efferent) division of the nervous system do?

It carries motor output controlled consciously or unconsciously.

What is the role of negative feedback in hormone regulation?

It controls the activity of anterior pituitary cells by hormones from target organs on the secretion of hypothalamic factors and pituitary hormones.

Where is brown adipose tissue primarily located in newborns?

Mainly in the back, neck, and shoulders.

From where is the epithelial component of the hypophyseal pouch derived?

It is derived from an outpocketing of ectoderm from the roof of the primitive mouth.

What are reticular fibers made of in reticular connective tissue?

Type III collagen with attached specialized fibroblasts called reticular cells.

Where are the adrenal glands located?

Near the superior poles of the kidneys, embedded in the pararenal adipose tissue and fascia.

What is the major source of ATP for slow, oxidative fibers (Type I)?

Oxidative phosphorylation.

What is the rate of fatigue for fast, glycolytic fibers (Type IIb)?

High.

What is the typical major location for slow, oxidative fibers (Type I)?

Postural muscles of the back.

What are the three parts of the adenohypophysis derived from embryonically?

The hypophyseal pouch.

How are cardiac muscle fibers linked?

Cardiac muscle fibers are linked by adherent and gap junctions at intercalated discs.

What special staining technique is used to differentiate elastic cartilage from hyaline cartilage?

Elastic staining, which visualizes elastic fibers.

What distinguishes dense regular connective tissue from dense irregular connective tissue?

Dense regular connective tissue has fibers arranged in parallel, while dense irregular connective tissue has fibers arranged in a random or irregular pattern.

What role does the interstitial fluid of connective tissue play?

It provides metabolic support to cells as the medium for diffusion of nutrients and waste products.

What are the two concentric regions of the adrenal glands?

The yellowish adrenal cortex and the reddish-brown central adrenal medulla.

From which embryonic origins do the adrenal cortex and medulla arise?

The cortex arises from the mesoderm, and the medulla arises from the neural crest.

What is the unit of muscle tissue called?

A cell, often referred to as a muscle fiber.

What is the pars tuberalis and what type of cells does it mostly contain?

A smaller funnel-shaped region surrounding the infundibulum of the neurohypophysis, mostly containing gonadotrophs.

What constitutes the blood-brain barrier?

The perivascular feet of astrocytic processes and the nonfenestrated capillary endothelial cells' tight junctions.

What are groups of muscle fibers called and what surrounds them?

Groups of muscle fibers are called fascicles and are surrounded by perimysium.

What are the basic properties shared by all muscle types?

Conductivity, irritability, contractility, relaxation, distensibility, and elasticity.

What type of connective tissue organization is found in skeletal muscles?

Endomysium, perimysium, and epimysium.

What is the function of thyrotropin-releasing hormone (TRH)?

It stimulates the release of thyrotropin (TSH).

What percentage of the adenohypophysis does the pars distalis account for?

75%

What are the two broad groups of cells in the pars distalis based on staining affinities?

Chromophils and chromophobes.

How are muscles classified based on morphology?

Based on the presence or absence of striations: striated or smooth (non-striated).

What is the main protein synthesized in corticotrophs and what does it cleave into?

Pro-opiomelanocortin (POMC), which cleaves into adrenocortical trophic hormone (ACTH) and β-lipotropin (β-LPH).

What is the function of vasopressin/antidiuretic hormone (ADH)?

It increases water permeability of renal collecting ducts and is released in response to increased blood tonicity.

What is the shape and size of cardiac muscle fibers?

Cylindrical, 10-20 μm in diameter, 50-100 μm long.

Name the two types of glial cells in the PNS.

Satellite Cells and Schwann Cells (Neurolemmocytes).

What happens during endochondral ossification?

A pre-existing matrix of cartilage is eroded and invaded by osteoblasts, which then begin osteoid production.

What are the predominant cells and fibers in adipose tissue?

The predominant cells are adipocytes (fat cells), and the predominant fibers are reticular and collagen fibers.

What stimulates secretion in the zona reticularis?

ACTH with regulatory feedback.

What do inhibiting hormones do?

They block hormone secretion in specific cells of the adenohypophysis.

How do steroid hormones differ from protein hormones in terms of storage and release?

Steroid hormones are not stored in granules nor undergo exocytosis; they diffuse freely through the plasma membrane.

What types of molecules are hormones often, and how are they distributed in the body?

Hormones are frequently hydrophilic molecules such as proteins, glycoproteins, peptides, or modified amino acids with receptors on the surface of target cells. Hydrophobic steroid and thyroid hormones must circulate on transport proteins but can diffuse through cell membranes and activate cytoplasmic receptors in target cells.

What is the neurohypophysis composed of?

It is composed of neural tissue containing unmyelinated axons of large secretory neurons from the hypothalamus.

What are the characteristics of cardiac muscle?

Has cross-striations, composed of elongated, often branched cells bound at intercalated discs; contraction is involuntary, vigorous, and rhythmic.

Name the four types of glial cells in the CNS.

Oligodendrocytes, Astrocytes, Ependymal Cells, and Microglial Cells.

What do satellite cells in ganglia do?

Provide structural and metabolic support for neuronal cell bodies.

How does nervous tissue develop in the early embryo?

The dorsal ectoderm neural plate folds to form the neural tube, precursor of the CNS, and releases neural crest cells, precursors for much of the PNS.

What happens during intramembranous ossification?

Osteoblasts differentiate directly from the mesenchyme and begin creating osteoid.

What percentage of the adrenal cortex does the zona reticularis comprise?

About 10%.

What is the basic function of muscles?

To generate force (propulsion) to make locomotion possible.

What are some examples of mixed (endocrine-exocrine) organs?

Examples of mixed organs include the pancreas, kidneys, reproductive organs of both sexes, placenta, and gastrointestinal tract.

What is the structure of endocrine glands compared to exocrine glands?

The structure of endocrine glands is much simpler, usually consisting of a capsule, connective tissue, and the parenchyma consisting of networks of reticular fibers.

What is paracrine secretion?

Paracrine secretion involves localized dispersal in interstitial fluid or through short loops of blood vessels, as when gastrin made by pyloric G cells reaches target cells in the fundic glands.

What are the three connective tissue layers that enclose the CNS called?

Meninges: dura mater, arachnoid layer, and pia mater.

What gives brown adipose tissue its color?

The very abundant mitochondria and the larger number of blood capillaries.

What is the principal function of brown adipose tissue?

Heat production and warming the blood.

What shape are white adipocytes when isolated and when closely packed?

Spherical when isolated and polyhedral when closely packed.

What are white adipocytes also called due to their single large droplet of triglycerides?

Unilocular.

What is the role of satellite cells in the PNS?

Satellite cells electrically insulate PNS cell bodies and regulate their microenvironment.

What are the two processes of osteogenesis?

Intramembranous and Endochondral ossification.

What distinguishes microglia from other glial cells?

Microglia originate from blood monocytes, not neural tissue precursors, and mediate immune defense activity within the CNS.

How does skeletal muscle regenerate?

Skeletal muscle can regenerate due to reserve muscle satellite cells that can proliferate, fuse, and form new muscle fibers.

What are muscles in the human body?

Bands or bundles of fibrous tissues that generate force for locomotion and provide shape and form to the organism.

What hormones are released due to gonadotropin-releasing hormone (GnRH)?

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

What is the role of dopamine in hormone regulation?

It inhibits the release of prolactin (PRL).

What are the target cells of basophilic cells in the pars distalis?

Adrenal cortex, gonads, and thyroid gland.

What are the characteristics of skeletal muscle?

Contains bundles of very long, multinucleated cells with cross striations; contraction is quick, forceful, and usually under voluntary control.

What are glial cells and where are they found?

Glial cells support neurons and are found in both the CNS and PNS.

What is the function of oligodendrocytes?

Oligodendrocytes myelinate and insulate CNS axons.

What is the primary function of microglial cells?

Microglial cells protect the CNS by engulfing infectious agents and harmful substances.

What is the main function of Schwann cells?

Myelin production and electrical insulation in peripheral nerves.

What do peripheral nerves consist of?

Axons from motor neurons, sensory neurons, and autonomic neurons, all enclosed within a series of Schwann cells.

What are the main components of a neuron?

A neuron consists of a cell body (perikaryon), an axon, and one or more dendrites.

What is a synapse?

A synapse is a junction where a neurotransmitter is released at the presynaptic membrane and binds receptors on the postsynaptic cell, initiating a new action potential.

