p.9
Epidermis Structure and Layers
What type of cells primarily make up the stratum spinosum?
Polyhedral cells active in keratin synthesis.
p.19
Dermis Composition and Function
How variable is the thickness of the dermis?
It varies, being thickest on the back.
p.33
Hair Structure and Growth
What are the two layers of the epithelial root sheath?
Internal root sheath and external root sheath.
p.17
Epidermis Structure and Layers
What attaches the dermis to the basement membrane?
Collagen anchoring fibrils.
p.23
Thermoregulation and Vascular Supply of the Skin
What are vascular plexuses in the skin?
Networks of blood vessels that supply the skin.
p.8
Epidermis Structure and Layers
What type of cells primarily make up the stratum basale?
Basophilic cuboidal cells.
p.9
Epidermis Structure and Layers
What is the stratum spinosum?
A thick epidermal layer that is thicker in thick skin.
p.11
Epidermis Structure and Layers
What is the stratum lucidum?
A translucent layer found only in thick skin.
p.21
Dermis Composition and Function
What is the benefit of making surgical incisions parallel to tension lines?
They are associated with faster healing and less scarring.
p.37
Hair Structure and Growth
What is the nature of hair growth?
Hair growth is cyclical but asynchronous, occurring at different rates in different regions of the body.
p.11
Epidermis Structure and Layers
What type of cells make up the stratum lucidum?
Eosinophilic squamous cells with no nuclei and organelles.
p.24
Sensory Receptors in the Skin
What type of nerves enter the skin and where do they end?
Afferent sensory nerves enter the skin and end at epithelial and dermal receptors.
p.50
Cultural Significance of Numbers
What is the significance of the number 50 in various cultures?
In many cultures, 50 symbolizes completion or a milestone, such as a 50th anniversary.
p.21
Dermis Composition and Function
What causes collagen fibers in the reticular region of the dermis to orient in specific directions?
Natural tension from bony projections, muscle orientation, and joint movements.
p.35
Hair Structure and Growth
What does a cross section through the hair follicle show?
The structure of the hair follicle.
p.26
Sensory Receptors in the Skin
Where are free nerve endings located and what do they respond to?
In the papillary dermis and lower epidermal layers; they respond to temperature, pain, and itching.
How does the skin contribute to thermoregulation?
Through sweating and superficial vasculature.
What is a common use of the number 50 in sports?
In American football, a 50-yard line marks the midpoint of the field.
p.30
Dermis Composition and Function
What type of tissue primarily makes up the subcutaneous layer?
Loose fatty connective tissue.
p.27
Sensory Receptors in the Skin
What is the structure of Meissner corpuscles?
They consist of a fibrous capsule, several flattened Schwann cells arranged as lamellae, and an unmyelinated nerve fiber.
p.26
Sensory Receptors in the Skin
What are unencapsulated receptors?
Receptors not covered by a glial or collagenous capsule.
p.36
Functions of the Skin
Is the warming effect of the arrector pili muscle significant in humans?
No, it is not very important in humans.
p.20
Dermis Composition and Function
What is the reticular region of the dermis?
The thicker deep part of the dermis.
p.27
Sensory Receptors in the Skin
Where are Meissner corpuscles located?
In the dermal papillae, perpendicular to the epidermis.
p.38
Glands: Sebaceous and Sweat Glands
What type of glands are sebaceous glands?
Simple branched acinar holocrine glands.
p.37
Hair Structure and Growth
What happens during the Anagen phase?
It is a generally long period of mitotic activity and growth.
p.24
Sensory Receptors in the Skin
Are there any parasympathetic nerves that supply the skin?
No, there are no parasympathetic nerves that supply the skin.
p.32
Hair Structure and Growth
What is the root of the hair?
The deeper part of the hair that reaches down into the dermis, surrounded by the hair follicle.
p.12
Epidermis Structure and Layers
What are squames?
Thin squamous cells that make up the stratum corneum, filled with keratin.
What are the three types of sensory functions of the skin?
Mechanical, thermal, and pain.
What is the primary protective function of the skin?
To act as a physical barrier against thermal and mechanical stresses and harmful substances.
p.36
Hair Structure and Growth
What happens to the arrector pili muscle under stressful conditions like cold?
