Blood Vessels

When does blood flow through two consecutive capillary networks before returning to the heart?

In a portal system

____ is a point where two blood vessels merge

anastomosis

When does blood flow from an artery directly into a vein, bypassing the capillaries.

In an arteriovenous anastomosis (shunt)

Where do shunts naturally occur and why?

fingers, palms, toes and ears; to control heat loss

In an ____ two arteries merge and provide collateral routes of blood supply to a tissue.

arterial anastomosis

In a ____ two veins merge, providing several alternative routes of drainage from an organ.

venous anastomosis

The three layers of blood vessel walls from superficial to deep.

Tunica externa
Tunica media
Tunica intima(interna)

Which blood vessel layer merges with the connective tissue of neighboring blood vessels, nerves or other organs

Tunica externa

Which blood vessel layer anchors the vessel and provides passage for small nerves, lymphatic vessels, and smaller blood vessels

Tunica externa

Clotting of blood vessels

atherosclerosis

Hardening of blood vessels

arterosclerosis

Composition of the tunica externa

Loose connective tissue

What are the small vessels that supply blood to the outer half of the wall of larger blood vessels.

vasa vasorum

The thickest blood vessel layer

Tunica media

The blood vessel layer that consists of smooth muscle, collagen, and sometimes elastic tissue

Tunica media

The blood vessel responsible for vasoconstriction and vasodilation

Tunica media

Baroreceptors are located...
A) in the aorta and subclavian arteries.
B) in the aorta and carotid arteries.
C) aorta and carotid veins.
D) aorta and subclavian veins.
E) aorta and common iliac arteries.

b

Action potentials are conducted from the baroreceptors to the brain via...
A) the vagus nerve.
B) the vagus and glossopharyngeal nerves.
C) the vagus and phrenic nerves.
D) the phrenic and glossopharyngeal nerves.
E) the phrenic nerve.

b

The action potential from the brain to the heart travels along...
A) the vagus nerve.
B) the vagus and glossopharyngeal nerves.
C) the vagus and phrenic nerves.
D) the phrenic and glossopharyngeal nerves.
E) the phrenic nerve.

a

Heart rate and stroke volume decrease under decreased parasympathetic stimulation.
A) True
B) False

B

Increased sympathetic stimulation causes vasodilation, bringing elevated blood pressure back to normal.
A) True
B) False

b

Chemoreceptors in the carotid and aortic bodies detect all of the following except...
A) oxygen levels
B) blood pressure
C) pH
D) carbon dioxide
E) both A and D

b

Chemoreceptors are also located in the...
A) medulla oblongata.
B) pons.
C) hypothalamus.
D) thalamus.
E) spinal cord.

a

Which of the following will not increase the heart rate?
A) decreased blood oxygen
B) increased blood carbon dioxide
C) increased blood pressure
D) decreased blood pH

c

Increased sympathetic stimulation causes increased heart rate and stroke volume.
A) True
B) False

a

Chemoreceptors in the hypothalamus monitor blood carbon dioxide and pH.
A) True
B) False

b

The fluids leave the capillaries at the arterial end because...
A) the net filtration pressure of the blood is higher at the arterial end than it is at the venous end.
B) the net filtration pressure of the blood is higher at the venous end than it is at the arterial end.
C) the net filtration pressure of the interstitial fluid is higher at the arterial end than it is at the venous end.
D) the net filtration pressure of the interstitial fluid is higher at the venous end than it is at the arterial end.
E) the osmotic pressure is higher at the arterial end than it is at the venous end.

a

The fluids reenter the capillaries at the venous end because...
A) the net filtration pressure of the blood is higher at the arterial end than it is at the venous end.
B) the net filtration pressure of the blood is higher at the venous end than it is at the arterial end.
C) the net filtration pressure of the interstitial fluid is higher at the arterial end than it is at the venous end.
D) the net filtration pressure of the interstitial fluid is higher at the venous end than it is at the arterial end.
E) the osmotic pressure is higher at the venous end than it is at the arterial end.

