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What prevents backflow of lymph in lymphatic vessels? A) Smooth muscle contractions B) Valves comprised of complete intimal folds C) High pressure in the lymphatic system D) Presence of red blood cells E) Thick walls of the vessels
B) Valves comprised of complete intimal folds Explanation: Lymphatic vessels have valves that prevent backflow of lymph, ensuring unidirectional flow similar to veins.
What is the primary function of the portal vein in the circulatory system? A) To transport oxygenated blood to the heart B) To connect two capillary beds for efficient nutrient delivery C) To drain lymphatic fluid from tissues D) To regulate blood pressure in arteries E) To supply blood to the lungs
B) To connect two capillary beds for efficient nutrient delivery Explanation: The portal vein connects two successive capillary beds, allowing for efficient delivery of hormones or nutrients to cells before the blood returns to the heart.
1/67
p.10
Lymphatic Vascular System

What prevents backflow of lymph in lymphatic vessels?
A) Smooth muscle contractions
B) Valves comprised of complete intimal folds
C) High pressure in the lymphatic system
D) Presence of red blood cells
E) Thick walls of the vessels

B) Valves comprised of complete intimal folds
Explanation: Lymphatic vessels have valves that prevent backflow of lymph, ensuring unidirectional flow similar to veins.

p.2
Microvascular Pathways

What is the primary function of the portal vein in the circulatory system?
A) To transport oxygenated blood to the heart
B) To connect two capillary beds for efficient nutrient delivery
C) To drain lymphatic fluid from tissues
D) To regulate blood pressure in arteries
E) To supply blood to the lungs

B) To connect two capillary beds for efficient nutrient delivery
Explanation: The portal vein connects two successive capillary beds, allowing for efficient delivery of hormones or nutrients to cells before the blood returns to the heart.

p.2
Capillary Structure and Function

What is the primary characteristic of true capillaries?
A) They contain smooth muscle cells
B) They are larger than arterioles
C) They lack smooth muscle cells
D) They are only found in the lungs
E) They have thick walls for strength

C) They lack smooth muscle cells
Explanation: True capillaries are characterized by the absence of smooth muscle cells, allowing for efficient exchange of substances between blood and surrounding tissues.

p.1
Microvascular Pathways

What is the function of arteriovenous shunts?
A) To increase blood pressure
B) To bypass capillary networks
C) To decrease blood flow to the heart
D) To enhance nutrient absorption
E) To regulate blood viscosity

B) To bypass capillary networks
Explanation: Arteriovenous shunts allow blood to bypass capillary networks, connecting arterioles directly to venules, which is crucial for regulating blood flow and thermoregulation.

p.1
Arterioles and Blood Flow

What is a characteristic of muscular arteries?
A) They have more elastin than smooth muscle
B) They are primarily composed of connective tissue
C) They have thicker smooth muscle layers than elastic lamellae
D) They are only found in the heart
E) They do not have an internal elastic lamina

C) They have thicker smooth muscle layers than elastic lamellae
Explanation: Muscular arteries are characterized by having multiple layers of smooth muscle in their media, which are thicker than the elastic lamellae, allowing for greater control of blood flow.

p.6
Capillary Structure and Function

What distinguishes sinusoidal capillaries from other types?
A) They have a continuous basal lamina
B) They have much greater diameters and allow blood cells to move easily
C) They are only found in the brain
D) They are the smallest type of capillary
E) They have no fenestrations

B) They have much greater diameters and allow blood cells to move easily
Explanation: Sinusoidal capillaries, or sinusoids, are characterized by their larger diameters and specialized structure that facilitates maximal molecular exchange and easy movement of blood cells across the endothelium.

p.12
Hypertension Causes

The disease process in the patient with exercise-induced angina initially involved which one of the following?
A) Smooth muscle cell proliferation
B) Formation of an intimal plaque
C) Intimal thickening through addition of collagen and elastin
D) Adventitial proliferation of fibroblasts
E) Injury to endothelial cells

E) Injury to endothelial cells
Explanation: The initial step in the development of atherosclerosis, which can lead to angina, often involves injury to the endothelial cells lining the blood vessels.

p.11
Lymphatic Vascular System

What is the function of the cardiac conducting system?
A) To supply blood to the heart
B) To stimulate rhythmic contractions
C) To provide structural support
D) To regulate blood pressure
E) To transport oxygen