It contracts, pulling the hair so that the shaft becomes perpendicular to the surface, producing 'goosebumps'.
p.36
Functions of the Skin
What physiological effect does the contraction of the arrector pili muscle have?
It helps to warm the body.
p.21
Dermis Composition and Function
What are tension lines?
Lines in the skin where collagen fibers orient due to natural tension.
p.27
Sensory Receptors in the Skin
What are Meissner corpuscles?
Encapsulated receptors responsible for the sensation of light touch.
p.3
Epidermis Structure and Layers
What are the main layers of the skin?
Epidermis, dermis, and subcutaneous tissue.
p.22
Dermis Composition and Function
What are the two vascular plexuses found in the dermis?
Subpapillary plexus and deep dermal plexus.
p.38
Glands: Sebaceous and Sweat Glands
Where are sebaceous glands found in relation to hair follicles?
In the angle between the arrector pili muscle and the hair follicle.
p.37
Hair Structure and Growth
What occurs during the Catagen phase?
A brief period of arrested growth and regression of the hair bulb.
p.24
Functions of the Skin
What is the primary function of the skin in relation to stimuli?
The skin functions as a receiver of various stimuli from the environment due to its large surface area and external location.
p.36
Hair Structure and Growth
What is the arrector pili muscle?
A bundle of smooth muscle cells that extends from the superficial part of the dermis to the dermal sheath of the hair follicle.
What is the primary function of the skin?
To protect the body from external factors.
p.19
Dermis Composition and Function
What is the dermis?
A connective tissue layer found under the epidermis.
p.39
Hair Structure and Growth
What is the pilosebaceous unit?
A structure that includes hair follicles and sebaceous glands.
p.29
Sensory Receptors in the Skin
What is the structure of Ruffini corpuscles?
They consist of a thin capsule attached to surrounding tissue, a fluid-filled interior, and an unmyelinated axon that branches profusely inside the capsule.
p.49
Nail Anatomy and Growth
Why do we clip fingernails more often than toenails?
Because fingernails grow at a faster rate.
p.43
Glands: Sebaceous and Sweat Glands
What does Fig. 22 (b) illustrate?
The types of cells in the secretory portion of eccrine sweat glands.
p.11
Epidermis Structure and Layers
Where are lamellar granules found?
In the stratum granulosum.
How does the skin protect against microorganisms?
By serving as a barrier that prevents their entry.
p.12
Epidermis Structure and Layers
What is the stratum corneum?
The most superficial layer of the skin.
p.40
Skin Cells: Keratinocytes, Melanocytes, and Others
What is acne vulgaris?
An inflammatory disorder of the pilosebaceous unit characterized by excessive keratinization and sebum production.
p.39
Hair Structure and Growth
What is the function of the arrector pili muscle?
It causes hair to stand up, contributing to goosebumps.
p.42
Glands: Sebaceous and Sweat Glands
What features distinguish clear cells?
Pale staining, numerous mitochondria, microvilli, and basal infoldings that increase surface area; they do not reach the lumen.
p.3
Dermis Composition and Function
What is the subcutaneous tissue primarily composed of?
Fat and connective tissue.
p.15
Functions of the Skin
How does melanin production affect vitamin D synthesis?
Increased melanin production can reduce vitamin D synthesis.
p.20
Dermis Composition and Function
What is the function of the arrector pili muscle found in the reticular region?
It causes hair to stand up (goosebumps) in response to cold or fear.
p.41
Glands: Sebaceous and Sweat Glands
What type of glands are sweat glands?
Simple coiled merocrine glands.
p.19
Dermis Composition and Function
What structures are contained in the papillary region of the dermis?
Blood capillary loops, lymphatic vessels, nerves, and Meissner’s corpuscles.
p.6
Epidermis Structure and Layers
How is skin classified histologically?
Into thin and thick skin based on epidermis thickness.
p.16
Skin Cells: Keratinocytes, Melanocytes, and Others
What type of receptors are Merkel cells?
Mechanoreceptors for light touch.
p.43
Glands: Sebaceous and Sweat Glands
What is depicted in Fig. 22 (a)?
An eccrine sweat gland, including its opening.
What is the significance of the 50th state of the USA?
Hawaii is the 50th state, admitted to the Union in 1959.
p.33
Hair Structure and Growth
What is the hair follicle?