What is unique about the filaments in smooth muscle fibers?

Thin and thick filaments in smooth muscle fibers do not form sarcomeres and there are no striations.

What type of efferent innervation do skeletal muscles have?

Motor.

What hormones do gonadotrophs secrete?

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

Which meningeal layer directly contacts neural tissue?

Pia mater.

What are brown adipocytes called due to their many small lipid inclusions?

Multi-globular.

What is white adipose tissue specialized for?

Relatively long-term energy storage.

What is the function of ependymal cells?

Aid production and movement of CSF.

What is the function of Schwann cells?

Schwann cells surround and insulate PNS axons and myelinate those with large diameters.

What do canaliculi contain?

Blood vessels.

Why is regeneration and restoration of function difficult in the CNS after major injury?

Due to the complexity and distances of the neuronal and glial interconnections.

What is the plasma membrane of a muscle fiber called?

The sarcolemma.

What is autocrine secretion?

Autocrine secretion occurs when cells produce molecules that act on themselves or on cells of the same type, such as insulin-like growth factor (IGF) produced by several cell types that may act on the same cells that produced it.

Why is the pituitary gland referred to as the 'master' gland?

The pituitary gland is called the 'master' gland because it controls many bodily functions, although it is only a link in the body’s neuroendocrine system.

What is the function of the arachnoid layer in the CNS?

It contains much CSF, which helps cushion the CNS within its bony enclosure.

What do corticotrophs of the pars intermedia produce and what is their main function?

They produce smaller peptide hormones, including two forms of melanocyte-stimulating hormone (MSH), γ-LPH, and β-endorphin; MSH increases melanocyte activity.

What are the main functions of astrocytes?

Structural and metabolic support of neurons, especially at synapses; repair processes.

What is the origin and function of microglia?

Origin: Bone marrow (monocyte). Function: Defense and immune-related activities in the CNS.

What is endoneurium?

A thin connective tissue layer immediately surrounding Schwann cells in peripheral nerves.

What causes the myosin heads to bind to actin subunits?

Ca2+ binding to troponin causes tropomyosin to change shape, allowing myosin heads to bind to actin subunits.

What process allows better capacity for axonal regeneration in peripheral nerves?

A process involving reactivation of the perikaryon, Schwann cells, and macrophages.

What allows smooth muscle cells to contract?

Thin actin filaments attach to α-actinin in dense bodies, causing cells to shorten individually during contraction.

What is juxtacrine secretion and why is it important?

Juxtacrine secretion involves a signaling molecule that remains on the secreting cell’s surface or adjacent extracellular matrix and affects target cells when the cells make contact. It is particularly important in embryonic and regenerative tissue interactions.

How are muscles classified based on function?

Based on whether they are voluntary or involuntary.

Where is brown adipose tissue found in adults?

Around the kidneys, adrenal glands, aorta, and mediastine.

What is the shape and size of smooth muscle fibers?

Fusiform, 0.2-10 μm in diameter, 50-200 μm long.

What is the size range of a fully developed white adipocyte?

Between 50 to 150 micrometers in diameter.

What is the perineurium?

A layer consisting of squamous fibroblastic cells joined by tight junctions, forming a blood-nerve barrier.

What does the extracellular matrix of cartilage contain?

Collagen and elastic fibers.

What are pituicytes?

Highly branched glial cells resembling astrocytes, abundant in the posterior pituitary.

Where is the pituitary gland located?

The pituitary gland lies below the brain in a small cavity on the sphenoid bone called the sella turcica.

What are chromophobes and what do they represent?

Chromophobes stain weakly, with few or no secretory granules, and represent a heterogeneous group, including stem and undifferentiated progenitor cells as well as any degranulated cells present.

What are the characteristics of smooth muscle?

Consists of collections of fusiform cells that lack striations and have slow, involuntary contractions.

What is the function of the sarcoplasmic reticulum (SR) in muscle cells?

The sarcoplasmic reticulum is specialized for Ca2+ sequestration and release.

What are osteocytes and where are they found?

Osteocytes are bone cells trapped in lacunae.

What is the epineurium?

A thick, outermost layer of dense irregular connective tissue surrounding the perineurium.

What ends muscle contraction?

Muscle contraction ends when Ca2+ is sequestered again and the sarcomeres lengthen.

What are pyramidal neurons and where are they found?

Pyramidal neurons are layers of small neurons that form the cerebral cortex.

How is the contraction of cardiac muscle regulated?

Contraction is intrinsic at nodes of pacemaker muscle fibers, regulated by autonomic nerves.

What does corticotropin-releasing hormone (CRH) stimulate?

It stimulates the synthesis of pro-opiomelanocortin (POMC) and the release of β-lipotropic hormone (β-LPH) and corticotropin (ACTH).

What is the approximate weight and dimensions of the pituitary gland in adults?

The pituitary gland weighs about 0.5 g in adults and has dimensions of about 10 × 13 × 6 mm.

What are neurosecretory bodies or Herring bodies?

Axonal dilations containing granules with oxytocin or ADH bound to neurophysins.

What are the functions of hormones produced by the pars distalis?

Regulate almost all other endocrine glands, ovarian function and sperm production, milk production, and metabolism of muscle, bone, and adipose tissue.

What is the pars intermedia and what does it contain?

A narrow zone lying between the pars distalis and the pars nervosa, containing basophils (corticotrophs), chromophobes, and small, colloid-filled cysts derived from the lumen of the embryonic hypophyseal pouch.

How do hypothalamic hormones control the activities of the anterior pituitary?

They are produced by small neurons near the third ventricle, discharged from axons in the median eminence, and transported by capillaries of the portal system throughout the anterior pituitary.

What encloses all fascicles in skeletal muscle?

A dense connective tissue called epimysium.

What triggers the release of Ca2+ in muscle cells?

Depolarization of the sarcolemma triggers Ca2+ release.

What are synapses of motor axons with skeletal muscle called?

They are called motor end plates (MEPs), neuromuscular junctions (NMJs), or myoneural junctions.

Why does cardiac muscle have little capacity for regeneration?

Cardiac muscle lacks satellite cells.

What are the functions of oxytocin?

It stimulates contraction of mammary gland myoepithelial cells and uterine smooth muscle, and promotes pair-bonding behavior.

What is the shape and size of skeletal muscle fibers?

Cylindrical, 10-100 μm in diameter, many cm long.

What separates sarcomeres?

Sarcomeres are separated by Z discs.

What is the neurotransmitter used at neuromuscular junctions?

The neurotransmitter is acetylcholine.

What are sarcomeres?

Sarcomeres are contractile units within myofibrils where thick and thin filaments interdigitate.

What allows some replacement of neurons throughout life in certain CNS regions?

Neural stem and progenitor cells.

What are muscle spindles and tendon organs?

They are sensory proprioceptors with sensory axons wrapping around intrafusal fibers or myotendinous collagen bundles.

What role do astrocytes play in the CNS?

Astrocytes provide structural support and organization to the CNS.

What do ependymal cells do?

Ependymal cells line the ventricles of the brain and central canal of the spinal cord.

What is the hardest connective tissue?

Bone.

What forms a triad in muscle cells?

Two terminal cisterns of SR and a transverse (T) tubule form a triad.

How do neurons transmit nerve impulses?

Neurons use excitability to produce and move an action potential along the axon to excite another neuron or effector cell.

What do ganglia contain?

Neuronal cell bodies and their satellite cells, surrounded by connective tissue continuous with that of nerves.

What are Purkinje neurons and where are they found?

Purkinje neurons are large, unique neurons that characterize the cortex of the cerebellum.

What allows for rapid regeneration in smooth muscle?

Smooth muscle cells are small and less differentiated, allowing for renewed mitotic activity after injury.

Why do unilocular adipocytes often appear empty in standard light microscopy?

Because lipid is removed from the cells by xylene or other solvents used in routine histological techniques.

What are the functions of bone?

Protecting body organs and providing support for skeletal muscles.

What happens when myosin heads pivot with ATP hydrolysis?

The thin filaments are pulled along the thick filaments, causing contraction.

What is the difference between gray matter and white matter in the CNS?

Gray matter is rich in neuronal perikarya and astrocytes, while white matter contains tracts of myelinated axons.

What are chondrocytes?

Mature chondroblasts isolated in lacunae.

What are the two concentric regions of the adrenal gland?

A) Adrenal cortex and adrenal medulla

B) Adrenal cortex and adrenal capsule

C) Adrenal medulla and adrenal capsule

D) Adrenal cortex and adrenal stroma

E) Adrenal medulla and adrenal stroma

Which division of the nervous system includes the brain and spinal cord?