B) To stimulate rhythmic contractions
Explanation: The cardiac conducting system is responsible for stimulating rhythmic contractions of the heart, ensuring proper blood flow and heart function.

p.10
Lymphatic Vascular System

What role do lymph nodes play in the lymphatic system?
A) They produce red blood cells
B) They process lymph with immune system cells
C) They store excess nutrients
D) They filter blood
E) They regulate blood pressure

B) They process lymph with immune system cells
Explanation: Lymph nodes are interposed in the path of larger lymphatic vessels and are responsible for processing lymph through immune system cells.

p.7
Venous System Structure

What is a key characteristic of the tunica intima in large veins?
A) It is thick and muscular
B) It is usually thin
C) It contains a high number of elastic fibers
D) It is absent in large veins
E) It is primarily made of connective tissue

B) It is usually thin
Explanation: The tunica intima in large veins is usually thin, which differentiates it from the thicker layers found in arteries.

p.8
Lymphatic Vascular System

What is the primary function of lymphatic capillaries?
A) To transport oxygenated blood
B) To collect excess interstitial fluid as lymph
C) To deliver nutrients to tissues
D) To remove carbon dioxide from the blood
E) To store blood cells

B) To collect excess interstitial fluid as lymph
Explanation: Lymphatic capillaries are responsible for collecting excess interstitial fluid from tissue spaces and returning it to the blood, playing a crucial role in fluid balance in the body.

p.9
Lymphatic Vascular System

What prevents backflow of lymph into tissue spaces?
A) Blood cells
B) Anchoring filaments
C) Endothelial folds
D) Smooth muscle
E) Valves in veins

C) Endothelial folds
Explanation: The endothelial folds in lymphatic capillaries prevent the backflow of lymph into tissue spaces, ensuring unidirectional flow towards the lymphatic system.

p.7
Microvascular Pathways

What is the primary function of postcapillary venules in the context of inflammation?
A) To transport oxygen
B) To allow white blood cells to exit circulation
C) To absorb nutrients
D) To regulate blood pressure
E) To store blood

B) To allow white blood cells to exit circulation
Explanation: Postcapillary venules are important as the site where white blood cells leave the circulation to become functional in surrounding tissues during inflammation or infection.

p.2
Microvascular Pathways

Which of the following systems is an example of a portal system?
A) Pulmonary circulation
B) Hepatic portal system
C) Coronary circulation
D) Systemic circulation
E) Renal circulation

B) Hepatic portal system
Explanation: The hepatic portal system is a well-known example of a portal system that connects the capillary beds of the gastrointestinal tract to the liver.

p.12
Pericytes and Their Functions

Which of the following is true of pericytes?
A) Are associated with the basal lamina of capillary endothelial cells
B) Have similar histological features as contractile cells of the myocardium
C) Form a layer of cells joined by gap junctions
D) Are terminally differentiated
E) Capable of forming multinucleated muscle fibers

A) Are associated with the basal lamina of capillary endothelial cells
Explanation: Pericytes are located on the outside of capillary endothelial cells and are associated with the basal lamina, playing a role in vascular stability and regulation.

p.10
Lymphatic Vascular System

Where do lymphatic vessels ultimately converge?
A) Into the heart
B) Into the lungs
C) Into the thoracic duct and right lymphatic duct
D) Into the liver
E) Into the kidneys

C) Into the thoracic duct and right lymphatic duct
Explanation: Lymphatic vessels converge into two large trunks, the thoracic duct and the right lymphatic duct, which return lymph to the bloodstream.

p.10
Medical Applications of Vascular Knowledge

What can result from the surgical removal of lymph nodes?
A) Increased blood pressure
B) Lymphedema in the affected region
C) Enhanced immune response
D) Decreased lymphocyte distribution
E) Improved lymphatic drainage

B) Lymphedema in the affected region
Explanation: Surgical removal of lymph nodes can disrupt lymphatic drainage, leading to swelling or lymphedema in the tissues of the affected area.

p.9
Lymphatic Vascular System

What is the composition of lymph?
A) Rich in red blood cells
B) Rich in proteins and other materials
C) Primarily composed of glucose
D) Contains only water
E) High in carbon dioxide

B) Rich in proteins and other materials
Explanation: Lymph is rich in proteins and other materials, which distinguishes it from blood plasma and contributes to its staining properties.

