a&p 2 ch 19 review questions
Suppose OPif rises dramatically—say because of a severe bacterial infection in the surrounding tissue. (a) Predict how fluid flow will change in this situation. (b) Now calculate the NFP at the venous end of the capillary in Focus Figure 19.1 if OPif increases to 10 mm Hg. (c) In which direction does fluid flow at the venous end of the capillary now—in or out?
(a) An increase in interstitial fluid osmotic pressure (OPif) would tend to pull more fluid out of capillaries (causing localized swelling, or edema). (b) An increase of OPif to 10 mm Hg would increase the outward pressure on both the arteriolar and venous ends of the capillary. The NFP at the venous end would become 1 mm Hg (27 mm Hg - 26 mm Hg). (c) Fluid would flow out of the venous end of the capillary rather than in.
Name the type of artery that matches each description: major role in dampening the pulsatile pressure of heart contractions; vasodilation or constriction determines blood flow to individual capillary beds; have the thickest tunica media relative to their lumen size.
-Elastic arteries play a major role in dampening the pulsatile pressure of heart contractions -Dilation or constriction of arterioles determines blood flow to individual capillary beds. -Muscular arteries have the thickest tunica media relative to their lumen size.
You have just learned that hypertension can be treated with a variety of different drugs including diuretics, beta-blockers, and calcium channel blockers. Using your knowledge of the autonomic nervous system (Chapter 14), smooth muscle (Chapter 9), and cardiac muscle (Chapter 18), explain how these drugs work to decrease blood pressure.
-diuretics would decreased blood volume which would decrease bp and cardiac output -beta blockers block adrenergic receptors -calcium increases contractility so blockers decreases heart rate and contractility
List three factors that determine resistance in a vessel. Which of these factors is physiologically most important?
-viscosity of blood -length of blood vessel -diameter of blood vessel (most important)
Hypertension is defined physiologically as a condition of sustained arterial pressure of __________ or higher.
140/90
Your friend Jillian, who knows little about science, is reading a magazine article about a patient who had an "aneurysm at the base of his brain that suddenly grew much larger." The surgeons' first goal was to "keep it from rupturing," and the second goal was to "relieve the pressure on the brain stem and cranial nerves." The surgeons were able to "replace the aneurysm with a section of plastic tubing," so the patient recovered. Jillian asks you what all this means. Explain. (Hint: Check this chapter's Related Clinical Terms, p. 759.)
An aneurysm is a thin weakened section of the wall of an artery or a vein that bulges outward, forming a balloon like sac. If the aneurysm enlarges and the blood vessel wall becomes so thin it will burst. If it bursts, the result is massive hemorrhage with shock, severe pain, stroke or death. During surgery the surgeon removed the weakened area of the blood vessel and replaced it with a graft of synthetic material.
In emergency, Mr. Herrera is in anaphylactic shock. His capillaries have become leaky, allowing plasma proteins that are normally kept inside the blood vessels to escape into the interstitial fluid. Which of the bulk flow pressures is altered in this case and in what direction is the change?
Anaphylactic shock causes edema because of low osmotic pressure in the body tissue and high osmotic pressure in the capillaries. It occurs because the high osmotic pressure prevents the blood from re-entering the capillaries, causing the edema.
Explain the reasons for the observed changes in blood flow velocity in the different regions of the circulation.
Changes in the velocity in different regions of the circulation reflect the cross-sectional area of the vascular tubes to be filled. Because the cross-sectional area is least in the aorta and greatest in the capillaries, the blood flow is fastest in the aorta and slowest in the capillaries.
A 60-year-old man is unable to walk more than 100 yards without experiencing severe pain in his left leg; the pain is relieved by resting for 5-10 minutes. He is told that the arteries of his leg are becoming occluded with fatty material and is advised to have the sympathetic nerves serving that body region severed. Explain how such surgery might help to relieve this man's problem.
Cutting the nerves will open up the blood flow to the arteries. Since the sympathetic nerves will be severed, it will result in reduced vasoconstriction and vasodilation will occur.
Finally, in oncology Mrs. O'Leary is recovering from breast cancer surgery. Her right breast and all of her axillary lymph nodes were removed. Unfortunately, this severed most of the lymphatic vessels draining her right arm. You notice that this arm is quite edematous. Why? Mrs. O'Leary is given a compression sleeve to wear on this arm to help relieve the edema. Which of the bulk flow pressures will be altered by the compression sleeve?