A) Peripheral nervous system

B) Central nervous system

C) Autonomic nervous system

D) Somatic nervous system

E) Sensory nervous system

Which of the following organs is a mixed (endocrine-exocrine) organ?

A) Thyroid gland

B) Adrenal gland

C) Pancreas

D) Pineal gland

E) Parathyroid gland

Which hormone is released in response to increased blood tonicity?

A) Oxytocin

B) Dopamine

C) Corticotropin-releasing hormone (CRH)

D) Antidiuretic hormone (ADH)

E) Growth hormone-releasing hormone (GHRH)

Where are the adrenal glands located?

A) Near the inferior poles of the kidneys

B) Near the superior poles of the kidneys

C) In the brain

D) In the liver

E) Near the heart

What is the sensory division of the nervous system responsible for?

A) Conducting motor output to muscles

B) Generating nerve impulses

C) Receiving sensory input

D) Supporting neuronal activities

E) Protecting neurons

What is a characteristic feature of mesenchyme?

A) High density of collagen fibers

B) Absence of ground substance

C) Consists largely of viscous ground substance with few collagen fibers

D) High concentration of adipocytes

E) Predominantly composed of epithelial cells

What is the role of hypothalamic hormones in the anterior pituitary?

A) To stimulate the release of digestive enzymes

B) To control the activities of the cells of the anterior pituitary

C) To regulate blood pressure

D) To produce neurotransmitters

E) To inhibit the release of insulin

Which glial cell type electrically insulates PNS cell bodies?

A) Oligodendrocyte

B) Schwann Cell

C) Microglial Cell

D) Satellite Cell

E) Astrocyte

Which layer of the meninges directly contacts neural tissue?

A) Dura mater

B) Arachnoid layer

C) Pia mater

D) Choroid plexus

E) Endoneurium

From which embryonic origins do the adrenal cortex and medulla arise?

A) Cortex from endoderm, medulla from ectoderm

B) Cortex from ectoderm, medulla from mesoderm

C) Cortex from mesoderm, medulla from neural crest

D) Cortex from neural crest, medulla from mesoderm

E) Both from mesoderm

What is a characteristic feature of cells in the adrenal cortex?

A) Basophilic cytoplasm

B) Acidophilic cytoplasm rich in lipid droplets

C) Lack of mitochondria

D) Presence of large granules

E) Absence of smooth ER

What type of secretion involves localized dispersal in interstitial fluid or through short loops of blood vessels?

A) Autocrine secretion

B) Juxtacrine secretion

C) Paracrine secretion

D) Endocrine secretion

E) Exocrine secretion

What is the primary function of connective tissues?

A) To form a protective barrier

B) To provide support, anchor, and connect various parts of the body

C) To facilitate movement

D) To conduct electrical impulses

E) To produce hormones

What are the basic structural elements of connective tissues?

A) Cells and extracellular matrix

B) Cells and blood vessels

C) Cells and nerves

D) Cells and muscle fibers

E) Cells and epithelial layers

What is the primary function of the mineralocorticoids produced in the zona glomerulosa?

A) Regulate blood sugar levels

B) Affect uptake of Na+, K+, and water by cells of renal tubules

C) Stimulate the immune system

D) Regulate reproductive hormones

E) Control stress responses

What percentage of the adrenal cortex does the zona fasciculata occupy?

A) 10%

B) 20%

C) 30%

D) 50%

E) 65% - 80%

Which hormone is primarily secreted by the cells of the zona fasciculata?

A) Aldosterone

B) Cortisol

C) Testosterone

D) Insulin

E) Epinephrine

What is the primary secretion of the cells in the zona reticularis?

A) Aldosterone

B) Cortisol

C) Insulin

D) Weak androgens like dehydroepiandrosterone (DHEA)

E) Epinephrine

Which type of hormone is frequently hydrophilic and has receptors on the surface of target cells?

A) Steroid hormones

B) Thyroid hormones

C) Proteins, glycoproteins, peptides, or modified amino acids

D) Fatty acids

E) Lipids

What is the basic function of muscle tissue?

A) To store energy

B) To generate force for locomotion

C) To transport nutrients

D) To produce hormones

E) To protect internal organs

What is the main function of cortisol secreted by the zona fasciculata?

A) Stimulates insulin secretion

B) Increases blood pressure

C) Affects carbohydrate metabolism by stimulating gluconeogenesis and glycogen synthesis in the liver

D) Increases heart rate

E) Enhances bone growth

What structure surrounds groups of muscle fibers called fascicles?

A) Epimysium

B) Endomysium

C) Perimysium

D) Sarcolemma

E) Sarcoplasmic reticulum

Which muscle type has striations and peripheral nuclei?

A) Skeletal muscle

B) Cardiac muscle

C) Smooth muscle

D) All muscle types

E) None of the above

What is a characteristic of embryonic connective tissue?

A) High fiber content

B) Sparse ground substance

C) Jelly-like appearance with abundant ground substance

D) Predominance of adipocytes

E) High metabolic activity

What are the two components of the dual gland separated by the infundibulum?

A) Adenohypophysis and neurohypophysis

B) Thyroid and parathyroid

C) Adrenal cortex and adrenal medulla

D) Pineal gland and pituitary gland

E) Pancreas and liver

Which of the following glial cells is responsible for myelinating and insulating CNS axons?

A) Astrocyte

B) Ependymal Cell

C) Microglial Cell

D) Oligodendrocyte

E) Satellite Cell

How can you differentiate elastic cartilage from hyaline cartilage using staining?

A) By using routine agent staining

B) By using elastic staining to visualize elastic fibers

C) By using blue staining to see collagen fibers

D) By observing the shape of cells

E) By measuring the thickness of the cartilage

What is the primary function of neurons in the nervous system?

A) To provide structural support

B) To generate and conduct nerve impulses

C) To produce hormones

D) To store nutrients

E) To protect against infections

What is the main role of glial cells in the nervous system?

A) To conduct nerve impulses

B) To support and protect neurons

C) To generate muscle contractions

D) To produce sensory input

E) To form synapses

Which of the following is NOT a characteristic of epithelial tissue compared to connective tissue?

A) Less intercellular material

B) Cells are closely packed together

C) Presence of ground substance

D) Provides a lining surface

E) Lacks fibers interspersed among cells

Which type of connective tissue is very common in the body and supports epithelial tissue?

A) Dense connective tissue

B) Reticular connective tissue

C) Loose/areolar connective tissue

D) Cartilage

E) Bone

What are the contractile units within myofibrils called?

A) Sarcolemma

B) Sarcoplasmic reticulum

C) Sarcomeres

D) Myosin heads

E) Z discs

Which of the following is NOT a type of cartilage found in the body?

A) Hyaline

B) Elastic

C) Fibrocartilage

D) Osteocartilage

E) All of the above are types of cartilage

Which of the following is true about the pituitary gland?

A) It is located in the abdominal cavity

B) It weighs about 5 grams in adults

C) It lies below the brain in a small cavity on the sphenoid bone

D) It is not involved in the neuroendocrine system

E) It is also known as the adrenal gland

Which hormone stimulates the release of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH)?

A) Thyrotropin-releasing hormone (TRH)

B) Corticotropin-releasing hormone (CRH)

C) Gonadotropin-releasing hormone (GnRH)

D) Growth hormone-releasing hormone (GHRH)

E) Dopamine

What is the primary function of oxytocin?

A) Increases water permeability of renal collecting ducts

B) Inhibits the release of prolactin (PRL)

C) Stimulates contraction of mammary gland myoepithelial cells and uterine smooth muscle

D) Stimulates the release of thyrotropin (TSH)

E) Inhibits the release of somatotropin (GH)

What gives brown adipose tissue its color?

A) Presence of collagen fibers

B) High lipid content

C) Abundant mitochondria and blood capillaries

D) High water content

E) Presence of chondrocytes

What does the hypothalamic-hypophyseal portal system consist of?

A) Two capillary networks connected by the hypophyseal portal vein

B) A single capillary network

C) A network of veins only

D) A network of arteries only

E) A network of lymphatic vessels

What is the hardest connective tissue?

A) Cartilage

B) Blood

C) Bone

D) Adipose tissue

E) Ligament

Which of the following is NOT a characteristic of endocrine glands?