p.8
Microvascular Pathways

What is a consequence of the loosest junctions between endothelial cells of postcapillary venules?
A) Increased blood pressure
B) Enhanced nutrient delivery
C) Facilitation of leukocyte migration during inflammation
D) Decreased fluid loss
E) Reduced oxygen exchange

C) Facilitation of leukocyte migration during inflammation
Explanation: The loose junctions between endothelial cells in postcapillary venules facilitate the trans-endothelial migration of leukocytes during inflammation, contributing to the immune response.

p.3
Microvascular Pathways

What is a characteristic of arteriovenous (AV) shunts?
A) They connect arteries to capillaries
B) They allow blood to bypass capillaries
C) They are found only in the liver
D) They drain directly into venules
E) They are responsible for nutrient absorption

B) They allow blood to bypass capillaries
Explanation: Arteriovenous shunts connect the arterial and venous systems directly, allowing blood to bypass capillaries, which is important for regulating blood flow in response to external conditions.

p.4
Capillary Structure and Function

What is a key feature of fenestrated capillaries?
A) They have no openings
B) They are completely solid
C) They have small circular openings called fenestrations
D) They are found only in the skin
E) They are the largest type of capillary

C) They have small circular openings called fenestrations
Explanation: Fenestrated capillaries have numerous small circular openings (fenestrations) that allow for more extensive molecular exchange, making them suitable for organs with rapid interchange of substances.

p.10
Lymphatic Vascular System

What is the primary function of lymphatic capillaries?
A) To transport oxygenated blood
B) To facilitate the entry of interstitial fluid
C) To store red blood cells
D) To produce hormones
E) To absorb nutrients from the digestive tract

B) To facilitate the entry of interstitial fluid
Explanation: Lymphatic capillaries allow interstitial fluid to enter by flowing between endothelial cells and through transcytosis, playing a crucial role in the lymphatic system's function.

p.7
Venous System Structure

What type of cells are found in postcapillary venules?
A) Only smooth muscle cells
B) Only endothelial cells
C) Endothelial cells and pericytes
D) Only leukocytes
E) Only collagen fibers

C) Endothelial cells and pericytes
Explanation: Postcapillary venules have an intima of simple endothelial cells with occasional pericytes, which play a role in the vascular structure.

p.1
Blood Pressure Regulation

What primarily determines blood pressure in the circulatory system?
A) Cardiac output and total peripheral resistance
B) Heart rate and blood volume
C) Blood viscosity and vessel diameter
D) Oxygen levels and carbon dioxide levels
E) Temperature and pH levels

A) Cardiac output and total peripheral resistance
Explanation: Blood pressure is fundamentally dependent on cardiac output and the total peripheral resistance to blood flow, with arterioles playing a significant role in this resistance.

p.1
Hypertension Causes

What is essential hypertension primarily caused by?
A) Genetic factors only
B) Renal problems
C) Endocrine problems
D) Increased arteriolar constriction
E) High blood volume

D) Increased arteriolar constriction
Explanation: Essential hypertension is commonly due to various mechanisms that increase arteriolar constriction, rather than being solely linked to renal or endocrine issues.

p.2
Capillary Structure and Function

What role do precapillary sphincters play in capillary beds?
A) They increase blood pressure
B) They regulate blood flow into true capillaries
C) They transport oxygen to tissues
D) They drain excess interstitial fluid
E) They connect arterioles to venules

B) They regulate blood flow into true capillaries
Explanation: Precapillary sphincters control the flow of blood into true capillaries, allowing for efficient exchange of nutrients and wastes.

p.2
Capillary Structure and Function

What happens to blood flow when precapillary sphincters are contracted?
A) Blood flows freely into capillaries
B) Blood is shunted away from the capillary bed
C) Blood pressure increases significantly
D) Blood becomes poorly oxygenated
E) Blood enters the venous system directly

B) Blood is shunted away from the capillary bed
Explanation: When precapillary sphincters are contracted, blood is redirected away from the capillary bed, reducing perfusion and nutrient exchange.

p.6
Capillary Structure and Function

Where are fenestrated capillaries commonly found?
A) In the lungs
B) In the skin
C) In the intestinal wall, kidneys, and endocrine glands
D) In the heart
E) In the brain