d

Approximately what percent of fluid that exits the capillaries at the arterial end renters the capillaries at the venous end?
A) 60%
B) 70%
C) 80%
D) 90%
E) 100%

d

The lymphatic capillaries reabsorb as much as 20% of the fluid lost by the blood capillaries.
A) True
B) False

b

The net osmotic pressure is equal at both the arterial and the venous ends of the capillary.
A) True
B) False

a

Veins contain thick layers of smooth muscle and play a major role in regulating systemic blood pressure.
A) True
B) False

b

Circulatory shock can occur when output from the sympathetic nervous system is suddenly inhibited.
A) True
B) False

a

Diastolic pressure is the peak arterial BP reached during ventricular contraction, and systolic pressure is the minimum arterial BP between heartbeats.
A) True
B) False

b

What is the MABP in an individual with a blood pressure of 150/90?
A) 110
B) 120
C) 130
D) 150

a

The baroreceptors
A) transmit signals continually to the brainstem.
B) increase their signaling rate when the blood pressure rises.
C) excite the vagal nerves to the heart and dilate the arteries to lower BP.
D) all of the above

d

Reduced capillary reabsorption of fluid can lead to edema. Which of the following does not contribute to edema?
A) liver disease
B) dietary protein deficiency
C) extreme muscular activity
D) kidney diseases

c

Which of the following types of low venous return (LVR) shock occurs when released histamine causes extensive generalized vasodilation?
A) anaphylactic shock
B) septic shock
C) hypovolemic shock
D) neurogenic shock

a

Which of the following is not one of the three major branches arising from the aortic arch?
A) brachiocephalic trunk
B) left common carotid artery
C) left subclavian artery
D) right common carotid artery

d

In contrast to the superficial veins, the deep veins run parallel to the arteries and have similar names.
A) True
B) False

a

Blood vessels that connect two capillary networks are called:
A) portal systems
B) anastomoses
C) arterial systems
D) veins
E) capillary plexuses

a

The tissue layer of a vessel that differs most in thickness when comparing arteries and veins is the:
A) tunica externa
B) tunica adventitia
C) tunica media
D) tunica interna
E) tunica intima

c

These have the most control of perfusion of a capillary bed:
A) muscular arteries
B) precapillary sphincters
C) elastic arteries
D) sinusoids
E) fenestrated capillaries

b

These structures, present in medium-sized veins, prevent backflow of blood:
A) precapillary sphincters
B) venous tunica
C) skeletal muscles
D) fenestrations
E) venous valves

e

All of these factors may increase peripheral resistance except:
A) blood viscosity
B) length of vessel
C) radius of vessel
D) blood type
E) polycythemia

d

Venous pooling in a soldier standing at attention for a prolonged time occurs mainly when this mechanism fails:
A) cardiac suction
B) respiratory pump
C) skeletal muscle pump
D) gravity
E) pressure gradient

c

Venous anastomoses are more common than arterial anastomoses.
A) True
B) False

a

The smooth muscle in the walls of blood vessels is found in which of the following layers?
A) tunica adventitia
B) tunica media
C) tunica intima
D) all of the above

b

There is not enough blood in the body to fill the entire vascular system at once. About how much of the body's capillaries is closed at any given time?
A) 1/4
B) 1/3
C) 1/2
D) 3/4

d

Veins have lower blood pressure than arteries, averaging about 80mm Hg, in contrast to the 120mm Hg seen in large arteries during systole.
A) True
B) False

a

Arteries:
A) typically have a thicker tunica media than veins
B) contain a lower blood pressure than veins
C) may contain one-way valves
D) depend upon the massaging action of the skeletal muscles for a continuous flow of blood

a

Hypertension is a chronic resting blood pressure higher than which of the following?
A) 140/70
B) 120/80
C) 130/70
D) 140/90

d

Because of their ability to expand during systole and recoil during diastole, the elastic arteries "smooth out" changes in blood pressure.
A) True
B) False

a

A three-fold increase in the radius of a blood vessel produces an 81-fold increase in blood flow.
A) True
B) False

a

Accumulation of lactic acid in an active skeletal muscle promotes vasodilation to that muscle.
A) True
B) False

a

The most important mechanism of exchange between blood and tissue fluid is:
A) transcytosis
B) diffusion
C) filtration
D) active transport

b

The venous return of blood back to the heart is encouraged by
A) constriction of veins in the legs
B) a drop in internal pressure in the abdomen during inhalation
C) relaxation of skeletal muscle
D) gravity acting on the large veins above the heart

d

Both systemic and pulmonary arteries dilate in response to local hypoxia.
A) True
B) False

b

Vasodilation may be brought about by:
A) histamine
B) high blood oxygen
C) high blood carbon dioxide
D) angiotensin II