Fluid pools in her arm because her lymphatic vessels can no longer drain. A compression sleeve would increase the interstitual fluids hydrostatic pressure, decreasing the amount of fluid leaking from the capillaries into her right arm.
The hepatic portal system collects blood from the __________ and then routes it to the __________.
GI tract; liver
The Agawam High School band is playing some lively marches while the coaches are giving pep talks to their respective football squads. Although it is September, it is unseasonably hot (88°F/31°C) and the band uniforms are wool. Suddenly Ryan, the tuba player, becomes light-headed and faints. Explain his fainting in terms of vascular events.
Harry experienced transient vascular shock. Marching in the heat caused his cutaneous blood vessels to dilate, resulting in an increased blood volume in his legs. A decrease in blood flow causes a decrease in blood pressure. Dizziness and fainting are an indication that the brain was not receiving enough blood flow.
Suppose you are in a bicycle race. What happens to the smooth muscle in the arterioles supplying your leg muscles? What is the key mechanism in this case?
In a bicycle race, autoregulation by intrinsic metabolic controls causes arteriolar smooth muscle in your legs to relax, dilating the vessels and supplying more O2 and nutrients to the exercising muscles.
Your patient in right heart failure is experiencing peripheral edema. Which of the four pressures that drive bulk fluid flow at capillaries has been changed as a result of the heart failure and in which direction?
In heart failure, the heart is no longer able to pump blood adequately (see p. 700). As a result, blood backs up into the veins and capillary beds and the hydrostatic pressure in the capillaries increases, causing edema.
First you encounter Mrs. Taylor in the medical unit awaiting a liver transplant. What is the connection between liver failure and her edema?
Liver failure causes a low level of protein albumin in the blood. Albumin is the main blood protein that maintains blood volume. Blood and excess fluid can build up causing the swelling.
Next in the obstetric ward, Mrs. So is experiencing premature labor and has edema in her legs. Which bulk flow pressures might be altered here?
Mrs. So's expanded uterus is pressing against her kidneys and her bladder. The pressure could cause a reduced filtration rate and cause water retention. The expanded uterus could also be compressing the iliac veins which reduces blood flow returning to the heart.
How does the control of blood flow to the skin for the purpose of regulating body temperature differ from the control of nutrient blood flow to skin cells?
Nutrient blood flow to the skin is controlled by autoregulation in response to the need for oxygen, whereas blood flow for regulating body temperature is controlled by neural intervention, that is, the sympathetic nervous system.
How are nutrients, wastes, and respiratory gases transported to and from the blood and tissue spaces?
Nutrients, wastes, and respiratory gases are transported to and from the blood and tissue spaces by diffusion
Name the arterial anastomosis at the base of the cerebrum.
The cerebral arterial circle (circle of Willis) is the arterial anastomosis at the base of the cerebrum.
Name the four unpaired arteries that emerge from the abdominal aorta.
The four unpaired arteries that emerge from the abdominal aorta are the celiac trunk, the superior and inferior mesenteric arteries, and the median sacral artery.
Which veins drain the dural venous sinuses and where do these veins terminate?
The internal jugular veins drain the dural venous sinuses. Each internal jugular vein joins a subclavian vein to form a brachiocephalic vein.
Name the leg veins that often become varicosed.
The leg veins that often become varicosed are the great and small saphenous veins.
At a given point in a capillary, suppose that capillary hydrostatic pressure is 32 mm Hg, interstitial fluid hydrostatic pressure is 1 mm Hg, capillary colloid osmotic pressure is 25 mm Hg, and interstitial fluid osmotic pressure is 2 mm Hg. Draw a line representing the capillary wall and label the compartments on either side as "capillary lumen" and "interstitial fluid." For each of the four pressures, draw an arrow across the capillary wall pointing in the correct direction, and label it with the appropriate name and value. Calculate the net filtration pressure. Would you expect to find this point at the venous or arterial end of the capillary?
The net filtration pressure (NFP) at this point in the capillary is 8 mm Hg (34 mm Hg - 26 mm Hg). This is a net outward pressure, which tells us that this point in the capillary is near the arterial end of the capillary.
In what important way does the area drained by the vertebral veins differ from the area served by the vertebral arteries?
The vertebral arteries help supply the brain, but the vertebral veins do not drain much blood from the brain.