A) They have excretory ducts

B) They are ductless

C) They have a rich blood supply

D) They consist of a capsule, connective tissue, and parenchyma

E) They are usually simpler in structure compared to exocrine glands

From which embryonic layer do most connective tissues originate?

A) Ectoderm

B) Endoderm

C) Mesoderm

D) Neural crest

E) Epiblast

Which type of muscle tissue is characterized by long, multinucleated cells with cross striations?

A) Smooth muscle

B) Cardiac muscle

C) Skeletal muscle

D) Nervous tissue

E) Epithelial tissue

What is the predominant cell type in adipose tissue?

A) Fibroblasts

B) Chondrocytes

C) Osteocytes

D) Adipocytes

E) Reticular cells

What is intramembranous ossification?

A) The process of cartilage formation

B) Osteoblasts differentiate directly from mesenchyme and create osteoid

C) The conversion of brown adipose tissue to white adipose tissue

D) The formation of blood vessels in bone

E) The secretion of fibers and ground substance by chondroblasts

What are chondrocytes?

A) Immature bone cells

B) Mature chondroblasts isolated in lacunae

C) Blood cells

D) Cells found in the epidermis

E) Muscle cells

What is a key characteristic of cartilage that differentiates it from bone?

A) It is vascular

B) It is avascular

C) It contains blood vessels

D) It is harder than bone

E) It is more flexible than bone

Which part of a neuron is specialized to receive stimuli from other neurons?

A) Axon

B) Cell body

C) Dendrites

D) Neurolemma

E) Synapse

What is the unique structure found in cardiac muscle cells?

A) Endomysium

B) Sarcolemma

C) Intercalated discs

D) Myofilaments

E) Sarcoplasmic reticulum

What is the location of T tubules in cardiac muscle?

A) At the center of triads at A-I junctions

B) In dyads at Z discs

C) Absent; caveolae may be functionally similar

D) At the neuromuscular junction

E) At the center of triads at H zone

How are muscles classified based on morphology?

A) Striated or smooth

B) Voluntary or involuntary

C) Fast-twitch or slow-twitch

D) Large or small

E) Single or multinucleated

Which muscle type is described as having cylindrical cells with a diameter of 10-20 μm and a length of 50-100 μm?

A) Skeletal muscle

B) Cardiac muscle

C) Smooth muscle

D) Nervous tissue

E) Connective tissue

What is the special name given to the cytoplasm of muscle fibers?

A) Sarcolemma

B) Sarcoplasm

C) Endomysium

D) Myofilament

E) Sarcoplasmic reticulum

Which part of the neurohypophysis retains many histologic features of brain tissue?

A) Pars distalis

B) Pars tuberalis

C) Pars intermedia

D) Pars nervosa

E) Pars anterior

Which of the following is NOT a part of a typical neuron?

A) Dendrites

B) Axon

C) Glial cells

D) Cell body

E) Synapse

What is the main difference between the somatic and autonomic motor divisions?

A) Somatic is controlled voluntarily, autonomic is not

B) Somatic controls glands, autonomic controls muscles

C) Somatic is part of the CNS, autonomic is part of the PNS

D) Somatic generates sensory input, autonomic generates motor output

E) Somatic involves glial cells, autonomic involves neurons

Which of the following is NOT a type of connective tissue?

A) Bone

B) Blood

C) Cartilage

D) Muscle

E) Reticular

Which characteristic is shared by all muscle types?

A) Conductivity

B) Striations

C) Peripheral nuclei

D) High glycogen content

E) Large fiber diameter

What is the primary function of astrocytes in the CNS?

A) Myelinate axons

B) Provide structural support and organization

C) Line ventricles of the brain

D) Protect CNS by engulfing infectious agents

E) Insulate PNS axons

Which cells are involved in the blood-brain barrier?

A) Schwann cells and satellite cells

B) Astrocytic processes and nonfenestrated capillary endothelial cells

C) Oligodendrocytes and microglia

D) Ependymal cells and choroid plexus

E) Perineurium and epineurium

What is the role of the perineurium in peripheral nerves?

A) Surrounding Schwann cells

B) Forming the blood-nerve barrier

C) Surrounding neuronal cell bodies

D) Providing structural support

E) Producing myelin

What primarily stimulates aldosterone secretion?

A) ACTH

B) Angiotensin II

C) Increased plasma Na+ concentration

D) Decreased plasma K+ concentration

E) Insulin

What special staining is used to differentiate fibrocartilage?

A) Elastic staining

B) Routine agent staining

C) Blue staining to visualize collagen fibers

D) Red staining to visualize blood vessels

E) Green staining to visualize elastin fibers

What is the primary function of the endocrine system?

A) To secrete digestive enzymes

B) To synthesize and secrete hormones directly into blood and lymph capillaries

C) To excrete waste products

D) To filter blood

E) To produce red blood cells

What is the function of somatostatin?

A) Stimulates the release of thyrotropin (TSH)

B) Inhibits the release of somatotropin (GH) and TSH

C) Stimulates the release of prolactin (PRL)

D) Stimulates the release of growth hormone (GH)

E) Inhibits the release of corticotropin (ACTH)

What is a primary characteristic of dense connective tissue?

A) High cellular content

B) Predominance of fiber elements over cells and ground substance

C) Abundance of ground substance

D) Sparse collagen fibers

E) High metabolic activity

What is a defining feature of dense regular connective tissue?

A) Randomly interwoven collagen fibers

B) Fibroblasts aligned parallel to resist stress in the same direction

C) Abundant ground substance

D) Sparse fibroblasts

E) Scattered reticular fibers

What surrounds each muscle fiber and is called the endomysium?

A) Sarcolemma

B) Basal lamina

C) Myofilaments

D) Sarcoplasm

E) Intercalated discs

Which type of connective tissue is made up of a delicate network of reticular fibers?

A) Dense regular connective tissue

B) Dense irregular connective tissue

C) Reticular connective tissue

D) Adipose tissue

E) Embryonic connective tissue

What is the role of canaliculi in bone tissue?

A) Store lipids

B) Contain blood vessels

C) Secrete collagen fibers

D) Produce heat

E) Store minerals

Where is dense irregular connective tissue commonly found?

A) In ligaments

B) In tendons

C) In the dermis of the skin and organ capsules

D) In the umbilical cord

E) In the dental pulp

Which type of muscle tissue has slow, involuntary contractions and lacks striations?

A) Skeletal muscle

B) Cardiac muscle

C) Smooth muscle

D) Striated muscle

E) Voluntary muscle

Which muscle type lacks sarcomeres and striations?

A) Skeletal muscle

B) Cardiac muscle

C) Smooth muscle

D) All muscle types

E) None of the above

What are the main components of the pars distalis in the adenohypophysis?

A) Chromophobes and neurons

B) Chromophils and chromophobes

C) Chromophils and neurons

D) Chromophobes and neurons

E) Chromophils and fenestrated capillaries

What is the primary function of acidophils in the pars distalis?

A) Secretion of ACTH

B) Secretion of FSH and LH

C) Secretion of growth hormone and prolactin

D) Secretion of TSH

E) Secretion of β-endorphin

From which part of the brain does the neuroectodermal down growth that forms the neurohypophysis originate?

A) Cerebellum

B) Medulla oblongata

C) Diencephalon

D) Pons

E) Cerebrum

Which artery supplies blood mainly to the neurohypophysis?

A) Superior hypophyseal arteries

B) Inferior hypophyseal arteries

C) Carotid artery

D) Vertebral artery

E) Basilar artery

What is the function of ependymal cells in the CNS?

A) Myelinate axons

B) Provide structural support

C) Line ventricles of the brain and central canal of the spinal cord

D) Mediate immune defense activity

E) Insulate PNS axons

What occurs during endochondral ossification?

A) Direct differentiation of osteoblasts from mesenchyme

B) Pre-existing cartilage matrix is eroded and invaded by osteoblasts

C) Formation of lipid droplets in adipocytes

D) Secretion of collagen fibers by chondroblasts

E) Conversion of white adipose tissue to brown adipose tissue

What is the role of the sarcoplasmic reticulum (SR) in muscle contraction?

A) Sequestration and release of Ca2+

B) Formation of crossbridges

C) Attachment of myosin heads to actin

D) Depolarization of the sarcolemma

E) Generation of ATP

Which muscle type has the best capacity for regeneration?

A) Skeletal muscle

B) Cardiac muscle

C) Smooth muscle

D) All muscle types have equal capacity

E) None of the above

What structure is derived from the hypophyseal (Rathke) pouch?

