CH 19 Blood vessels MAP questions

The outermost layer of a blood vessel is the tunica intima. True False

false ; the tunica externa is the outermost layer

Which arteries carry deoxygenated blood? renal arteries carotid arteries pulmonary arteries aorta

pulmonary arteries rationale: The pulmonary arteries carry deoxygenated blood from the right ventricle via the pulmonary trunk to the lungs for oxygenation.

Which vessel leaves the right ventricle of the heart to take oxygen-poor, dark red blood into pulmonary circulation? pulmonary vein superior vena cava pulmonary trunk aorta

pulmonary trunk

Which of the following is characteristic of veins but not arteries? large muscular tunic vasa vasorum larger internal diameter elastic membranes

larger internal diameter rationale: Veins have larger internal diameters than similar sized arteries.

Which of the following is NOT an important source of resistance to blood flow? vessel diameter blood viscosity vessel length total blood volume

total blood volume rationale: Total blood volume is not an important source of resistance to blood flow. However, blood volume does have a direct effect on blood pressure.

Which of the following is NOT an important source of resistance to blood flow? vessel diameter total blood volume vessel length blood viscosity

total blood volume rationale: Total blood volume is not an important source of resistance to blood flow. However, blood volume does have a direct effect on blood pressure.

A precapillary sphincter is a cuff of smooth muscle that regulates the flow of blood into the capillaries. True False

true

A sustained blood pressure of 140/90 or greater indicates hypertension in the patient. True False

true

An increase in blood viscosity will cause an increase in peripheral resistance. True False

true

Vasodilation will result in increased blood flow to a given tissue. True False

true

Explain how blood pressure is measured

- Measured indirectly by the auscultatory method using a sphygmomanometer - Pressure increased in cuff until it exceeds systolic pressure in brachial artery - Pressure released slowly and examiner listens for sounds of Korotkoff with a stethoscope

Describe the three wall layers found in arteries and veins

- Tunica intima (inner coat) • Endothelium • Subendothelial layer • Internal elastic membrane - Tunica media (middle coat) • (smooth muscle and elastic fibers) • External elastic membrane - Tunica externa (collagen fibers) • Vasa vasorum

Describe the three types of capillaries and where they are found

1. Continuous capillaries - Least permeable, and most common (e.g., skin, muscle). 2. Fenestrated capillaries - Large fenestrations (pores) increase permeability. Occurs in areas of active absorption or filtration (e.g., kidney, small intestine). 3. Sinusoid capillaries (sinusoids) - Most permeable. Occurs in special locations (e.g., liver, bone marrow, spleen).

Describe the factors that aid the return of blood to the heart through venous system

1. Muscular pump: contraction of skeletal muscles "milks" blood toward heart; valves prevent backflow 2. Respiratory pump: pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand 3. Venoconstriction under sympathetic control pushes blood toward heart

Predict the change in peripheral resistance as blood vessel diameter increases. A. Peripheral resistance decreases. B. Peripheral resistance increases. C. Peripheral resistance remains unchanged. D. Peripheral resistance is constant in humans.

A. Peripheral resistance decreases.

If you have a blood pressure of 120/80 mm Hg, what is your diastolic pressure? A. 40 mm Hg B. 80mmHg C. 120 mm Hg D. 200 mm Hg

B. 80mmHg

Which of the following blood vessel types have the greatest effect on peripheral resistance? A. Arteries B. Arterioles C. Veins D. Venules

B. Arterioles

Why is it important that blood pressure drop to lower levels as it reaches the capillary beds? Because capillaries are fragile and extremely permeable. Because capillaries actually need a higher blood pressure for filtration activities. Because capillaries actually are high-pressure vessels. Because capillaries depend on the lower pressure to prevent fluid exchange between the capillaries and the tissue fluid.

Because capillaries are fragile and extremely permeable. rationale: Low capillary pressures are desirable because capillaries are fragile and high pressures would rupture them. Most capillaries are extremely permeable and thus even the low pressure forces solute-containing fluids out of the bloodstream into the interstitial space.

How and under what conditions, blood flow is regulated through capillary beds

Blood flow through the capillary beds is regulated depending on the body's needs and is directed by nerve and hormone signals. e.g. after a large meal, most of the blood is diverted to the stomach by vasodilation (widening) of vessels of the digestive system and vasoconstriction (narrowing) of other vessels. e.g. During exercise, blood is diverted to the skeletal muscles through vasodilation, while blood to the digestive system would be lessened through vasoconstriction. The blood entering some capillary beds is controlled by small muscles called precapillary sphincters .

Of the following vessel types, which are responsible for the exchange of gases and nutrients with tissues? A. Arteries B. Arterioles C. Capillaries D. Veins

C. Capillaries

Why is vasodilation prominent in the skin when a person increases physical activity? A. It increases delivery of nutrients to the skin to induce sweating. B. Because skeletal muscles are close to the skin, they receive the oxygen via diffusion. C. Heat is dissipated across the skin from the blood to help cool the body. D. Exercise produces metabolites that induce vasodilation.

C. Heat is dissipated across the skin from the blood to help cool the body.

Why is low capillary pressure desirable?

Low capillary pressures are desirable because capillaries are fragile and high pressures would rupture them. Most capillaries are extremely permeable and thus even the low pressure forces solute-containing fluids out of the bloodstream into the interstitial space.

