Which statement does not accurately describe veins?
A)The 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)Always carry deoxygenated blood
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
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
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
Arterial blood pressure increases in response to:
A)increasing stroke volume
B)increasing heart rate
D)rising blood volume
E)all of these
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
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
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
The myocardium receives its blood supply directly from the:
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
Using the letters from column B, match the artery descriptions in column A. (some require more than a single choice)
(a)Right common carotid
(c)Left common carotid
(1) unpaired branch of abdominal aorta
(2) second branch of aortic arch
(3) branch of internal carotid
(4) branch of external carotid
(5) origin of femoral arteries
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 bracbial arteries, and through either the radial or ulnar artery to arrive at the hand. Which artery is missing from this sequence?
D)right common carotid
Which of the following do not drain directly into the inferior vena cava?
A)inferior phrenic veins
C)inferior mesenteric vein
Suppose that at a given point along a capillary, the following forces exist: capillary hydrostatic pressure (HPc) = 30 mmHg, interstitial fluid hydrostatic pressure (HPif) = 0 mmHg, capillary colloid osmotic pressure (OPc) = 25 mmHG, and interstitial fluid colloid osmotic pressure (OPic) = 2 mmHg. The net filtration pressure at this point in the capillary is:
How is the anatomy of capillary bed and capillaries suited to their functions?
Distinguish between elastic arteries, muscular arteries, and arterioles relative to location, histology, and functional adaptations
•Elastic arteries are the large, thick-walled arteries close to the heart. They have generous amounts of elastic tissue in all tunics, but especially in the tunica media. This elastic tissue enables them to withstand large pressure fluctuations by expanding when the heart contracts, forcing blood into them. They recoil as blood flows forward into the circulation during heart relaxation. They also contain substantial amounts of smooth muscle but are relatively inactive in vasoconstriction. (p. 695)
•Muscular arteries are medium-sized, and smaller arteries, farther along in the circulatory pathway, carry blood to specific body organs. Their tunica media contains proportionately more smooth muscle and less elastic tissue than that of elastic arteries, but they typically have an elastic membrane on each face of the tunica media. They are more active in vasoconstriction and are less distensible. (p. 696)
•Arterioles are the smallest of the arterial vessels. The smallest—terminal arterioles—feed directly into the capillary beds. The larger arterioles exhibit all three tunics and their tunica media is chiefly smooth muscle with a few scattered elastic fibers. The walls of the smaller arterioles are little more than smooth muscle cells that coil around the tunica intima lining. When arterioles constrict, the tissues served are largely bypassed; when the arterioles dilate, blood flow into the local capillaries increases dramatically. (p. 696)
Write an equation showing the relationship between peripheral resistance, blood flow, and blood pressure.
Define blood pressure.
Differentiate between systolic and diastolic pressures.
What is normal blood pressure for a young adult?
Blood pressure is the force per unit area exerted on the wall of a blood vessel by the blood contained within it. Systolic pressure is the pressure that occurs during systole when the aortic pressure reaches its peak. Diastolic pressure is the pressure that occurs during diastole when aortic pressure drops to its lowest level. (p. 703)
The normal blood pressure for a young adult is, on average, 120 mm Hg systolic and between 70 and 80 mm Hg diastolic. (p. 703)
Describe the neural mechanisms responsible for controlling blood pressure.
The neural controls responsible for controlling blood pressure operate via reflex arcs chiefly involving the following components: baroreceptors and the associated afferent fibers, the vasomotor center of the medulla, vasomotor (efferent) fibers, and vascular smooth muscle. The neural controls are directed primarily at maintaining adequate systemic blood pressure and altering blood distribution to achieve specific functions. (pp. 705–707)
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. (p. 712)
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
Describe neural and chemical (both systemic and local) effects exerted on the blood vessels when one is fleeing from a mugger?
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. (pp. 712–714)
How is nutrients, waste and respiratory gases transported to and from blood and tissue space?
(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. (p. 742)
Physiologists often consider capillaries and postcapillary venules together.
(a) What function 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.
Mrs. Johnson is brought to the emergency room after being involved in auto accident. She is hemorrhaging and has a rapid, thready pulse, but her blood pressure is within normal limits. Describe the compensatory mechanisms that are acting to maintain her blood pressure in the face of blood loss.
A 60-year-old man is unable to walk more than 100 yards without experiencing severe chest pain in his left leg; the pain is relieved by resting for 5-10. 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.
Your friend Joanie, who knows little about science, is reading a magazine article about a patient who had an aneurysm at the base of the brain that suddenly grew much larger. The surgeons' first goal was to “keep it from rupturing,” and the second goal was to “relieve 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. Joanie asks you what all this means. (Hint: Check chapter 19 Related clinical terms, p. 748).
An aneurysm is a balloonlike outpocketing of a blood vessel that places the vessel at risk for rupture. In this case, the aneurysm was so large that it was pressing on the brain stem and cranial nerves, threatening to interfere with the functions of these structures. The surgeons removed the ballooned section of the artery and sewed a section of strong tubing in its place. (p. 750)
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 degrees Farenheight/31 degrees Celsius) and the band uniforms are wool. Suddenly, Harry the tuba player becomes light-headed and faints. Explain his fainting in terms of vascular events.
Harry’s condition suggests that this is a case of transient vascular shock. Marching in the severe heat of the day caused the cutaneous blood vessels to dilate, which resulted in an increased blood volume pooling in the lower limbs (because of gravity). A subsequent decrease in blood flow to the heart caused Harry’s blood pressure to drop, and his dizziness and fainting was an indication that the brain was not receiving enough blood flow (hence, oxygen). (p. 711)
When one is 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 is picks up heat (by countercurrent exchange) from the nearby brachial artery en route. However, when one is 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.
Blood distribution is adjusted by a short-term neural control mechanism to meet specific demands. During exercise, the hypothalamus signals for reduced vasomotor stimulation of the skin vessels. Blood moves into the capillary beds, and heat radiates from the skin to reduce body temperature. (p. 716)
Finally you go to the oncology ward where Mrs. O'Leary is recovering from surgery for advanced breast cancer that had infiltrated her right breast and axillary lymph nodes. All of her axillary lymph nodes were removed and unfortunately, this severed most of the lymphatic vessels draining her right arm. You notice that her right arm is quite . Why?
Mrs. O'Leary is given a compression sleeve to wear on this arm to help relieve the edema.
Which of the pressures driving bulk flow at the capillaries will be altered by the compression sleeve?