A) Neurohypophysis

B) Adenohypophysis

C) Thyroid gland

D) Pineal gland

E) Adrenal medulla

Which cells in the pars distalis secrete FSH and LH?

A) Corticotrophs

B) Somatotrophs

C) Lactotrophs

D) Gonadotrophs

E) Thyrotrophs

Which part of the adenohypophysis is best developed and active during fetal life?

A) Pars distalis

B) Pars nervosa

C) Pars intermedia

D) Pars tuberalis

E) Pars anterior

Which hormones are synthesized by the hypothalamic supraoptic and paraventricular nuclei?

A) Growth hormone and prolactin

B) Thyroid-stimulating hormone and adrenocorticotropic hormone

C) Follicle-stimulating hormone and luteinizing hormone

D) Antidiuretic hormone and oxytocin

E) Melatonin and serotonin

What are the three connective tissue layers that enclose the CNS called?

A) Epineurium, Perineurium, Endoneurium

B) Dura mater, Arachnoid layer, Pia mater

C) Myelin sheath, Nodes of Ranvier, Schwann cells

D) Astrocytes, Oligodendrocytes, Microglia

E) Choroid plexus, Ependyma, Blood-brain barrier

Which type of connective tissue is characterized by the presence of numerous fibroblasts and collagen?

A) Dense regular connective tissue

B) Dense irregular connective tissue

C) Loose/areolar connective tissue

D) Reticular connective tissue

E) Adipose tissue

Which neurotransmitter is involved in the synapses of motor axons with skeletal muscle?

A) Dopamine

B) Serotonin

C) Acetylcholine

D) Norepinephrine

E) Glutamate

What is the primary difference between cardiac and skeletal muscle fibers?

A) Presence of sarcomeres

B) Presence of striations

C) Number of nuclei per cell

D) Type of filaments

E) Ability to regenerate

What is the major source of ATP for Fast, Glycolytic Fibers (Type IIb)?

A) Oxidative phosphorylation

B) Anaerobic respiration

C) Glycolysis

D) Creatine phosphate

E) Aerobic respiration

What is the primary function of brown adipose tissue?

A) Long-term energy storage

B) Heat production and warming the blood

C) Structural support

D) Lubrication of joints

E) Storage of minerals

Which glial cell type is found in the PNS and is responsible for myelinating large-diameter axons?

A) Oligodendrocyte

B) Schwann Cell

C) Microglial Cell

D) Astrocyte

E) Ependymal Cell

What is the primary function of neurons?

A) Provide structural support

B) Conduct immune defense

C) Produce and move action potentials

D) Insulate axons

E) Line cerebral ventricles

What is the role of pituicytes in the posterior pituitary?

A) Conduct action potentials

B) Produce ADH and oxytocin

C) Resemble astrocytes and are the most abundant cell type

D) Stimulate the release of growth hormone (GH)

E) Inhibit the release of corticotropin (ACTH)

Which muscle type is primarily responsible for involuntary movements?

A) Skeletal muscle

B) Cardiac muscle

C) Smooth muscle

D) Both B and C

E) All of the above

Which type of neuron is characterized by a cell body containing the nucleus, a long cytoplasmic extension called the axon, and one or more shorter processes called dendrites?

A) Glial cell

B) Astrocyte

C) Neuron

D) Schwann cell

E) Ependymal cell

What is the primary reason for the difficulty in regeneration within the CNS after major injury?

A) Lack of Schwann cells

B) Complexity and distances of neuronal and glial interconnections

C) Absence of blood-brain barrier

D) High salinity levels

E) Lack of connective tissue

What triggers the release of Ca2+ from the sarcoplasmic reticulum?

A) Formation of crossbridges

B) Depolarization of the sarcolemma

C) ATP hydrolysis

D) Attachment of myosin heads to actin

E) Presence of acetylcholine

What allows for the regeneration of skeletal muscle tissue?

A) Presence of satellite cells

B) Presence of intercalated discs

C) High mitotic activity

D) Dense bodies in the sarcoplasm

E) Intrinsic contraction

Which muscle fiber type is known for having numerous mitochondria and high myoglobin content?

A) Slow, Oxidative Fibers (Type I)

B) Fast, Oxidative-Glycolytic Fibers (Type IIa)

C) Fast, Glycolytic Fibers (Type IIb)

D) Both A and B

E) All of the above

What controls the contraction in smooth muscle?

A) Troponin C binding to Ca2+

B) Myosin phosphorylation by MLCK

C) Actin binding to ATP

D) Troponin I binding to Ca2+

E) Tropomyosin binding to ATP

What is the main protein synthesized in corticotrophs?

A) Growth hormone

B) Prolactin

C) Pro-opiomelanocortin (POMC)

D) Thyroid-stimulating hormone

E) Luteinizing hormone

What is the main characteristic of white adipose tissue?

A) Multi-globular lipid inclusions

B) Specialized for short-term energy storage

C) Contains a single large droplet of lipid

D) Found mainly in newborns

E) Contains abundant mitochondria

During early embryonic development, what structure forms the precursor of the CNS?

A) Neural crest

B) Neural tube

C) Dorsal ectoderm

D) Neural plate

E) Ventral ectoderm

What is the primary function of the choroid plexus?

A) Electrical insulation

B) Structural support

C) Production and movement of CSF

D) Removal of water from capillaries and transfer into ventricles as CSF

E) Defense and immune-related activities

Which hormones are stored and released by the neurohypophysis?

A) Growth hormone and prolactin

B) Thyroid-stimulating hormone and adrenocorticotropic hormone

C) Follicle-stimulating hormone and luteinizing hormone

D) Antidiuretic hormone and oxytocin

E) Melatonin and serotonin

What is the appearance of white adipocytes in standard light microscopy?

A) Multi-globular

B) Signet ring appearance

C) Polyhedral

D) Spherical

E) Flattened

Which part of the adenohypophysis wraps around the infundibulum?

A) Pars distalis

B) Pars tuberalis

C) Pars intermedia

D) Pars nervosa

E) Pars anterior

What is the function of Schwann cells in peripheral nerves?

A) Myelin production and electrical insulation

B) Structural and metabolic support of neurons

C) Aid production and movement of CSF

D) Defense and immune-related activities

E) Formation of the blood-brain barrier

Where is brown adipose tissue primarily located in newborns?

A) Around the kidneys

B) In the back, neck, and shoulders

C) Around the aorta

D) In the lower limbs

E) In the abdominal cavity

What is the role of microglial cells in the CNS?

A) Myelinate axons

B) Provide structural support

C) Line cerebral ventricles

D) Mediate immune defense activity

E) Insulate PNS cell bodies

What are osteocytes?

A) Cells that secrete fibers and ground substance

B) Cells trapped in lacunae

C) Cells involved in heat production

D) Cells that store energy

E) Cells that form blood vessels

What is the main function of astrocytes in the CNS?

A) Myelin production

B) Structural and metabolic support of neurons

C) Aid production and movement of CSF

D) Defense and immune-related activities

E) Electrical insulation

Which of the following retains neural stem and progenitor cells allowing some replacement of neurons throughout life?

A) Peripheral nerves

B) Schwann cells

C) Ependyma

D) Choroid plexus

E) Blood-brain barrier

What is the main function of microglia in the CNS?

A) Myelin production

B) Structural support

C) Aid production and movement of CSF

D) Defense and immune-related activities

E) Electrical insulation

Loose/areolar connective tissue is very common in our body and supports ___.

epithelial tissue

___ electrically insulate PNS cell bodies.

Satellite Cells

Mesenchyme is a tissue developed mainly from the middle layer of the embryo, known as the ___ germ layer.

mesodermal

Dense regular connective tissue can be found in ___, ___, and ___.

ligaments, tendons, aponeuroses

To differentiate fibrocartilage, a special stain is used to visualize numerous ___ fibers, which appear with a specialized blue stain.

collagen

Striations are ___ in skeletal and cardiac muscles but ___ in smooth muscle.

present, absent

The major constituent of connective tissue is the ___, which consists of different combinations of protein fibers and ground substance.

extracellular matrix

Fast, glycolytic fibers (Type IIb) have ___ mitochondria and rely on ___ respiration for ATP.

sparse, anaerobic

The location of nuclei in skeletal muscle is ___, adjacent to the sarcolemma.

peripheral

Connective tissue has more ___ material compared to epithelial tissue.

intercellular

Every muscle fiber is surrounded by a basal lamina called the ___.

endomysium

Cardiac muscle cells are bound to one another at structures called ___ ___.

intercalated discs

Skeletal muscle fibers are ___ in shape and can be many centimeters long.

cylindrical

Secretion in the zona fasciculata is controlled by ___ with negative feedback proportional to circulating glucocorticoids.