Which of the following is true about veins? Veins have a smaller diameter lumen than arteries. Veins are more muscular than arteries. Veins have valves; arteries do not. Veins carry blood away from the heart, while arteries carry blood to the heart.

Veins have valves; arteries do not. rationale: Veins have valves; arteries do not. Veins have valves to prevent the backflow of blood.

Which vessels carry blood away from the heart? capillaries venules arteries veins

arteries

What blood vessel experiences the steepest drop in blood pressure? venules arteries arterioles capillaries

arterioles

The aorta carries blood __________ the __________ of the heart. away from; right ventricle toward; left ventricle toward; right ventricle away from; left ventricle

away from; left ventricle rationale: What direction do arteries always carry blood? Is the aorta part of the pulmonary or systemic circuit?

How does blood pressure change throughout systemic circulation?

blood pressure decreases as the circulating blood moves away from the heart through arteries and capillaries into venules and veins.

Gas and nutrient exchanges between the blood and tissues take place at the __________. veins capillaries arterioles arteries

capillaries rationale: Capillaries are the sites for nutrient and gas exchanges between the blood and the interstitial fluid around tissues.

Large diameter, thick-walled arteries that are close to the heart and act as pressure reservoirs would be __________. arterioles muscular arteries veins elastic arteries

elastic arteries rationale: Elastic arteries are thick-walled arteries near the heart. These arteries are the largest in diameter. Elastic arteries act as pressure reservoirs; they expand and contract as blood is ejected from the heart.

Which type of vessel contains elastin in all three tunics to allow the vessel to expand and recoil as the heart ejects blood? elastic artery muscular artery distributing artery arteriole

elastic artery

The aorta is an example of a(n) __________. arteriole elastic artery muscular artery vein

elastic artery rationale: Elastic arteries are thick-walled arteries near the heart. These arteries are the largest in diameter. Elastic arteries act as pressure reservoirs; they expand and contract as blood is ejected from the heart.

All capillary beds are continuously perfused with blood. True False

false

The kidneys filter the blood; it is necessary for plasma, both fluid and dissolved chemicals, to be rapidly removed from the blood without the removal of larger proteins or cells. Which capillary would be best suited for this filtration? fenestrated capillaries continuous capillaries sinusoids anastomoses

fenestrated capillaries rationale: Fenestrated capillaries are found wherever active capillary absorption or filtrate formation occurs.

Blood from the lower limbs drains into the __________ before returning to the heart. thoracic aorta abdominal aorta superior vena cava inferior vena cava

inferior vena cava rationale: The inferior vena cava returns blood from the lower limbs to the heart.

Which vessel(s) return(s) oxygenated blood to the left atrium of the heart to complete the pulmonary circuit? pulmonary vein inferior vena cava pulmonary trunk pulmonary arteries

pulmonary vein

Which vessel(s) of the pulmonary circuit transport(s) oxygen-rich blood? pulmonary trunk aorta pulmonary arteries pulmonary veins

pulmonary veins

The influence of blood vessel diameter on peripheral resistance is ________. significant because resistance is directly proportional to the blood vessel diameter the only factor that influences resistance significant because resistance is inversely proportional to the fourth power of the vessel radius insignificant because vessel diameter does not vary

significant because resistance is inversely proportional to the fourth power of the vessel radius

The most permeable capillaries, which contain fenestrations and large intercellular clefts, are __________. arterioles sinusoid capillaries continuous capillaries fenestrated capillaries

sinusoid capillaries rationale: Sinusoid capillaries are the most permeable type of capillary due to large intercellular clefts among their endothelial cells. These capillaries allow large molecules--even blood cells--to pass into the surrounding tissue. Sinusoid capillaries are found in the liver, bone marrow, spleen, and adrenal medulla.

Arteries always carry oxygenated blood away from the heart. True False

true rationale: Arteries always carry blood away from the heart. However, blood in the pulmonary circuit is the opposite of what we might expect. Blood carried away from the heart and to the lungs is deoxygenated.

What is the outermost layer of the blood vessel wall for an artery or vein? subendothelial layer tunica intima tunica externa tunica media

tunica externa

Which vessels carry blood toward the heart? capillaries muscular arteries arterioles veins

veins rationale: The components of the arterial system are elastic arteries, muscular arteries, and arterioles. All components of the arterial system carry blood away from the heart. Capillaries connect arteries and veins via arterioles and venules and are not considered as either carrying blood away from or towards the heart. The components of the venous system are venules and veins. All components of the venous system carry blood towards the heart.

Which of the following is true about veins? Veins carry blood away from the heart, while arteries carry blood to the heart. Veins are more muscular than arteries. Veins have a smaller diameter lumen than arteries. Veins have valves; arteries do not.

veins have valves; arteries do not rationale: Veins have valves; arteries do not. Veins have valves to prevent the backflow of blood.

Describe the relationship between blood flow, blood pressure, and resistance

• Blood flow (F) directly proportional to blood pressure gradient (Δ P) - If Δ P increases, blood flow speeds up • Blood flow inversely proportional to peripheral resistance (R) - If R increases, blood flow decreases: • R more important in influencing local blood flow because easily changed by altering blood vessel diameter

Explain the primary functions of capillaries

• In all tissues except for cartilage, epithelia, cornea and lens of eye • Provide direct access to almost every cell • Functions - To exchange of gases, nutrients, wastes, hormones, etc., between blood and interstitial fluid