C) In the intestinal wall, kidneys, and endocrine glands
Explanation: Fenestrated capillaries are specifically found in areas requiring rapid exchange of substances, such as the intestinal wall, kidneys, and endocrine glands.

p.3
Microvascular Pathways

What is the function of precapillary sphincters?
A) To increase blood pressure
B) To control blood flow into capillaries
C) To drain blood from venules
D) To connect arterioles to venules
E) To supply blood to the heart

B) To control blood flow into capillaries
Explanation: Precapillary sphincters, located in the metarterioles, regulate blood flow into capillaries by contracting and relaxing, thus controlling the distribution of blood based on tissue needs.

p.9
Lymphatic Vascular System

What is the primary function of lymphatic capillaries?
A) To transport oxygenated blood
B) To drain interstitial fluid
C) To absorb nutrients from the digestive tract
D) To produce red blood cells
E) To filter toxins from the blood

B) To drain interstitial fluid
Explanation: Lymphatic capillaries are responsible for draining interstitial fluid that is produced when plasma is forced from the microvasculature, ensuring that excess fluid is returned to the circulatory system.

p.8
Venous System Structure

How are veins classified?
A) By their color
B) By their size and development of tunics
C) By their location in the body
D) By the type of blood they carry
E) By their length

B) By their size and development of tunics
Explanation: Veins are classified as small, medium, or large based on their size and the development of their tunics, which reflects their structural characteristics.

p.6
Capillary Structure and Function

What is the primary function of fenestrated capillaries?
A) To transport oxygen
B) For uptake of molecules such as hormones
C) To provide structural support
D) For blood storage
E) To regulate blood pressure

B) For uptake of molecules such as hormones
Explanation: Fenestrated capillaries are specialized for the uptake of molecules like hormones in endocrine glands and for the outflow of molecules in the kidney’s filtration system, allowing for freer exchange than continuous capillaries.

p.3
Microvascular Pathways

What are metarterioles primarily responsible for?
A) Supplying blood to the heart
B) Connecting arteries to veins
C) Supplying capillary beds
D) Draining blood from capillaries
E) Forming arterial portal systems

C) Supplying capillary beds
Explanation: Metarterioles are terminal branches that supply capillary beds, playing a crucial role in regulating blood flow to tissues with varying metabolic rates.

p.1
Microvascular Pathways

What do glomus bodies detect in the blood?
A) Blood pressure changes
B) Blood chemistry changes
C) Temperature changes
D) Blood flow rate
E) Oxygen saturation levels

B) Blood chemistry changes
Explanation: Glomus bodies act as chemoreceptors that provide information to the brain regarding significant changes in blood CO2, O2, or H+ concentrations.

p.4
Capillary Structure and Function

What is the average diameter of capillaries?
A) 1 to 2 μm
B) 4 to 10 μm
C) 10 to 20 μm
D) 20 to 30 μm
E) 30 to 40 μm

B) 4 to 10 μm
Explanation: The average diameter of capillaries varies from 4 to 10 μm, which is crucial for allowing blood cells to transit one at a time through these small vessels.

p.5
Capillary Structure and Function

What is the primary function of continuous capillaries?
A) To allow free passage of all molecules
B) To exert tight control over what molecules leave and enter the capillary lumen
C) To facilitate the exchange of macromolecules
D) To provide structural support to blood vessels
E) To store blood cells

B) To exert tight control over what molecules leave and enter the capillary lumen
Explanation: Continuous capillaries are designed to tightly regulate the exchange of substances, ensuring that only specific molecules can pass through, primarily via diffusion or transcytosis.

p.11
Lymphatic Vascular System

What is the primary function of the vasa vasorum?
A) To supply blood to the heart
B) To prevent backflow in veins
C) To provide nutrients to the walls of larger vessels
D) To facilitate lymph drainage
E) To regulate blood pressure

C) To provide nutrients to the walls of larger vessels
Explanation: The vasa vasorum serves to supply nutrients and oxygen to the walls of larger blood vessels, ensuring their health and functionality.

p.7
Venous System Structure

What feature is particularly important in large and medium veins?
A) Thick tunica media
B) Valves
C) High oxygen content
D) Absence of smooth muscle
E) Presence of capillaries

B) Valves
Explanation: Valves are an important feature of large and medium veins, helping to direct the flow of venous blood toward the heart, especially in the legs.