ACTH

Skeletal muscle contraction is controlled by ___ nervous system innervation.

motor

Dense connective tissue is adapted to offer stress ___ and ___.

resistance, protection

Dense irregular connective tissue can be found in the ___ of the skin, organ capsules, and submucosal layer of the gastrointestinal tract.

dermis

Within the sarcoplasm are cytoplasmic contractile elements known as ___.

myofilaments

Cortisol suppresses many ___ functions and can induce fat mobilization and muscle ___.

immune, proteolysis

The zona reticularis comprises about ___% of the adrenal cortex.

10

A muscle's ability to return to its original position after elongation is known as ___.

elasticity

Dense connective tissue can be categorized into ___ and ___ types.

regular, irregular

The sensory division (afferent) of the nervous system consists of the ___ sensory input perceived consciously and the ___ sensory input not perceived consciously.

somatic, visceral

The ___ is a single long process ending at a synapse, specialized to generate and conduct nerve impulses to other cells.

axon

Endocrine glands are ___ because they do not have excretory ducts.

ductless

The hypothalamic-hypophyseal portal system consists of two capillary networks connected by the ___ ___ ___.

hypophyseal portal vein

In endochondral ossification, a pre-existing matrix is eroded and invaded by ___, which then begin osteoid production.

osteoblasts

Chondroblasts secrete ___ and ___.

fibers, ground substance

Aldosterone secretion is primarily stimulated by ___ and also by an increase in plasma ___ concentration.

angiotensin II, K+

Cells of the zona reticularis primarily secrete ___, including ___ (DHEA) that is converted to testosterone.

weak androgens, dehydroepiandrosterone

The basic function of muscle is to generate force (___) to make locomotion possible.

propulsion

The peripheral nervous system (PNS) is composed of the ___, ___, and ___ nerves.

cranial, spinal, peripheral

The three main parts of a neuron are the ___ (cell body), ___, and ___.

perikaryon, dendrites, axon

The neural component of the pituitary gland is also known as the ___ or ___ lobe.

neurohypophysis, posterior

White adipose tissue is specialized for ___ energy storage.

long term

White adipocytes sometimes have a ___ appearance due to the lipid droplet displacing and flattening the material against the cell membrane.

signet ring

Cells in the zona fasciculata secrete ___, especially ___, which affect carbohydrate metabolism.

glucocorticoids, cortisol

Unlike bone, cartilage is ___, meaning it lacks blood vessels.

avascular

Neurons typically have numerous long processes, while glial cells have ___ processes.

short

Reticular connective tissue can be found in bone marrow, liver, ___, and lymphoid organs.

adrenal gland

The epithelial component of the pituitary gland is also known as the ___, ___ lobe, or ___ ___.

adenohypophysis, anterior, pars distalis

The adenohypophysis is derived from the ___ ___ and has three parts: the ___ ___ or anterior lobe, the ___ ___, and the thin ___ ___.

oral ectoderm, pars distalis, pars tuberalis, pars intermedia

White adipocytes are spherical when isolated but are ___ when closely packed.

polyhedral

Canaliculi in bone contain ___.

blood vessels

Each muscle fiber is filled with ___, composed of thick ___ filaments and thin ___ filaments, organized into units called ___.

myofibrils, myosin, actin, sarcomeres

The three parts of the adenohypophysis are derived embryonically from the ___ pouch.

hypophyseal

Each adrenal gland has two concentric regions: a yellowish ___ and a reddish-brown central ___.

adrenal cortex, adrenal medulla

___ are the most numerous cell of the CNS and produce hundreds of processes to cover neuronal perikarya, synapses, and capillaries.

Astrocytes

Somatostatin is a 14-amino acid peptide that inhibits the release of both somatotropin (GH) and ___.

TSH

Dopamine inhibits the release of ___.

prolactin (PRL)

The steroids made by cells in the zona glomerulosa are called ___ because they affect the uptake of Na+, K+, and water by cells of renal tubules.

mineralocorticoids

In smooth muscle, actin-myosin binding occurs with myosin phosphorylation by ___ triggered when calmodulin binds Ca2+.

MLCK

Smooth muscle can undergo both hypertrophy and ___ (increase in cell/fiber number).

hyperplasia

Dense irregular connective tissue has collagen fiber bundles that appear ___ interwoven without definite orientation.

randomly

In hyaline cartilage, you can see the ___, ___, and ___ in the cells.

lacunae, fibroblasts, chondroblasts

Cardiac muscle fibers are cylindrical and have a diameter of 10-20 μm and a length of ___-___ μm.

50-100

The epithelial component of the pituitary gland is derived from the ___ ___, which arises as an outpocketing of ectoderm from the roof of the primitive mouth.

hypophyseal (Rathke) pouch

The principal function of brown adipose tissue is ___ and warming the blood.

heat production

White adipocytes contain a single large droplet of triglycerides and are also called ___.

unilocular

Hormones, like neurotransmitters, are frequently ___ molecules such as proteins, glycoproteins, peptides, or modified amino acids with receptors on the surface of target cells.

hydrophilic

There are ___ major kinds of glial cells, four in the CNS and two in the PNS.

six

The CNS is completely enclosed by three connective tissue layers called ___: dura mater, arachnoid layer, and pia mater.

meninges

Each adrenal gland is covered by a dense connective tissue capsule that sends thin ___ into the gland’s parenchyma.

trabeculae

Chromophils are secretory cells in which hormone is stored in cytoplasmic granules. They are also called ___ and ___ based on their affinities for basic and acidic dyes, respectively.

basophils, acidophils

Chromophobes stain weakly, with few or no secretory granules, and represent a heterogeneous group including stem and undifferentiated ___ cells as well as any degranulated cells present.

progenitor

Peripheral nerves consist of axons from motor neurons, sensory neurons, and autonomic neurons, all enclosed within a series of ___.

Schwann cells

Neurosecretory bodies or Herring bodies contain membrane-enclosed granules with either oxytocin or ADH bound to 10-kDa carrier proteins called ___.

neurophysin I and II

Oxytocin stimulates the contraction of mammary gland myoepithelial cells and uterine smooth muscle, and it produces psychological effects such as the promotion of ___ behavior.

pair-bonding

___ involves the formation and remodeling of synaptic connections and is prevalent throughout life.

Neural plasticity

Dense connective tissue differs from areolar tissues because it contains fewer ___ and a predominance of ___ elements over the cells and ground substance.

cells, fiber

The plasma membrane of a muscle fiber is often called the ___.

sarcolemma

Embryonic connective tissue is characterized by abundant ground substance with a ___ appearance.

jelly-like

Adipose tissue serves as storage depots for ___ fats and regulates the metabolic activity of the body.

neutral

The neurohypophysis mainly contains ___ ___ and their axons, and functions in storing and releasing the secretory products of the hypothalamus.

neurosecretory axons

The cells in most endocrine tissues and organs are arranged into ___ and ___ and are surrounded by an extensive capillary network.

cords, clumps

In paracrine secretion, localized dispersal occurs in interstitial fluid or through short loops of blood vessels, as when ___ made by pyloric G cells reaches target cells in the fundic glands.

gastrin

___ provides structural support and organization to the CNS.

Astrocyte

Inhibiting hormones block hormone secretion in specific cells of the ___.

adenohypophysis

The main components of the pars distalis are cords of well-stained endocrine cells interspersed with ___ capillaries and supporting reticular connective tissue.

fenestrated

The myosin heads pivot with ___ hydrolysis, which pulls the thin filaments along the thick filaments.

ATP

Cortical capillaries irrigate endocrine cells of the cortex and then drain into the microvasculature of the medulla, giving the adrenal medulla a dual blood supply from ___ blood from the medullary arterioles and ___ blood from capillaries of the cortex.

arterial, venous

Pro-opiomelanocortin (POMC) is the main protein synthesized in ___ and is cleaved posttranslationally into adrenocortical trophic hormone (ACTH) and β-lipotropin (β-LPH).

corticotrophs

The neurohypophysis consists of the pars nervosa and the infundibular stalk and does not contain the cells that synthesize its ___ hormones.

two

Secretory neurons in the neurohypophysis have larger-diameter axons and produce antidiuretic hormone (ADH) and ___.

oxytocin

Regeneration is rapid in smooth muscle because the cells/fibers are small and relatively less ___, which allows renewed mitotic activity after injury.

differentiated

___ can be either sensory or autonomic and contain neuronal cell bodies and their satellite cells, surrounded by connective tissue continuous with that of nerves.

