Test Your Knowledge ofTerms and Facts
1. Which of these statements is false? 2.
a. Most of the total blood volume is contained in veins.
b. Capillaries have a greater total surface area than any other type of vessel.
All arteries in the body contain oxygen-rich blood with the exception of a. the aorta. 4.
b. the pulmonary artery.
c. the renal artery.
d. the coronary arteries.
The "lub," or first heart sound, is produced by closing of 5.
a. the aortic semilunar valve.
b. the pulmonary semilunar valve.
c. the tricuspid valve.
d. the bicuspid valve.
e. both AV valves.
The first heart sound is produced at a. the beginning of systole.
b. the end of systole.
c. the beginning of diastole.
d. the end of diastole.
Changes in the cardiac rate primarily reflect changes in the duration of a. systole.
404 Chapter Thirteen
6. The QRS wave of an ECG is produced by a. depolarization of the atria.
b. repolarization of the atria.
c. depolarization of the ventricles.
d. repolarization of the ventricles.
7. The second heart sound immediately follows the occurrence of a. the P wave.
8. The cells that normally have the fastest rate of spontaneous diastolic depolarization are located in a. the SA node.
c. the bundle of His.
d. the Purkinje fibers.
9. Which of these statements is true?
a. The heart can produce a graded contraction.
b. The heart can produce a sustained contraction.
10. An ischemic injury to the heart that destroys myocardial cells is a. angina pectoris.
activation of factor X occurs in
the intrinsic pathway only.
the extrinsic pathway only.
both the intrinsic and extrinsic
neither the intrinsic nor extrinsic
12. Platelets a. form a plug by sticking to each other.
b. release chemicals that stimulate vasoconstriction.
c. provide phospholipids needed for the intrinsic pathway.
d. serve all of these functions.
e. any of these types.
14. Production of which of the following blood cells is stimulated by a hormone secreted by the kidneys?
15. Which of these statements about plasmin is true?
a. It is involved in the intrinsic clotting system.
b. It is involved in the extrinsic clotting system.
c. It functions in fibrinolysis.
d. It promotes the formation of emboli.
16. During the phase of isovolumetric relaxation of the ventricles, the pressure in the ventricles is a. rising.
c. first rising, then falling.
17. Peristaltic waves of contraction move fluid within which of these vessels?
a. arteries b. veins c. capillaries d. lymphatic vessels e. all of these
18. Excessive diarrhea may cause a. respiratory acidosis.
b. respiratory alkalosis.
c. metabolic acidosis.
d. metabolic alkalosis.
Test Your Understanding of Concepts and
Explain why the beat of the heart is automatic and why the SA node functions as the normal pacemaker.1 Compare the duration of the heart's contraction with the myocardial action potential and refractory period. Explain the significance of these relationships.
Describe the pressure changes that occur during the cardiac cycle and relate these changes to the occurrence of the heart sounds.
Can a defective valve be detected by an ECG? Can a partially damaged AV node be detected by auscultation (listening) with a stethoscope? Explain.
Describe the causes of the P, QRS, and T waves of an ECG and indicate at which point in the cardiac cycle each of these waves occurs. Explain why the first heart sound occurs immediately after the QRS wave and why the second sound occurs at the time of the T wave. Explain how a cut in the skin initiates both the intrinsic and extrinsic clotting pathways. Which pathway is shorter? Why?
Distinguish between the respiratory and metabolic components of acid-base balance. What are some of the causes of acid-base disturbances?
9. Explain how blood moves through arteries, capillaries, and veins. How does exercise affect this movement?
10. Explain the processes involved in the development of atherosclerosis. How might antioxidants help to retard the progression of this disease? How might exercise help? What other changes in lifestyle might help to prevent or reduce atherosclerotic plaques?
1 Note: This question is answered in the Chapter 13 Study Guide found on the Online Learning Center at www.mhhe.com/fox8.
TestYour Ability to Analyze and Apply Your Knowledge
1. Hematopoietic stem cells account for less than 1% of the cells in the bone marrow. These cells can be separated from the others prior to bone marrow transplantation, but it is better to first inject the donor with recombinant cytokines. Identify the cytokines that might be used and describe their effects.
2. A patient has a low red blood cell count, and microscopic examination of his blood reveals an abnormally high proportion of circulating reticulocytes. Upon subsequent examination, the patient is diagnosed with a bleeding ulcer. This is surgically corrected, and in due course his blood measurements return to normal. What was the reason for the low red blood cell count and high proportion of reticulocytes? A chemical called EDTA, like citrate, binds to (or "chelates") Ca2+. Suppose a person had EDTA infused into the blood. What effect would this have on the intrinsic and extrinsic clotting pathways? How would these effects differ from the effects of aspirin on blood clotting?
During the course of a physiology laboratory, a student finds that her PR interval is 0.24 second. Concerned, she takes her own ECG again an hour later and sees an area of the ECG strip where the PR interval becomes longer and longer. Performing an ECG measurement on herself for a third time, she sees an area of the strip where a P wave is not followed by a QRS or T; further along in the strip, however, a normal pattern reappears. What do you think these recordings indicate?
5. A newborn baby with a patent foramen ovale or a ventricular septal defect might be cyanotic (blue). Will a two-year-old with these defects also be cyanotic? Explain your answer.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.