A downward extension of the epidermis that surrounds the hair root.
p.18
Epidermis Structure and Layers
What is the primary function of the jigsaw-like arrangement of epidermal ridges and dermal papillae?
To increase the surface area of contact between the epidermis and dermis, reinforcing their junction.
What is histology?
The study of the microscopic structure of tissues.
p.18
Epidermis Structure and Layers
How do epidermal ridges affect tactile sensitivity?
They increase the density of Merkel cells and Meissner corpuscles, enhancing tactile sensitivity.
p.3
Dermis Composition and Function
What is the role of the dermis?
To provide strength and elasticity to the skin.
p.40
Skin Cells: Keratinocytes, Melanocytes, and Others
What leads to the blockage of the duct of the gland in acne vulgaris?
Excessive keratinization and sebum production.
p.32
Hair Structure and Growth
What are the three concentric layers of hair?
1) The medulla, 2) The cortex, 3) The cuticle.
p.37
Hair Structure and Growth
What characterizes the Telogen phase?
A long period of inactivity in which the hair may be shed.
p.32
Hair Structure and Growth
What is the medulla?
The innermost layer of hair composed of large, vacuolated cells.
p.12
Epidermis Structure and Layers
What happens to the most superficial cells of the stratum corneum?
They are continuously shed.
p.48
Nail Anatomy and Growth
What is the nail root formed from?
The nail matrix derived from the epidermis.
p.32
Hair Structure and Growth
What is the cuticle?
The outermost layer of hair formed of heavily keratinized squamous cells arranged like shingles on a house roof.
p.41
Glands: Sebaceous and Sweat Glands
How are eccrine sweat glands controlled?
By the sympathetic nervous system.
p.48
Nail Anatomy and Growth
Why does the lunula appear white?
Because of the opaque nail matrix under the lunula.
p.46
Glands: Sebaceous and Sweat Glands
What is the secretory portion structure of eccrine glands?
Small lumen with stratified epithelium.
p.11
Epidermis Structure and Layers
What do the lipids of the lamellar granules create when released by exocytosis?
A hydrophobic barrier that prevents water loss.
p.31
Hair Structure and Growth
Where are hairs not found on the body?
Palms, soles, lips, glans penis, clitoris, and labia minora.
p.29
Sensory Receptors in the Skin
What are Ruffini corpuscles?
Elongated fusiform structures found in the dermis that respond to stretch.
p.20
Dermis Composition and Function
What type of tissue forms the reticular region?
Dense collagenous irregular connective tissue.
p.25
Sensory Receptors in the Skin
What are sensory receptors in the skin responsible for?
Detecting various stimuli such as touch, temperature, and pain.
p.6
Epidermis Structure and Layers
What type of epithelium forms the epidermis?
Stratified squamous keratinized epithelium.
p.15
Functions of the Skin
What is the role of UV light in the skin?
It is required for the synthesis of vitamin D.
p.8
Epidermis Structure and Layers
What is the mitotic activity of cells in the stratum basale?
Highly mitotic; they are progenitor cells of all epidermal layers.
p.13
Skin Cells: Keratinocytes, Melanocytes, and Others
How is the cell body of melanocytes characterized?
Pale-staining and found between keratinocytes, not attached to them.
p.49
Nail Anatomy and Growth
Which grows faster, fingernails or toenails?
Fingernails grow at a faster rate than toenails.
p.26
Sensory Receptors in the Skin
What type of receptors are associated with epidermal tactile (Merkel) cells?
Tactile discs, which function as receptors for light touch.
p.31
Hair Structure and Growth
What factors influence hair distribution on the body?
Genetic factors, gender, and region of the body.
p.42
Glands: Sebaceous and Sweat Glands
What is the function of clear cells in the secretory portion?
They secrete the water and electrolyte components of sweat and take up interstitial fluid from the dermis.
p.15
Skin Cells: Keratinocytes, Melanocytes, and Others
What stimulates melanocytes to produce more melanin?
Exposure to sunlight (UV light).
p.33
Hair Structure and Growth
What happens to the internal root sheath?
It disappears above the level of the attached sebaceous gland.
p.25
Sensory Receptors in the Skin
How do sensory receptors contribute to the body's response to the environment?