Ganglia

In cardiac muscle, intercalated discs join cells with many ___ and ___ junctions.

adherent, gap

All connective tissues originate from the embryonic ___.

mesenchyme

The three types of cartilage in the body are ___, ___, and ___.

hyaline, elastic, fibrocartilage

Dense regular connective tissue has collagen fiber bundles that appear in a definite ___ pattern.

parallel

Muscles are classified based on morphology (presence or absence of ___) and function (voluntary or involuntary).

striations

Reticular connective tissue is made up of a delicate network of reticular fibers, which are type ___ collagen with attached specialized fibroblasts called reticular cells.

III

The cell body of a neuron, also called the ___ or ___, contains the nucleus and most of the cell's organelles.

perikaryon, soma

The neurohypophysis retains many histologic features of ___ tissue and consists of a large part, the ___ ___, and the smaller ___ ___ attached to the hypothalamus.

brain, pars nervosa, infundibulum stalk

Mixed (endocrine-exocrine) organs include the ___, kidneys, reproductive organs of both sexes, placenta, and gastrointestinal tract.

pancreas

In standard microscopy, unilocular adipocytes often appear ___ due to the removal of lipid by solvents.

empty

___ myelinates and insulates CNS axons.

Oligodendrocytes

Releasing hormones stimulate secretion by specific ___ pituitary cells.

anterior

The delicate inner layer of the meninges that directly contacts neural tissue is the ___.

pia mater

The adrenal cortex arises from ___, while the adrenal medulla arises from the ___.

mesoderm, neural crest

___ are glial cells that line the ventricles and central canal of the CNS and aid in the production and movement of CSF.

Ependymal cells

___ are located within PNS ganglia and regulate the microenvironment of neuronal cell bodies.

Satellite Cells

The adrenal cortex has three concentric zones: the outermost zone is the ___, which comprises about 15% of the cortex and consists of closely packed, rounded or arched cords of columnar or pyramidal cells with many capillaries.

zona glomerulosa

In large peripheral nerves, groups of axons are subdivided as ___, each surrounded by perineurium.

fascicles

Cardiac muscle contraction is ___ and begins at nodes of conducting fibers.

intrinsic

___ are mature chondroblasts isolated in lacunae.

Chondrocytes

The central nervous system (CNS) consists of the ___ and ___ ___.

brain, spinal cord

Glial cells support neuronal survival and activities and are ___ times more abundant than neurons in the mammalian brain.

ten

The hypothalamic-hypophyseal tract consists of axons extending from the hypothalamic ___ and ___ nuclei, through the infundibulum, and into the pars nervosa of the posterior pituitary.

supraoptic, paraventricular

Bone is the ___ connective tissue.

hardest

In the CNS, glial cells surround both the neuronal cell bodies and the processes of ___ and ___.

axons, dendrites

___ surround and insulate PNS axons and myelinate those with large diameters.

Schwann Cells (Neurolemmocytes)

Ghrelin, produced mainly in the ___ mucosa, acts as a releasing hormone for somatotropin secretion.

stomach

___ are glial cells in the CNS that provide structural and metabolic support of neurons, especially at synapses.

Astrocytes

___ mediate immune defense activity within the CNS and originate from blood monocytes.

Microglia

Contraction of cardiac muscle is ___ at nodes of impulse-generating pacemaker muscle fibers; autonomic nerves regulate the rate of contraction.

intrinsic

Thin and thick filaments in smooth muscle fibers do not form ___, and no ___ are present.

sarcomeres, striations

Connective tissues provide ___, ___, and ___ various parts of the body.

support, anchor, connect

Slow, oxidative fibers (Type I) have ___ myoglobin content and are known as ___ fibers.

high, red

The interstitial fluid of connective tissue gives ___ support to the cells as the medium for diffusion of nutrients and waste products.

metabolic

Unlike epithelial tissue, connective tissue has (+) ___ ground substance.

amorphous

Smooth muscle consists of collections of ___ cells that lack striations.

fusiform

Endocrine cells are typically ___ in origin and aggregated as cords or clusters.

epithelial

The pituitary gland is often called the ___ gland because it controls so many bodily functions.

master

Sarcomeres are separated by ___ that bisect the light-staining ___ bands that contain mainly the thin filaments attached to ___ in the Z disc.

Z discs, I, α-actinin

Neurons use the common cell property of ___ to produce and move an action potential.

excitability

___ wrap processes around portions of axons in the CNS, forming myelin sheaths.

Oligodendrocytes

Muscle spindles and tendon organs are both ___ proprioceptors in which ___ axons wrap around ___ fibers in small specialized fascicles or around myotendinous collagen bundles.

sensory, sensory, intrafusal

___ are glial cells in peripheral ganglia that provide structural and metabolic support for neuronal cell bodies.

Satellite cells

Corticotrophs of the pars intermedia express POMC but cleave it differently from cells in the pars distalis, producing smaller peptide hormones, including two forms of ___-stimulating hormone (MSH), γ-LPH, and β-endorphin.

melanocyte

The thick, outermost layer of dense irregular connective tissue surrounding the perineurium in peripheral nerves is called the ___.

epineurium

The zona fasciculata occupies ___% - ___% of the adrenal cortex.

65, 80

Secretion by cells in the zona reticularis is stimulated by ___ with regulatory feedback.

ACTH

The unit of muscle tissue is a cell, often referred to as a ___ ___.

muscle fiber

Skeletal muscle contains bundles of very long, multinucleated cells with cross ___.

striations

The motor division (efferent) of the nervous system consists of the ___ motor output controlled consciously and the ___ motor output not controlled consciously.

somatic, autonomic

Smooth muscle fibers are fusiform in shape with a diameter of 0.2-10 μm and a length of ___-___ μm.

50-200

Brown adipocytes contain many small lipid inclusions and are therefore called ___.

multi-globular

A fully developed white adipocyte can be between ___ to ___ micrometers in diameter.

50, 150

Osteocytes are trapped in ___.

lacunae

Between the two I bands of a sarcomere is the dark-staining ___ band with the thick ___ filaments; alternating light and dark bands appear as microscopic ___.

A, myosin, striations

The ___ consists of elaborate folds of vascularized pia mater covered by ependyma that project from the walls of the cerebral ventricles.

choroid plexus

___ are glial cells in the CNS responsible for myelin production and electrical insulation.

Oligodendrocytes

___ are glial cells derived from bone marrow (monocytes) and are involved in defense and immune-related activities in the CNS.

Microglia

Regions rich in neuronal perikarya and astrocytes in the brain and spinal cord are called ___ matter.

gray

Large, unique ___ neurons characterize the cortex of the cerebellum.

Purkinje

Specialized connective tissue includes ___, ___, ___, ___, and ___.

reticular, adipose, bone, blood, cartilage

The pituitary gland is a dual gland consisting of an ___ component and a ___ component.

epithelial, neural

Adipose tissue can be found in subcutaneous fat, omentum, mesentery, inguinal, axillary, and ___ regions.

cervical

Compared to exocrine glands, the structure of endocrine glands is much simpler, usually consisting of a ___, followed by connective tissue, and the parenchyma consisting of networks of reticular fibers.

capsule

In intramembranous ossification, osteoblasts differentiate directly from ___ and begin creating osteoid.

mesenchyme

The pituitary gland or hypophysis weighs about ___ g in adults and has dimensions of about 10 × 13 × 6 mm.

0.5

Within sarcomeres, thick and thin filaments interdigitate; globular ___ heads project from the thick filaments toward the ___ filaments, which are associated with ___ and ___.

myosin, F-actin, tropomyosin, troponin

Negative feedback is a mechanism controlling the activity of anterior pituitary cells, made by hormones from the ___ organs.

target

Ca2+ binding to ___ causes ___ to change shape and allow the myosin heads to bind the actin subunits, forming ___ between thick and thin filaments.

troponin, tropomyosin, crossbridges

Synapses of motor axons with skeletal muscle are called ___, ___, or ___; the neurotransmitter is ___.

MEPs, NMJs, myoneural junctions, acetylcholine

Gonadotrophs secrete two different glycoproteins: ___ and ___ (called interstitial cell-stimulating hormone [ICSH] in men).