p.8
Venous System Structure

What is a key structural feature of small veins?
A) Thick muscular walls
B) Large lumen compared to arteries
C) Presence of valves
D) Multiple layers of smooth muscle
E) Thick adventitia

B) Large lumen compared to arteries
Explanation: Small veins have a relatively large lumen compared to small muscular arteries, and their walls are very thin, containing only two or three layers of smooth muscle.

p.12
Lymphatic Vascular System

What likely caused the lymph edema in the patient after mastectomy?
A) Angiogenesis from arterial branches that brought blood to the left breast
B) Growth of cancer cells and blockage of lymphatic drainage from the left arm
C) Surgical disruption of the left arm’s lymphatic drainage by removal of lymph nodes
D) Surgical damage to the thoracic duct during lymph node removal
E) Hypertrophy of the vessels in the upper arm to accommodate blood otherwise flowing to the left breast

C) Surgical disruption of the left arm’s lymphatic drainage by removal of lymph nodes
Explanation: The removal of lymph nodes during surgery can disrupt normal lymphatic drainage, leading to lymph edema in the affected area.

p.6
Pericytes and Their Functions

What role do pericytes play in the circulatory system?
A) They transport oxygen
B) They regulate blood flow and help maintain the blood-brain barrier
C) They produce red blood cells
D) They are responsible for blood clotting
E) They store nutrients

B) They regulate blood flow and help maintain the blood-brain barrier
Explanation: Pericytes are mesenchymal cells that surround capillaries, regulating blood flow and playing a crucial role in maintaining the endothelial blood-brain barrier, as well as contributing to tissue regeneration.

p.4
Capillary Structure and Function

What is the primary function of discontinuous capillaries (sinusoids)?
A) To prevent any exchange of substances
B) To allow maximal exchange of macromolecules and easier movement of cells
C) To regulate blood pressure
D) To transport oxygen only
E) To filter blood

B) To allow maximal exchange of macromolecules and easier movement of cells
Explanation: Discontinuous capillaries, or sinusoids, permit maximal exchange of macromolecules and facilitate easier movement of cells between tissues and blood, making them essential in certain organs.

p.9
Lymphatic Vascular System

What is the diameter range of lymphatic capillaries?
A) 1-5 μm
B) 5-10 μm
C) 10-50 μm
D) 50-100 μm
E) 100-200 μm

C) 10-50 μm
Explanation: Lymphatic capillaries have a variable diameter ranging from 10 to 50 μm, which allows them to accommodate the flow of lymph.

p.9
Lymphatic Vascular System

What type of cells primarily compose the walls of lymphatic capillaries?
A) Smooth muscle cells
B) Epithelial cells
C) Endothelial cells
D) Fibroblasts
E) Adipocytes

C) Endothelial cells
Explanation: The walls of lymphatic capillaries are composed of very thin endothelial cells, which lack tight junctions and allow for the entry of interstitial fluid.

p.8
Venous System Structure

What role do valves in veins play?
A) To increase blood pressure
B) To prevent backflow of blood
C) To enhance nutrient absorption
D) To facilitate oxygen exchange
E) To regulate blood flow speed

B) To prevent backflow of blood
Explanation: Valves in veins are thin folds of intima that project into the lumen, preventing the backflow of blood and ensuring unidirectional flow towards the heart.

p.5
Capillary Structure and Function

What type of capillary has tight, occluding junctions that minimize fluid leakage?
A) Fenestrated capillaries
B) Sinusoids
C) Continuous capillaries
D) Discontinuous capillaries
E) Arterioles

C) Continuous capillaries
Explanation: Continuous capillaries are characterized by tight, occluding junctions that seal the intercellular clefts, allowing minimal fluid leakage and controlling the exchange of molecules through diffusion or transcytosis.

p.5
Capillary Structure and Function

Which type of capillary allows for greater molecular exchange due to the presence of fenestrations?
A) Continuous capillaries
B) Sinusoids
C) Fenestrated capillaries
D) Discontinuous capillaries
E) Venules

C) Fenestrated capillaries
Explanation: Fenestrated capillaries have perforations (fenestrations) that facilitate greater exchange of molecules across the endothelium, making them suitable for organs where molecular exchange is crucial.

p.4
Capillary Structure and Function

What percentage of total blood volume is typically moving through capillaries at any given time?
A) 10%
B) 25%
C) 50%
D) 5%
E) 75%