They send signals to the brain to interpret sensations.
p.39
Glands: Sebaceous and Sweat Glands
What do sebocytes look like histologically?
They have a white appearance.
p.25
Sensory Receptors in the Skin
What role do mechanoreceptors play in the skin?
They respond to mechanical pressure or distortion.
p.22
Thermoregulation and Vascular Supply of the Skin
How does blood flow to the subpapillary plexus change in cold conditions?
It is reduced to decrease heat loss.
p.40
Skin Cells: Keratinocytes, Melanocytes, and Others
What is the current understanding of Demodex folliculorum's role in skin disorders?
It is thought to be implicated in some skin disorders, but nothing is conclusive yet.
p.38
Glands: Sebaceous and Sweat Glands
What functions does sebum serve?
Helps maintain the stratum corneum and hair shaft, and has some antibacterial effect.
p.6
Epidermis Structure and Layers
What does total skin thickness include?
The thickness of both the epidermis and dermis.
p.44
Glands: Sebaceous and Sweat Glands
Do apocrine sweat glands produce pheromones?
Yes, but in a reduced manner.
p.46
Glands: Sebaceous and Sweat Glands
What is a function of apocrine glands?
Stimulated during emotional stress.
p.37
Hair Structure and Growth
What are the three phases of hair growth?
Anagen, Catagen, and Telogen.
p.47
Nail Anatomy and Growth
What are nails primarily composed of?
Hard plates of keratinized cells.
p.14
Skin Cells: Keratinocytes, Melanocytes, and Others
Where are melanocytes located?
Within the stratum basale (SB).
p.20
Dermis Composition and Function
What key components are found in the reticular region?
Collagen and elastic fibers, lymphatic and blood vessel plexuses, sensory receptors and nerves, hair follicles, arrector pili muscle, and glands.
p.1
Epidermis Structure and Layers
What are the main layers of the skin?
Epidermis, dermis, and hypodermis.
p.18
Epidermis Structure and Layers
What effect do epidermal ridges have on grip?
They increase the surface area of grip on hands or feet by enhancing friction.
p.9
Epidermis Structure and Layers
Why do the cells in the stratum spinosum appear spiny?
Because when the tissue is prepared, the cells shrink, revealing desmosomes and tonofibrils.
p.1
Skin Cells: Keratinocytes, Melanocytes, and Others
What role do melanocytes play in the skin?
They produce melanin, which gives skin its color and protects against UV radiation.
p.6
Epidermis Structure and Layers
Name three other types of cells found in the epidermis.
Melanocytes, Merkel cells, and Langerhans cells.
p.28
Sensory Receptors in the Skin
Where are Lamellated (Pacinian) corpuscles located?
Deep in the reticular dermis and hypodermis.
p.34
Hair Structure and Growth
What type of tissue is found in the hair dermal papilla?
Loose areolar connective tissue and blood vessels.
p.41
Glands: Sebaceous and Sweat Glands
What is the structure of the secretory portion of eccrine sweat glands?
It has a small lumen with a stratified arrangement of cells.
p.2
Skin Cells: Keratinocytes, Melanocytes, and Others
What structures are found in the skin?
Sensory organs, arrector pili muscle, hair, nails, sebaceous and sweat glands, mammary glands.
p.44
Glands: Sebaceous and Sweat Glands
What type of secretion do apocrine sweat glands produce?
A viscous protein-rich secretion.
p.42
Glands: Sebaceous and Sweat Glands
What are the characteristics of dark cells in the secretory portion?
Inverted-cone-shaped, reach the lumen but do not rest on the basal lamina, contain mitochondria, Golgi apparatus, and rough endoplasmic reticulum, filled with eosinophilic granules, and release glycoproteins by exocytosis.
p.24
Sensory Receptors in the Skin
Which structures in the skin are supplied by postganglionic sympathetic nerves?
Sweat glands, the arrector pili muscle, and blood vessels.
p.12
Epidermis Structure and Layers
How many layers of cells does the stratum corneum typically have?
15-20 layers of thin squamous cells called squames.
p.47
Nail Anatomy and Growth
Where are nails located on the body?
On the dorsal surface of the distal phalanges.
p.45
Glands: Sebaceous and Sweat Glands
What distinguishes the secretory portion of an apocrine sweat gland from an eccrine sweat gland?
