Question 1

Factors that aid venous return include all except ________.
A) venous valves
B) activity of skeletal muscles
C) pressure changes in the thorax
D) urinary output

Accepted Answer

Urinary output does not directly aid in venous return as it involves the removal of excess fluids and waste from the body through the kidneys and urinary system, rather than facilitating the movement of blood back to the heart through the veins. Venous valves, the activity of skeletal muscles, and pressure changes in the thorax all play important roles in promoting venous return by preventing backflow, compressing the veins, and creating pressure gradients, respectively.

Question 2

Which of the following is likely during vigorous exercise?
A) Blood flow to the kidneys increases.
B) Blood will be diverted to the digestive organs.
C) The skin will be cold and clammy.
D) Capillaries of the active muscles will be engorged with blood.

Accepted Answer

During vigorous exercise, the body diverts blood flow towards the active muscles to supply them with oxygen and nutrients. This causes the capillaries of the active muscles to become engorged with blood. Blood flow to the kidneys and digestive organs decreases during exercise as the body prioritizes blood flow to the muscles. The skin may become warmer due to increased blood flow, but it should not be cold and clammy. Therefore, the best choice is D.

Question 3

Which of the choices below does not explain why low capillary pressures are desirable?
A) Low blood pressure is associated with longer life span than high blood pressure.
B) Low capillary pressure reduces the load of drainage the lymphatic drainage must handle.
C) Capillaries are fragile and high pressures would rupture them.
D) Most capillaries are extremely permeable and thus even low pressures force solute-containing fluid out of the bloodstream.

Accepted Answer

Option A does not explain why low capillary pressures are desirable, as it talks about blood pressure in general and not specifically about capillary pressure. Options B, C, and D all provide reasons for why low capillary pressures are desirable.

Question 4

Which of the following is least involved in pulmonary circulation?
A) right ventricle
B) superior vena cava
C) pulmonary arteries and veins
D) left atrium

Accepted Answer

The superior vena cava brings deoxygenated blood from the upper part of the body to the right atrium, which is then pumped by the right ventricle to the pulmonary arteries and then to the lungs for oxygenation. The oxygenated blood returns to the heart via pulmonary veins and enters the left atrium, which pumps it to the left ventricle for distribution to the rest of the body. Therefore, all the other choices (A, C, and D) are involved in pulmonary circulation except for the superior vena cava (B).

Question 5

Brain blood flow autoregulation ________. A) is less sensitive to pH than to a decreased oxygen level B) is controlled by cardiac centers in the pons C) is abolished when abnormally high CO₂ levels persist D) causes constriction of cerebral blood vessels in response to a drop in systemic blood pressure

Accepted Answer

Brain blood flow autoregulation is sensitive to CO2 levels, and high CO2 levels can impair autoregulation, leading to vasodilation rather than constriction.

Question 6

Blood flow to the skin ________.
A) is not an important source of nutrients and oxygen for skin cells
B) is controlled mainly by decreasing pH
C) increases when environmental temperature rises
D) increases when body temperature drops so that the skin does not freeze

Accepted Answer

Blood flow to the skin increases when environmental temperature rises in order to dissipate heat and regulate body temperature.

Question 7

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

Accepted Answer

According to Poiseuille's law, resistance to blood flow is inversely proportional to the fourth power of the radius of the blood vessel. Therefore, changes in blood vessel diameter have a significant impact on peripheral resistance.

Question 8

Which of the following is the most significant source of blood flow resistance?
A) blood viscosity
B) blood vessel diameter
C) total blood vessel length
D) blood vessels type

Accepted Answer

Blood vessel diameter is the most significant source of blood flow resistance as it has the greatest influence on blood flow resistance according to the Poiseuille's law. Blood viscosity, total blood vessel length, and blood vessel type also contribute to blood flow resistance but to a lesser extent compared to blood vessel diameter.

Question 9

Which of the following processes provides a long-term response to changes in blood pressure?
A) chemoreceptor-initiated reflexes
B) neural controls
C) renal regulation
D) baroreceptor-initiated reflexes

Accepted Answer

Renal regulation is the process by which the kidneys adjust blood pressure in the long term through the renin-angiotensin-aldosterone system and the regulation of fluid and electrolyte balance. The other options provide short-term responses to changes in blood pressure but do not contribute to long-term regulation.

Question 10

The form of circulatory shock known as hypovolemic shock is ________.
A) shock that results from large-scale loss of blood volume, or after severe vomiting or diarrhea
B) always fatal
C) the form of shock caused by anaphylaxis
D) any condition in which blood vessels are inadequately filled and blood cannot circulate normally

Accepted Answer

Hypovolemic shock is a type of shock that occurs due to the large-scale loss of blood volume, severe vomiting, or diarrhea. It is not always fatal but can be if not treated promptly. Anaphylactic shock is a different type of shock caused by severe allergic reactions. The definition provided in option D is of shock in general and doesn't define hypovolemic shock specifically.

Question 11

Which of the choices below reflects the balance (or imbalance)between the direction and amount of fluid that flows across the capillary walls?
A) hydrostatic pressure only
B) hydrostatic and osmotic pressure
C) plasma and formed element concentration
D) blood volume and viscosity

Accepted Answer

The balance between the direction and amount of fluid that flows across the capillary walls is determined by the balance between hydrostatic pressure (which tends to push fluid out of the capillaries) and osmotic pressure (which tends to pull fluid back into the capillaries). Therefore, choice B, which includes both hydrostatic and osmotic pressure, best reflects this balance. Choices A, C, and D do not fully capture this balance.