Describe neural and chemical (both systemic and local) effects exerted on the blood vessels when you are fleeing from a mugger. (Be careful, this is more involved than it appears at first glance.)
When one is fleeing from a mugger, blood flow is diverted to skeletal muscles from other body systems not in direct need of large volumes of blood. Blood flow increases in response to acetylcholine release by sympathetic vasodilator fibers and/or epinephrine binding to beta receptors of vascular smooth muscles in the skeletal muscles, and virtually all capillaries open to accommodate the increased flow. Systemic adjustments, mediated by the sympathetic vasomotor center, occur to ensure that increased blood volume reaches the muscles. Strong vasoconstriction of the digestive viscera diverts blood away from those regions temporarily, ensuring that an increased blood supply reaches the muscles. Bloodborne epinephrine enhances blood glucose levels, alertness, and metabolic rate. The major factor determining how long muscles can continue vigorous activity is the ability of the cardiovascular system to deliver adequate oxygen and nutrients.
You are assessing the circulation in the leg of a diabetic patient at the clinic. Name the artery you palpate in each of these three locations: behind the knee, behind the medial malleolus of the tibia, on the dorsum of the foot.
You would palpate the popliteal artery behind the knee, the posterior tibial artery behind the medial malleolus of the tibia, and the dorsalis pedis artery on the foot.
Which of the following would not result in the dilation of the terminal arterioles and upstream arterioles 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.
a local increase in pH
Use Figure 19.7 on p. 716 to answer the following questions: (a) In which type of vessel is the largest pressure drop? (b) Which type of vessel is the first in which there is no difference in pressure between systole and diastole? Why is this a good thing? (c) How much pressure remains at the start of the venules to get blood back to the heart? What else helps blood return to the heart?
a. arterioles b. capillaries c. About 15-17 mm Hg is left at the start of the venules to get blood back to the heart. Factors that help blood return to the heart include venous valves, the muscular pump, the respiratory pump, and sympathetic venoconstriction.
Physiologists often consider capillaries and postcapillary venules together. (a) What functions do these vessels share? (b) Structurally, how do they differ?
a.) The text states that postcapillary venules function "more like capillaries" (p. 698), meaning that exchanges of small molecules between the blood and the surrounding tissue fluid occur across these venules. Furthermore, inflammatory fluid and leukocytes leave the postcapillary venules just as they exit the capillaries.b). Whereas capillaries consist only of an endothelium, postcapillary venules have scattered fibroblasts on their endothelium layer.
(a) What blood vessels contribute to the formation of the hepatic portal circulation? (b) Why is a portal circulation a "strange" circulation?
a.) The veins draining the digestive viscera contribute to the formation of the hepatic portal circulation. The most important of these are the superior and inferior mesenteric veins and the splenic veins.b.) The portal circulation is a "strange" circulation because it consists of veins draining into capillaries, which drain into veins again.
Arterial blood pressure increases in response to (a) increasing stroke volume, (b) increasing heart rate, (c) atherosclerosis, (d) rising blood volume, (e) all of these.
all of these
Which of the following acts on the kidneys and blood vessels to raise blood pressure?
antidiuretic hormone
Blood services the myocardium of the heart by coronary vessels that originate from the __________.
aorta
Blood flows directly from __________ into capillary beds.
arterioles
(a) Define blood pressure. Differentiate between systolic and diastolic blood pressure. (b) What is the normal blood pressure value for an adult?
blood pressure- force exerted by blood against a unit area of the blood vessel walls systolic pressure- pressure exerted by blood on the blood vessels walls during ventricular contractions diastolic pressure- arterial blood pressure reaches during as a result of diastole; lowest level of any given cardiac cycle b) normal blood pressure is 120/80
Changes in peripheral resistance are primarily driven by __________.
blood vessel diameter
Your neighbor, Bob, calls you because he thinks he is having an allergic reaction to a medication. You find Bob on the verge of losing consciousness and having trouble breathing. When paramedics arrive, they note his blood pressure is 63/38 and he has a rapid, thready pulse. Explain Bob's low blood pressure and rapid heart rate.