The apocrine sweat gland has a larger lumen.
p.47
Nail Anatomy and Growth
What surrounds the nail plate (body)?
Three skin folds: medial, lateral, and proximal.
p.19
Dermis Composition and Function
What characterizes the papillary region of the dermis?
It is a thin, superficial part corresponding to the dermal papillae.
p.22
Dermis Composition and Function
What do capillary loops from the subpapillary plexus supply?
Nutrients to the epidermis.
p.27
Sensory Receptors in the Skin
Where are Meissner corpuscles most numerous?
In the fingertips, palms, and soles.
p.19
Dermis Composition and Function
What type of connective tissue forms the papillary region?
Loose areolar connective tissue.
p.29
Sensory Receptors in the Skin
What is the structure of Krause end bulbs?
Ovoid structures with an extremely thin capsule.
p.38
Glands: Sebaceous and Sweat Glands
Where does the duct of sebaceous glands open?
Into the hair follicle, or directly onto the epidermal surface in hairless regions.
p.14
Functions of the Skin
What factors contribute to the color of the skin?
Melanin pigment, carotene pigment, and blood in the vessels.
p.44
Glands: Sebaceous and Sweat Glands
Where are apocrine sweat glands primarily found?
In the axillary and perineal regions.
p.2
Dermis Composition and Function
What is the hypodermis?
A fatty layer that connects the skin to underlying tissues.
p.10
Epidermis Structure and Layers
How do Lamellar Granules appear under an electron microscope?
As oval structures with several lamellae.
p.32
Hair Structure and Growth
What is the shaft of the hair?
The superficial part of the hair that extends beyond the surface of the skin.
What does the skin prevent in terms of water loss?
Excessive loss of water through the skin.
p.29
Sensory Receptors in the Skin
Where are Krause end bulbs found?
In the skin of the penis and clitoris, several mucous membranes, and in the epineurium of nerves.
What role does the lipid-rich layer of the skin play?
It makes the skin a selectively permeable membrane, allowing lipophilic substances to pass while preventing water loss.
p.30
Functions of the Skin
What is one of the main functions of the subcutaneous layer?
Enables the skin to slide over underlying structures.
p.24
Sensory Receptors in the Skin
What types of sensory receptors are found in the skin?
Sensory receptors in the skin can be either encapsulated by glial and collagenous coverings or unencapsulated.
Why is the skin's function important for terrestrial life?
It allows organisms to live on land without needing to be submerged in water.
p.30
Functions of the Skin
How does fat in the subcutaneous layer function?
As an energy storage site, insulator, and shock absorber.
p.18
Epidermis Structure and Layers
What do sweat and epidermal ridges form when a smooth object is touched?
Fingerprints or footprints.
p.19
Sensory Receptors in the Skin
What are Meissner’s corpuscles?
Sensory receptors responsible for the sense of touch.
p.15
Skin Cells: Keratinocytes, Melanocytes, and Others
Will Ahmed's tan change his skin color permanently?
No, it will return to its usual complexion over time.
p.34
Hair Structure and Growth
What is the hair matrix formed of?
Keratinocytes continuous with the stratum basale of the epidermis.
p.44
Glands: Sebaceous and Sweat Glands
What is the structure of the secretory portion of apocrine sweat glands?
It has a large lumen with simple cuboidal eosinophilic cells.
p.44
Glands: Sebaceous and Sweat Glands
What was the initial belief about how apocrine sweat glands release their secretions?
They were thought to be apocrine and named so, but they actually release by exocytosis.
p.19
Dermis Composition and Function
What are the two sublayers of the dermis?
The papillary region and the reticular region.
p.9
Epidermis Structure and Layers
What happens to keratin filaments in the stratum spinosum?
They become thick tonofibrils attached to desmosomes.
p.33
Hair Structure and Growth
How does the external root sheath connect to the epidermis?
It becomes continuous with the stratum basale and spinosum.
p.22
Dermis Composition and Function
What is the role of anastomoses between the two plexuses?
They are important for the thermoregulatory function of the skin.
p.10
Epidermis Structure and Layers
What do Keratohyaline Granules contain?
Keratins and tonofilaments associated with proteins.
p.12
Epidermis Structure and Layers
What are calluses?