Question 12

Due to the branching of arteries the type of arteries that would be most numerous would be ________.
A) arterioles
B) pulmonary arteries
C) muscular arteries
D) elastic arteries

Accepted Answer

Arterioles are the smallest branches of arteries and are responsible for controlling blood flow to capillary beds. Due to their small size, they are numerous throughout the body.

Question 13

These capillaries may be lined with phagocytes that can extend their process into the plasma to catch "prey."
A) fenestrations
B) anastomoses
C) thoroughfare channels
D) sinusoids

Accepted Answer

The description of capillaries lined with phagocytes that extend their process into the plasma to catch "prey" matches with sinusoids. Sinusoids have irregularly shaped lumens with gaps in the lining cells, allowing for the passage of large molecules like proteins and blood cells. They are commonly found in the liver, spleen, and bone marrow where they play a role in removing old or damaged cells from circulation.

Question 14

Which of the choices below explains why the arterioles are known as resistance vessels?
A) The contraction and relaxation of the smooth muscle in their walls can change their diameter.
B) They contain a large quantity of elastic tissue.
C) They distribute blood to various parts of the body.
D) Their prime function is the exchange of nutrients and wastes between the blood and tissue cells.

Accepted Answer

Arterioles are known as resistance vessels because the contraction and relaxation of the smooth muscle in their walls can change their diameter, which in turn affects the resistance to blood flow and the distribution of blood pressure.

Question 15

Which of the following is a type of circulatory shock?
A) vascular, due to extreme vasodilation as a result of loss of vasomotor tone
B) cardiogenic, which results from any defect in blood vessels
C) circulatory, where blood volume is normal and constant
D) hypovolemic, caused by increased blood volume

Accepted Answer

Vascular shock is a type of circulatory shock caused by extreme vasodilation and loss of vasomotor tone, leading to inadequate blood flow.

Question 16

Histologically,the ________ is squamous epithelium supported by a sparse connective tissue layer.
A) tunica externa
B) tunica adventitia
C) tunica intima
D) tunica media

Accepted Answer

The tunica intima is the innermost layer of blood vessels and is composed of a single layer of squamous epithelium called endothelium, supported by a sparse connective tissue layer.

Question 17

The term ductus venosus refers to ________.
A) damage to the valves in the veins, leading to varicose veins
B) a condition of the aged in which the arteries lose elasticity
C) a fetal shunt that bypasses the lungs
D) a special fetal vessel that allows umbilical blood to bypass the liver

Accepted Answer

The ductus venosus is a special fetal blood vessel that allows oxygenated blood from the placenta to bypass the liver and flow directly to the inferior vena cava, which then carries the blood to the heart. This is important because the fetus does not use its lungs for oxygen exchange while in utero, so the liver does not need to process as much blood. The ductus venosus closes shortly after birth when the baby starts using its lungs, and becomes a ligament.

Question 18

Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation?
A) tunica externa
B) tunica adventitia
C) tunica media
D) tunica intima

Accepted Answer

The tunica media is primarily responsible for maintaining blood pressure and continuous blood circulation as it contains smooth muscle cells that can contract and relax to regulate blood flow and vessel diameter. The tunica externa (also known as the adventitia) is the outer layer of the artery and provides support and protection, while the tunica intima is the inner layer in direct contact with the blood and helps to reduce friction and prevent clotting.

Question 19

The pulse rate depends on all of the following except one.Select the one answer the does not affect a pulse rate reading.
A) activity
B) the vessel selected to palpate
C) emotions
D) postural changes

Accepted Answer

The vessel selected to palpate can affect the ease of detecting a pulse, but it does not affect the actual pulse rate reading. The pulse rate is primarily influenced by activity, emotions, postural changes, and other physiological factors.

Question 20

Which of the following is not true regarding fenestrated capillaries?
A) Fenestrated capillaries in endocrine organs allow hormones rapid entry into the blood.
B) Fenestrated capillaries are essential for filtration of blood plasma in the kidney.
C) Fenestrated capillaries form the blood-brain barrier.
D) Fenestrated capillaries in the small intestine receive nutrients from digested food.

Accepted Answer

Fenestrated capillaries do not form the blood-brain barrier. This is done by tight junctions between endothelial cells in the CNS, which prevent diffusion of substances between the blood and brain tissue. Fenestrated capillaries do allow for rapid exchange of materials between the blood and tissues in other organs, including endocrine organs, the kidney, and the small intestine.

Quiz 19: The Cardiovascular System: Blood Vessels

Factors that aid venous return include all except ________.

Which of the following is likely during vigorous exercise?

Which of the choices below does not explain why low capillary pressures are desirable?

Which of the following is least involved in pulmonary circulation?

Brain blood flow autoregulation ________.

Blood flow to the skin ________.

The influence of blood vessel diameter on peripheral resistance is ________.

Which of the following is the most significant source of blood flow resistance?

Which of the following processes provides a long-term response to changes in blood pressure?

The form of circulatory shock known as hypovolemic shock is ________.

Which of the choices below reflects the balance (or imbalance) between the direction and amount of fluid that flows across the capillary walls?

Due to the branching of arteries the type of arteries that would be most numerous would be ________.

These capillaries may be lined with phagocytes that can extend their process into the plasma to catch "prey."

Which of the choices below explains why the arterioles are known as resistance vessels?

Which of the following is a type of circulatory shock?

Histologically,the ________ is squamous epithelium supported by a sparse connective tissue layer.

The term ductus venosus refers to ________.

Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation?

The pulse rate depends on all of the following except one.Select the one answer the does not affect a pulse rate reading.

Which of the following is not true regarding fenestrated capillaries?