bob is in anaphylactic shock. this results in vasodilation and a huge drop in resistance which results in low bp. this low bp triggers baroreceptors which speed up the heart by activating the sympathetic nervous system
Tracing the blood from the heart to the right hand, we find that blood leaves the heart and passes through the aorta, the right subclavian artery, the axillary and brachial arteries, and through either the radial or ulnar artery to arrive at the hand. Which artery is missing from this sequence? (a) coronary, (b) brachiocephalic, (c) cephalic, (d) right common carotid.
brachiocephalic aortic arch> brachiocephalic> r. subclavian> r. axillary
The only vessels that provide direct access to nearly every cell in the body are the __________.
capillaries
Exchange of gases and nutrients occurs by diffusion between the __________.
capillaries and tissue cells
Which of the following abdominal arteries branches to form the common hepatic artery, left gastric artery, and splenic artery?
celiac trunk
The baroreceptors in the carotid sinus and aortic arch are sensitive to
changes in arterial pressure and stretch
Most neural controls of blood pressure involve input from baroreceptors, which are sensitive to __________.
changes in blood pressure
Any condition in which blood vessels are inadequately filled and blood CANNOT circulate normally is called __________.
circulatory shock
The vessels that exhibit the lowest level of permeability are the __________.
continuous capillaries
The myocardium receives its blood supply directly from the
coronary arteries
Which statement does not accurately describe veins? (a) have less elastic tissue and smooth muscle than arteries, (b) contain more fibrous tissue than arteries, (c) most veins in the extremities have valves, (d) always carry deoxygenated blood.
d
Total peripheral resistance (a) is inversely proportional to the length of the vascular bed, (b) increases in anemia, (c) decreases in polycythemia, (d) is inversely related to the diameter of the arterioles.
d) is inversely related to the diameter of the arterioles -if blood flow decreased TPR would increase so if diameter decreases TPR increases
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.
damage to the venous valves
The minute-to-minute blood flow through the capillary beds is determined by the __________.
diameter of arterioles
Distinguish between elastic arteries, muscular arteries, and arterioles relative to location, histology, and functional adaptations.
elastic arteries: conduct blood from the heart medium sized vessels muscular arteries: deliver blood to body organs; have the thickest tunica media; smooth muscle is active in vasoconstriction arterioles: control flow into capillary beds via vasodilation and vasoconstriction of smooth muscle
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.
elasticity of the large arteries
If many arterioles in your body dilated at once, you would expect MAP to plummet. What prevents MAP from decreasing during your bicycle race?
extrinsic mechanisms such as the sympathetic nervous system causes vasoconstriction in other areas. cardiac output would also increase which increases bp
Baroreceptors are effective in long-term regulation of blood pressure.
false
If the net filtration pressure (NFP) is positive, then fluid is reabsorbed into the blood.
false
Which of the following veins is the longest in the body?
great saphenous vein
what kind of control is angiotensin II
hormonal control of blood flow
At the arteriolar end of a capillary, __________ pushes fluid into the capillary.
hydrostatic pressure in the interstitial fluid
A metarteriole is a vessel that __________.
in intermediate between the arteriole and the capillary bed
Blood flow would be increased by __________.
increasing cardiac output
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.
it has a single tunic—only the tunica intima
The major long-term mechanism of blood pressure control is provided by the __________.
kidneys
Blood flows from the lungs to the __________ via the __________.
left atrium; pulmonary veins
During systemic circulation, blood leaves the __________.
left ventricles and flows directly into the aorta
__________ inhibits fibrinolysis by competing with plasminogen and may contribute to the formation of atherosclerotic plaques.
lipoprotein (a)
what kind of control is nitric oxide
metabolic control of blood flow
Cardiogenic shock is most likely to result from __________.
multiple heart attacks
An elastic lamina on both sides of the tunica media is a characteristic of __________.
muscular arteries
Which of the following types of blood vessels have the proportionally thickest tunica media of all vessels?
muscular arteries
what kind of control is stretch of vascular smooth muscle
myogenic control of blood flow
what kind of control is sympathetic impulses
nervous system control of blood flow
Fluids are likely to leave or filter out of the capillary if __________.
net hydrostatic pressure (HP) is greater than net osmotic pressure
The presence of __________ stabilizes the wall of capillaries.
pericytes
Which of the following regulates blood flow at the entrance to each true capillary?
precapillary sphincter
Which of the following conditions would increase the chances of developing varicose veins?
pregnancy, a potbelly in an obese person, standing to attention for long periods of time
The inferior vena cava brings blood from the lower regions of the body and empties into the __________.