Areas of thickened stratum corneum due to repeated friction.
p.16
Skin Cells: Keratinocytes, Melanocytes, and Others
What is the basal surface of Merkel cells in contact with?
The expanded terminal of an unmyelinated nerve fiber.
p.46
Glands: Sebaceous and Sweat Glands
What controls apocrine gland activity?
Nervous (adrenergic) and hormonal control.
p.22
Dermis Composition and Function
Where is the subpapillary plexus located?
Between the papillary and reticular regions of the dermis.
p.16
Skin Cells: Keratinocytes, Melanocytes, and Others
What are Langerhans cells?
Antigen-presenting cells found mainly in the stratum spinosum.
p.13
Skin Cells: Keratinocytes, Melanocytes, and Others
Where are melanocytes located?
In the stratum basale and hair follicles.
p.17
Epidermis Structure and Layers
What is the significance of the interdigitation between the dermis and epidermis in thick skin?
It creates a pattern of grooves and ridges, which are the basis of fingerprints.
What is the first step in the treatment of extensive burns?
The question is not answered in the provided text.
p.1
Dermis Composition and Function
What is the function of the dermis?
It provides strength and elasticity to the skin and houses blood vessels, nerves, and glands.
p.28
Sensory Receptors in the Skin
What are the main components of Lamellated (Pacinian) corpuscles?
Fibrous capsule, layers of connective tissue, concentric layers of flattened Schwann cells, and a sensory fiber in the center.
p.16
Skin Cells: Keratinocytes, Melanocytes, and Others
Where are Merkel cells located?
Between the cells of the stratum basale.
p.2
Epidermis Structure and Layers
What are the two main layers that form the skin?
The epidermis and dermis.
p.13
Skin Cells: Keratinocytes, Melanocytes, and Others
How do keratinocytes interact with melanosomes?
Keratinocytes engulf the tips of melanocyte processes where melanosomes are located.
p.44
Glands: Sebaceous and Sweat Glands
Where does the duct of apocrine sweat glands open?
Into the hair follicle near the epidermis.
p.44
Glands: Sebaceous and Sweat Glands
What causes the distinctive odor associated with body odor?
Bacteria acting on the secretion from apocrine sweat glands.
p.23
Thermoregulation and Vascular Supply of the Skin
What is the primary function of vascular plexuses in the skin?
To regulate blood flow and thermoregulation.
Where is energy stored as fat in the skin?
In the subcutaneous layer.
p.16
Skin Cells: Keratinocytes, Melanocytes, and Others
What is the primary function of Langerhans cells?
To bind and present antigens to lymphocytes, playing an important immune role.
p.30
Functions of the Skin
What advantage does the rich vasculature in the subcutaneous layer provide?
Enables rapid intake of drugs injected into this layer.
p.18
Epidermis Structure and Layers
Why can the pattern of epidermal ridges be used for identification?
Because the pattern is genetically determined.
p.48
Nail Anatomy and Growth
What happens as more cells are added to the nail root?
The root grows and the plate extends distally over the nail bed.
p.41
Glands: Sebaceous and Sweat Glands
What is the primary role of eccrine sweat glands?
Thermoregulation and some excretory function.
p.44
Glands: Sebaceous and Sweat Glands
What controls the activity of apocrine sweat glands?
The sympathetic nervous system and sex hormones.
p.10
Epidermis Structure and Layers
What happens to the contents of Keratohyaline Granules?
Contents remain in the cell.
p.10
Epidermis Structure and Layers
What happens to the contents of Lamellar Granules?
Contents are released to the outside of the cell.
p.48
Nail Anatomy and Growth
What is the free edge of the nail adhered to the fingertip by?
A fold of epidermis called the hyponychium.
p.46
Glands: Sebaceous and Sweat Glands
What is the secretory portion structure of apocrine glands?
Large lumen with simple epithelium.
p.25
Sensory Receptors in the Skin
Name a type of sensory receptor found in the skin.
Mechanoreceptors, thermoreceptors, or nociceptors.
p.39
Glands: Sebaceous and Sweat Glands
What is the histological appearance of the sebaceous gland characterized by?
A capsule and the white appearance of sebocytes.
p.20
Dermis Composition and Function
What role do collagen and elastic fibers play in the reticular region?
They provide strength and elasticity to the skin.
p.18
Glands: Sebaceous and Sweat Glands
Where do the ducts of sweat glands open?