a

At the arterial end of a capillary:
A) net filtration pressure exceeds net reabsorption pressure
B) net filtration pressure is less than net reabsorption pressure
C) blood pressure is less than osmotic pressure
D) blood pressure is equal to osmotic pressure

a

Which of the following types of blood vessels has a thick tunica media, one-way valves, and carry blood back toward the heart?
A) arterioles
B) venules
C) elastic arteries
D) medium size veins

d

Blood flows from venules to:
A) capillaries
B) arterioles
C) medium sized veins
D) the heart

c

Which of these vessels has the largest lumen?
A) large artery
B) medium sized artery
C) venous sinus
D) large vein

d

Most medium-sized arteries are named for the organ or tissue they feed.
A) True
B) False

a

The outermost layer of all blood vessels is the:
A) tunica externa
B) tunica media
C) tunica intima

a

When net filtration pressure is greater than net reabsorption pressure more fluid enters the capillary than leaves it.
A) True
B) False

b

When a precapillary sphincter is closed, blood bypasses that capillary bed and travels directly from a _______ through a _______ to a venule.
A) arteriole, capillary
B) arteriole, thoroughfare channel
C) distributing artery, capillary bed

b

The vessels that supply the largest blood vessels with nutrients and remove waste are called:
A) tunica endothelium
B) metarteriole
C) vasa vasorum
D) portal system

c

The connective tissue of this vessel layer anchors the vessel and provides passage for lymphatic vessels:
A) tunica adventitia
B) tunica intima
C) tunica media
D) endothelium

a

As the diameter of a blood vessel increases, the resistance of blood flow:
A) decreases
B) increases
C) remains the same

a

Which type of capillary is the most "leaky"?
A) continuous capillaries
B) fenestrated capillaries
C) thoroughfare capillaries
D) sinusoids

b

Blood flows faster through the superior vena cava when you inhale.
A) True
B) False

b

Which statement does not accurately describe veins? (a) They have less elastic tissue and smooth muscle than arteries, (b) they contain more fibrous tissue than arteries, (c) most veins in the extremities have valves, (d) they always carry deoxygenated blood.

d

Smooth muscle in the blood vessel wall (a) is found primarily in the tunica intima, (b) is mostly circularly arranged, (c) is most abundant in veins, (d) is usually innervated by the parasympathetic nervous system.

b

Peripheral resistance (a) is inversely proportional to the length of the vascular bed, (b) increases in anemia, (c) is decreased in obesity, (d) is inversely related to the diameter of the arterioles.

d

Which of the following can lead to decreased venous return of blood to the heart? (a) an increase in blood volume, (b) an increase in venous pressure, (c) damage to the venous valves, (d) increased muscular activity.

c

Arterial blood pressure increases in response to (a) increasing stroke volume, (b) increasing heart rate, (c) arteriosclerosis, (d) rising blood volume, (e) all of these.

e

Which of the following would not result in the dilation of the feeder arterioles and opening of the precapillary sphincters in systemic capillary beds? (a) a decrease in local tissue O2 content, (b) an increase in local tissue CO2, (c) a local increase in histamine, (d) a local increase in pH.

d

The structure of a capillary wall differs from that of a vein or an artery because (a) it has two tunics instead of three, (b) there is less smooth muscle, (c) it has a single tunic—only the tunica intima, (d) none of these.

c

The baroreceptors in the carotid sinus and aortic arch are sensitive to (a) a decrease in CO2, (b) changes in arterial pressure, (c) a decrease in O2, (d) all of these.

b

The myocardium receives its blood supply directly from (a) the aorta, (b) the coronary arteries, (c) the coronary sinus, (d) the pulmonary arteries.

b

Blood flow in the capillaries is steady despite the rhythmic pumping of the heart because of the (a) elasticity of the large arteries, (b) small diameter of capillaries, (c) thin walls of the veins, (d) venous valves.

a

In atherosclerosis, which layer of the vessel wall thickens most? (a) tunica media, (b) tunica intima, (c) tunica adventitia, (d) tunica externa.

b

Suppose that at a given point along a capillary, the following forces exist: capillary hydrostatic pressure (HPc) = 30 mm Hg, interstitial fluid hydrostatic pressure (HPif) = 0 mm Hg, capillary colloid osmotic pressure (OPc) = 25 mm Hg and interstitial fluid colloid osmotic pressure (OPif) = 2 mm Hg. The net filtration pressure at this point in the capillary is (a) 3 mm Hg, (b) –3 mm Hg, (c) –7 mm Hg, (d) 7 mm Hg.

d