Follicle-stimulating hormone (FSH), Luteinizing hormone (LH)

Cardiac muscle fibers are also ___, but they consist of individual cylindrical cells, each containing one (or two) central nuclei and linked by adherent and gap junctions at prominent ___.

striated, intercalated discs

The pars intermedia contains basophils (corticotrophs), chromophobes, and small, colloid-filled cysts derived from the lumen of the embryonic ___ pouch.

hypophyseal

The hypothalamic hormones control the activities of the cells of the anterior pituitary and are produced by small neurons near the ___ ventricle.

third

Certain regions of the CNS retain rare ___ that allow some replacement of neurons throughout life.

neural stem and progenitor cells

The human nervous system is formed by a network of many billion nerve cells (___), all assisted by many more supporting cells called ___ cells.

neurons, glial

Elastic cartilage can be distinguished from hyaline cartilage using a special stain that highlights ___ fibers.

elastin

Embryonic connective tissue can be found in ___ and dental pulp.

Wharton’s Jelly (umbilical cord)

The ___ are numerous elongated processes extending from the perikaryon and specialized to receive stimuli from other neurons at unique sites called ___.

dendrites, synapses

In autocrine secretion, cells may produce molecules that act on themselves or on cells of the same type, such as ___ produced by several cell types.

insulin-like growth factor (IGF)

___ protect the CNS by engulfing infectious agents and harmful substances.

Microglial Cells

Nervous tissue develops in the early embryo when the dorsal ectoderm neural plate folds to form the ___, the precursor of the CNS.

neural tube

Oxytocin, released in the posterior pituitary during breast-feeding, increases the secretion of ___.

prolactin

The adrenal gland lacks a ___; superior, middle, and inferior suprarenal arteries penetrate the capsule independently and branch immediately to form a ___.

hilum, subcapsular arterial plexus

A motor axon may form many terminal branches, each ending on an MEP of a muscle fiber; all fibers innervated by branches of that axon comprise a ___.

motor unit

Ultrastructurally, the cytoplasm of adrenal cortex cells shows an exceptionally profuse ___ of interconnected tubules, which contain the enzymes for cholesterol synthesis and conversion of the steroid prohormone ___ into specific active steroid hormones.

smooth ER (SER), pregnenolone

Smooth muscle fibers are individual small, fusiform (tapering) cells, linked by numerous ___.

gap junctions

Groups of axons (with Schwann cells and endoneurium) are surrounded by ___, consisting of layered, squamous fibroblastic cells joined by tight junctions to make a blood-nerve barrier.

perineurium

The predominant cells in adipose tissue are ___, also known as fat cells.

adipocytes

The brown color of brown adipose tissue is due to the abundant ___ and the larger number of ___.

mitochondria, blood capillaries

Hormones are signaling molecules that are released into the neighboring vascularized compartment for uptake by ___ and distribution throughout the body.

capillaries

The tough external layer of the meninges is called the ___.

dura mater

The stroma of the adrenal glands consists mainly of ___ fibers supporting the secretory cells and microvasculature.

reticular

Thyrotropin-releasing hormone (TRH) is a ___-amino acid peptide that stimulates the release of thyrotropin (TSH).

3

Growth hormone-releasing hormone (GHRH) stimulates the release of ___.

GH

Mitochondria in adrenal cortex cells are often spherical, with tubular rather than shelflike cristae, and contain the enzymes for converting cholesterol to ___ and for some steps in steroid synthesis.

pregnenolone

Vasopressin/antidiuretic hormone (ADH) increases water permeability of renal collecting ducts and is released in response to increased blood ___, sensed by osmoreceptor cells in the hypothalamus.

tonicity

The more simply organized peripheral nerves have better capacity for ___, a process involving reactivation of the perikaryon, Schwann cells, and macrophages.

axonal regeneration

Brown adipose tissue constitutes ___ to ___ percent of the newborn body weight.

two, five

The endocrine system consists of cells, tissues, and organs that synthesize and secrete ___ directly into blood and lymph capillaries.

hormones

The superior hypophyseal arteries supply the ___ ___ and the ___ ___.

median eminence, infundibular stalk

In juxtacrine secretion, a signaling molecule remains on the secreting cell’s surface or adjacent extracellular matrix and affects target cells when the cells make ___.

contact

The extracellular matrix of cartilage contains ___ and ___.

collagen, elastic fibers

___ line ventricles of the brain and central canal of the spinal cord.

Ependymal Cells

The middle layer of the meninges that contains much CSF is called the ___.

arachnoid layer

Nerve communication is transmitted via a ___, where neurotransmitter is released at the presynaptic membrane.

synapse

Gonadotropin-releasing hormone (GnRH) stimulates the release of both ___ and luteinizing hormone (LH).

follicle-stimulating hormone (FSH)

In the PNS, ___ produce myelin sheaths around large-diameter axons.

Schwann Cells (Neurolemmocytes)

Steroid hormones are not stored in granules like proteins nor undergo exocytosis; they diffuse freely from cells through the ___.

plasma membrane

Repair and regeneration can occur in skeletal muscle because of a population of reserve ___ cells that can proliferate, fuse, and form new muscle fibers.

muscle satellite

In adults, brown adipose tissue is found mainly around the ___, ___, ___, and ___.

kidneys, adrenal glands, aorta, mediastine

Embryologically, anatomically, and functionally, the ___ ___ is connected to the ___ at the base of the brain.

pituitary gland, hypothalamus

___ and ___ are peptide hormones synthesized by large neurons in the supraoptic and paraventricular nuclei, respectively.

ADH (antidiuretic hormone), oxytocin

Endocrine glands have a rich ___ for the distribution of hormones.

blood supply

Hydrophobic steroid and thyroid hormones must circulate on ___ but can diffuse through the cell membranes and activate cytoplasmic receptors in target cells.

transport proteins

The pituitary gland lies below the brain in a small cavity on the sphenoid bone called the ___.

sella turcica

The adrenal (or suprarenal) glands are paired organs lying near the superior poles of the ___, embedded in the pararenal adipose tissue and fascia.

kidneys

The ___ accounts for 75% of the adenohypophysis and has a thin fibrous capsule.

pars distalis

Corticotropin-releasing hormone (CRH) stimulates the synthesis of pro-opiomelanocortin (POMC) and the release of both β-lipotropic hormone (β-LPH) and ___.

corticotropin (ACTH)

Regions containing tracts of myelinated axons in the CNS are called ___ matter.

white

Cardiac muscle lacks ___ cells and has little capacity for regeneration.

satellite

Groups of muscle fibers called ___ are surrounded by ___; all fascicles are enclosed within a dense connective tissue ___

fascicles, perimysium, epimysium

Adrenal glands are flattened structures with a half-moon shape, about ___ cm long, ___ cm wide, and ___ mm thick in adults.

4-6, 1-2, 4-6

At each sarcomere, two terminal ___ of SR contact a deep invagination of the sarcolemma called a ___ or ___, forming a ___ that triggers Ca2+ release when the sarcolemma is depolarized.

cisterns, transverse, T-tubule, triad

Acidophils secrete either growth hormone (somatotropin) or prolactin (PRL) and are called ___ and ___, respectively.

somatotrophs, lactotrophs

___ are epithelial-like cells that line the fluid-filled cerebral ventricles and central canal of the spinal cord.

Ependymal Cells

Cells of the adrenal cortex have characteristic features of ___ cells: acidophilic cytoplasm rich in lipid droplets, with central nuclei.

steroid-secreting

The pars tuberalis is a smaller funnel-shaped region surrounding the ___ of the neurohypophysis.

infundibulum

The thin connective tissue layer immediately surrounding Schwann cells in peripheral nerves is called ___.

endoneurium

In the sarcoplasm between parallel myofibrils are ___ and cisternae of smooth ER, called the ___, specialized for Ca2+ sequestration and release.

mitochondria, sarcoplasmic reticulum

In most CNS regions, neurons are protected by the ___, consisting of the perivascular feet of astrocytic processes and nonfenestrated capillary endothelial cells' tight junctions.

blood-brain barrier

The basophilic cells are the corticotrophs, gonadotrophs, and thyrotrophs, with target cells in the ___, ___, and ___ gland, respectively.

adrenal cortex, gonads, thyroid

___ are glial cells in peripheral nerves responsible for myelin production and electrical insulation.

Schwann cells

Pituicytes are highly branched glial cells that resemble ___.

astrocytes

The principal product of the zona glomerulosa is ___, the major regulator of salt balance, which acts to stimulate Na+ uptake.

aldosterone