On the tops of the surface epidermal ridges as sweat pores.
p.10
Epidermis Structure and Layers
What types of granules are found in the Stratum granulosum?
Keratohyaline Granules and Lamellar Granules.
p.33
Hair Structure and Growth
What is the dermal root sheath derived from?
The connective tissue of the dermis.
p.25
Sensory Receptors in the Skin
What is the function of nociceptors?
They detect pain and harmful stimuli.
p.22
Dermis Composition and Function
What do lymphatic vessels form in the dermis?
Two plexuses located with the blood vessels.
p.34
Hair Structure and Growth
What do melanocytes in the hair matrix do?
They give hair its color.
p.13
Skin Cells: Keratinocytes, Melanocytes, and Others
What is the function of the supranuclear cap formed by melanosomes?
To protect DNA from harmful effects of UV light.
p.46
Glands: Sebaceous and Sweat Glands
What controls eccrine gland activity?
Nervous (cholinergic) control.
p.14
Skin Cells: Keratinocytes, Melanocytes, and Others
What do a melanocyte and its associated keratinocytes form?
An epidermal-melanin unit.
p.15
Functions of the Skin
Is there a difference in vitamin D levels between fair-skinned and dark-complexioned individuals?
Yes, there can be a difference due to varying melanin levels.
p.40
Skin Cells: Keratinocytes, Melanocytes, and Others
What is Demodex folliculorum?
A small mite that lives in the hair follicle and feeds on dead cells and sebum.
p.14
Skin Cells: Keratinocytes, Melanocytes, and Others
What differs among individuals regarding melanin production?
The rate and amount of production.
p.13
Skin Cells: Keratinocytes, Melanocytes, and Others
What organelles are found in the cytoplasm of melanocytes?
Mitochondria, rough endoplasmic reticulum, and Golgi apparatus.
p.46
Glands: Sebaceous and Sweat Glands
Where are eccrine glands located?
All over the body, especially on palms and soles.
p.46
Glands: Sebaceous and Sweat Glands
Where are apocrine glands primarily found?
In the axillary and perineal regions.
p.41
Glands: Sebaceous and Sweat Glands
What do the duct cells of eccrine sweat glands absorb?
Na+ ions to prevent excessive loss of this electrolyte.
What is the role of the skin in relation to the environment?
It serves as the boundary between the internal and external environment of the body.
p.42
Glands: Sebaceous and Sweat Glands
What role do myoepithelial cells play in sweat glands?
They rest on the basal lamina and contract to help push sweat into the ducts.
p.33
Hair Structure and Growth
What is the glassy membrane?
The thickened basement membrane that separates the epithelial and dermal root sheaths.
p.32
Hair Structure and Growth
What is the cortex?
The middle layer of hair made up of cuboidal cells.
p.22
Thermoregulation and Vascular Supply of the Skin
How does blood flow to the subpapillary plexus change in hot conditions?
It is increased to facilitate heat loss.
p.47
Nail Anatomy and Growth
What is the eponychium?
The cuticle that continues distally over the nail.
p.28
Sensory Receptors in the Skin
What sensations are Lamellated (Pacinian) corpuscles responsible for?
Deep touch, pressure, and vibration.
p.8
Epidermis Structure and Layers
What happens to keratinocytes as they mature in the stratum basale?
They migrate upwards until they reach the surface where they are shed.
p.48
Nail Anatomy and Growth
What layers form the thin nail bed?
Stratum basale and stratum spinosum.
p.48
Nail Anatomy and Growth
Why can the color of blood in dermal vessels be seen through the nail?
Because the mature nail plate is semitransparent.
What is another name for the skin?
Cutaneous layer or integument.
p.46
Glands: Sebaceous and Sweat Glands
Where do eccrine glands open?
Usually on the surface of the skin.
p.47
Nail Anatomy and Growth
How does the stratum corneum behave at the proximal nail fold?
It doesn’t pass with the other layers of the epidermis but continues over the nail as the eponychium.
p.28
Sensory Receptors in the Skin
Can Lamellated (Pacinian) corpuscles be found in other organs?
Yes, they may be found in other organs.
p.10
Epidermis Structure and Layers
How do Keratohyaline Granules appear under a light microscope?
As basophilic structures.