right atrium
during pulmonary circulation, blood leaves the_____________.
right ventricle and flows directly to the lungs
The endothelium is composed of __________.
simple squamous epithelium
Which of the following would experience increased blood flow during exercise?
skin
Blood from the brain is returned to the heart via the __________.
superior vena cava
the flow of blood from the left ventricle to the right atrium is called the
systemic circulation
Which of the following blood vessels is the most susceptible to atherosclerosis?
the aorta
When we are cold or the external temperature is low, most venous blood returning from the distal part of the arm travels in the deep veins where it picks up heat (by countercurrent exchange) from the nearby brachial artery en route. However, when we are hot, and especially during exercise, venous return from the distal arm travels in the superficial veins and those veins tend to bulge superficially in a person who is working out. Explain why venous return takes a different route in the second situation.
the blood vessels dilate and go through the superficial veins to release some of the heat through the skin
Which paired artery supplies most of the tissues of the head except for the brain and orbits?
the external carotid arteries supply most of the tissues of the head except for the brain and orbitis
The kidneys play an important role in maintaining MAP by influencing which variable? Explain how renal artery obstruction could cause secondary hypertension.
the kidneys help maintain blood pressure by influencing blood volume. In renal artery obstruction, the blood pressure in the kidney is lower than in the rest of the body (because it is downstream from the obstruction). Low renal blood pressure triggers both direct and indirect renal mechanisms to increase blood pressure by increasing blood volume. This can cause hypertension (called "secondary hypertension" because it is secondary to a defined cause—in this case the renal artery obstruction).
Which of the following is the major force generating blood flow?
the pumping action of the heart
Suppose vasoconstriction decreases the diameter of a vessel to one-third its size. What happens to the rate of flow through that vessel? Calculate the expected size of the change.
the rate of slow is decreased 3^4 so 81
Which branch of the autonomic nervous system innervates blood vessels? Which layer of the blood vessel wall do these nerves innervate? What are the effectors (cells that carry out the response)?
the sympathetic nerve system innervates the blood vessels. the nerves innervate the tunica media. and the effectors are smooth muscle cells.
How is the anatomy of capillaries and capillary beds well suited to their function?
they are thin to allow the diffusion of nutrients/wastes across the membrane
Write an equation showing the relationship between total peripheral resistance, blood flow, and blood pressure.
total peripheral resistance= blood pressure/ blood flow
Which of the following is the correct sequence of layers in the vessel wall from superficial to deep?
tunica externa, tunica media, tunica intima
The vessel layer that has a direct role in vasoconstriction is the __________.
tunica media
Which of the layers of an artery wall is regulated by the sympathetic nervous system and many hormones?
tunica media
Loss of vasomotor tone that results in a huge drop in peripheral resistance is known as __________.
vascular shock
Reduction in the lumen diameter of a blood vessel as the smooth muscle contracts is known as __________.
vasoconstriction
Describe the neural mechanisms responsible for controlling blood pressure.
vasomotor center (brain area concerned with regulation of blood vessel resistance) vasomotor fibers (sympathetic nerve fibers that cause the contraction of smooth muscle in the walls of blood vessels) baroreceptors- (sensitive to vessel stretch and inhibit vasomotor and cardioacceleratory centers and stimulate cardioinhibitory center) chemoreceptors (stimulated by increased CO2 and decreased pH and then stimulates the cardioacceleratory center)
In the systemic circuit, which contains more blood—arteries or veins—or is it the same?
veins
Up to 65% of the body's blood supply is found in __________.
veins
Which have more anastomoses, arteries or veins?
veins
What is the function of venous valves? What forms the valves?
venous valves prevent blood from flowing backwards in veins. they are formed from folds of the tunica intima
When would the capillary beds surrounding the gastrointestinal organs be open?
when digesting a meal
When vascular smooth muscle contracts, what happens to the diameter of the blood vessel? What is this called?
when the muscle contract the diameter shrinks. this is called vasoconstriction
Describe the baroreceptor reflex changes that occur to maintain blood pressure when you rise from a lying-down to a standing position.
when you first stand up your blood pressure drops and this is sensed by aortic and carotid baroreceptors. sympathetic reflexes are increased. heart and rate contractility increase, increasing cardiac output and blood pressure. vasoconstriction by the sympathetic nervous system also increases blood pressure