D) 5%
Explanation: Only about 5% (~300 mL in an adult) of the total blood volume is moving through capillaries at any given time due to the cyclical opening and closing of sphincters.

p.4
Capillary Structure and Function

Which type of capillary has tight junctions and is the most common type found in the body?
A) Discontinuous capillaries
B) Fenestrated capillaries
C) Continuous capillaries
D) Sinusoids
E) Arterioles

C) Continuous capillaries
Explanation: Continuous capillaries have well-developed occluding junctions between overlapping endothelial cells, providing continuity and regulating metabolic exchange. They are the most common type found in muscle, connective tissue, lungs, exocrine glands, and nervous tissue.

p.11
Lymphatic Vascular System

What distinguishes Purkinje fibers from contractile fibers?
A) They have a higher density of myofibrils
B) They contain more glycogen
C) They are located in the epicardium
D) They are smaller in diameter
E) They are found only in the atria

B) They contain more glycogen
Explanation: Purkinje fibers are distinguished by their greater diameter, abundant glycogen, and sparse bundles of myofibrils, which differentiate them from contractile fibers.

p.11
Lymphatic Vascular System

What is the function of lymphatic capillaries?
A) To transport oxygenated blood
B) To drain interstitial fluid as lymph
C) To supply blood to the heart
D) To regulate blood pressure
E) To connect arteries and veins

B) To drain interstitial fluid as lymph
Explanation: Lymphatic capillaries drain interstitial fluid that is not absorbed by venules, collecting it as lymph and playing a crucial role in fluid balance in the body.

p.7
Venous System Structure

How does the tunica adventitia of large veins compare to the tunica media?
A) It is thinner than the media
B) It is thicker than the media
C) It is absent in large veins
D) It is made entirely of smooth muscle
E) It contains no elastic fibers

B) It is thicker than the media
Explanation: In large veins, the tunica adventitia is thicker than the media and frequently contains longitudinal bundles of smooth muscle.

p.12
Capillary Structure and Function

Which description is true of continuous capillaries?
A) Unusually wide lumens
B) Most common in both brain and muscle
C) Abundant fenestrations
D) Lack a complete basement membrane
E) Phagocytic cells often seen inserted in the intercellular clefts

B) Most common in both brain and muscle
Explanation: Continuous capillaries are characterized by their continuous endothelial lining and are most commonly found in tissues such as the brain and muscle, where they facilitate selective permeability.

p.1
Arterioles and Blood Flow

What is the role of arterioles in thermoregulation?
A) They increase blood viscosity
B) They bypass capillary networks
C) They decrease blood flow to the heart
D) They regulate blood pressure directly
E) They increase oxygen delivery to tissues

B) They bypass capillary networks
Explanation: In thermoregulation, arterioles can bypass capillary networks and connect directly to venules, allowing for efficient regulation of blood flow and heat dissipation.

p.12
Venous System Structure

During light microscopic examination of a tissue, you note a vessel that has no smooth muscle but a large amount of connective tissue at its periphery. Which of the following vessels are you examining?
A) Arteriole
B) Venule
C) Elastic artery
D) Capillary
E) Large vein

B) Venule
Explanation: Venules typically lack smooth muscle and are surrounded by connective tissue, making them distinct from other types of vessels.

p.2
Microvascular Pathways

Which tissues are likely to have a high density of capillary beds?
A) Tissues with low metabolic rates
B) Tissues with high metabolic rates
C) Tissues that do not require oxygen
D) Tissues that are primarily connective
E) Tissues that are primarily epithelial

B) Tissues with high metabolic rates
Explanation: Tissues such as the kidney, liver, and muscles have a high density of capillary beds due to their increased metabolic activity, requiring more efficient nutrient and gas exchange.

p.3
Microvascular Pathways

In which system does one capillary bed drain into a vein that branches into another capillary bed?
A) Arteriovenous system
B) Venous portal system
C) Arterial portal system
D) Lymphatic system
E) Systemic circulation

B) Venous portal system
Explanation: The venous portal system allows for the drainage of one capillary bed into a vein, which then branches into another capillary bed, facilitating the rapid delivery of molecules to surrounding tissues.

p.3
Arterioles and Blood Flow

What is the primary structural feature of arterioles?
A) Thick muscular walls
B) Only endothelium in the intima
C) Multiple layers of smooth muscle
D) Large lumen diameter
E) Presence of valves

B) Only endothelium in the intima
Explanation: Arterioles are characterized by having an intima consisting only of endothelium, with one or two layers of smooth muscle in the media, making them distinct from larger arteries.

p.11
Lymphatic Vascular System

What are the three major layers of macroscopically visible blood vessels?
A) Endothelium, myocardium, adventitia
B) Intima, media, adventitia
C) Epicardium, intima, media
D) Tunica intima, tunica media, tunica externa
E) Endocardium, tunica media, adventitia

B) Intima, media, adventitia
Explanation: Macroscopically visible blood vessels are composed of three major layers: the intima, media, and adventitia, each serving specific functions in vascular structure and function.

p.11
Lymphatic Vascular System

What is the role of pericytes in the microvasculature?
A) To form the endothelial layer
B) To facilitate blood flow and assist in repair
C) To regulate blood pressure
D) To provide structural support to arteries
E) To initiate inflammation

B) To facilitate blood flow and assist in repair
Explanation: Pericytes surround the endothelium of capillaries and postcapillary venules, facilitating blood flow and playing a role in microvascular remodeling and repair.

p.12
Arterioles and Blood Flow

In a patient with type II diabetes, what vascular structures are most likely associated with the problems in blood distribution in the leg?
A) Veins and venules
B) Arterioles
C) Branches of the aorta
D) Lymphatic vessels
E) Ventricles

B) Arterioles
Explanation: The symptoms described, including cold and pale limbs, suggest issues with blood flow regulation, which is primarily controlled by arterioles.

p.5
Capillary Structure and Function

Where are fenestrated capillaries commonly found?
A) In the brain
B) In the liver
C) In the lungs
D) In endocrine organs and intestinal walls
E) In the skin

D) In endocrine organs and intestinal walls
Explanation: Fenestrated capillaries are typically located in organs where molecular exchange with the blood is important, such as endocrine organs and the walls of the intestines.

p.6
Venous System Structure

What happens at postcapillary venules during infection or tissue damage?
A) Blood pressure increases
B) White blood cells adhere to the endothelium and leave circulation
C) Red blood cells are produced
D) Nutrient absorption occurs
E) Blood flow is completely stopped

B) White blood cells adhere to the endothelium and leave circulation
Explanation: Postcapillary venules are the primary site where white blood cells adhere to the endothelium and exit the circulation to respond to infection or tissue damage.

p.11
Lymphatic Vascular System

What type of capillaries have many tight junctions?
A) Fenestrated capillaries
B) Discontinuous capillaries
C) Continuous capillaries
D) Sinusoids
E) Metarterioles

C) Continuous capillaries
Explanation: Continuous capillaries are characterized by many tight junctions, which restrict the exchange of substances to occur only through the endothelial cells.

p.5
Capillary Structure and Function

What is a key characteristic of sinusoidal capillaries?
A) They have a continuous basement membrane.
B) They have tight junctions between endothelial cells.
C) They have large fenestrations and a discontinuous basement membrane.
D) They are the most common type of capillary.
E) They are found only in the lungs.

C) They have large fenestrations and a discontinuous basement membrane.
Explanation: Sinusoids are characterized by their larger diameter, discontinuous basement membrane, and large fenestrations, allowing for the exchange of macromolecules and cells between tissue and blood.

p.11
Lymphatic Vascular System

What are the three major layers of the heart?
A) Endocardium, myocardium, epicardium
B) Epicardium, pericardium, myocardium
C) Myocardium, endothelium, adventitia
D) Epicardium, endothelium, tunica media
E) Myocardium, tunica intima, adventitia

A) Endocardium, myocardium, epicardium
Explanation: The heart consists of three major layers: the inner endocardium, the middle myocardium, and the outer epicardium, each with distinct structures and functions.

p.6
Venous System Structure

What is a characteristic feature of venules?
A) Thick walls and small lumens
B) Large diameter of the lumen compared to the thin wall
C) High pressure blood flow
D) Presence of valves only
E) No smooth muscle layers

B) Large diameter of the lumen compared to the thin wall
Explanation: Venules are characterized by a large lumen diameter relative to their thin walls, which allows for the efficient return of blood to the heart from the microvasculature.

Study Smarter, Not Harder
Study Smarter, Not Harder