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Quick Check and Active Learning
Answer Keys
CHAPTER 13
QUICK CHECK
Page 340
1. Plasma
2. 7% to 9%
3. Blood is slightly alkaline, with a pH between 7.35 and 7.45–always staying just above the chemically
neutral point of 7.00.
Page 342
Note: The following answers are for the first Quick Check exercise.
1. Plasma proteins (albumins and globulins)
2. Red blood cells, white blood cells, and platelets
3. Myeloid tissue and lymphatic tissue
Note: The following answers are for the second Quick Check exercise.
1. In the aspiration biopsy cytology (ABC) procedure, a sample of myeloid tissue is drawn into a syringe
from inside the pelvic bone or sternum. It allows for the examination of tissue, which may help to
confirm or reject a tentative diagnosis. In a bone marrow transplant, myeloid tissue from a compatible
donor is introduced into the recipient intravenously. If the recipient’s immune system does not reject
the new tissue, a new colony of healthy tissue may become established in the bone marrow.
2. Hematopoietic or stem cells
Page 343
1. The biconcave disk shape provides a large surface area for moving dissolved gases (oxygen and
carbon dioxide) and other solutes quickly in or out of the blood cell.
2. The CBC or complete blood cell count is a battery of tests used to measure the amounts or levels of
many blood constituents. It is often ordered as a routine part of the physical examination.
3. The hematocrit test gives an example of the proportion of RBCs to plasma. Such information could
help screen for dehydration, hemorrhaging, or other circumstances that affect the RBC ratio.
Page 348
1. Blood type O is the universal donor. Blood type AB is the universal recipient.
2. RhoGam stops the mother’s body from forming anti-Rh antibodies and thus prevents the possibility of
harm to the next Rh positive baby.
Page 351
1. Polycythemia is characterized by dramatic increases in RBC numbers. In contrast, anemia results
from inadequate numbers of RBCs, a deficiency in the production of normal hemoglobin, or
production of hemoglobin that is in some way defective.
2. Anemic individuals often feel fatigued or “tired all the time” and suffer from weakness, skin pallor,
headache, and faintness. Other symptoms include increased heart and respiratory rates.
3. The types of anemia include the following.
•
•
•
Hemorrhagic anemia: loss of RBCs (extensive surgery or sudden trauma)
Deficiency anemia: inadequate supply of some substance, such as vitamin B 12 or iron and
chemical changes in hemoglobin, resulting in defective hemoglobin
Hemolytic anemia: decreased RBCs due to increased rate of destruction of RBCs (abnormal
hemoglobin).
Page 1 of 12
Quick Check and Active Learning
Answer Keys
4. Hemolytic disease of the newborn begins during pregnancy if fetal RBCs of a different ABO type or
Rh factor than the mother cross the placenta and enter the mother’s circulation. This can happen
during delivery as blood cells leak from the placenta as it pulls away from the lining of the uterus. If
this should occur, antibodies will be formed against them because antigens on the fetal RBCs are
“foreign” to the mother. Infant mortality caused by Rh incompatibility can be drastically reduced by
the administration of RhoGam in Rh-negative mothers.
Page 355
1. Granulocytes and agranulocytes. The different types of white blood cells are categorized by the
presence (granulocytes) or absence (agranulocytes) of stained granules in their cytoplasm.
3
2. Leukopenia describes an abnormally low WBC count (less than 5000 WBC/mm of blood).
3
Leukocytosis refers to an abnormally high WBC count (more than 10,000 WBCs/mm of blood).
3. Neutrophils protect the body by ingesting invading microorganisms. Eosinophils protect against
infection caused by parasites and parasitic worms and also are involved in allergic reactions.
Basophils secrete histamine and heparin, monocytes are aggressive phagocytes, and lymphocytes
protect against infections.
4. B lymphocytes secrete antibodies that attach to specific bacteria, viruses, chemical toxins, or other
foreign substances. T lymphocytes do not secrete antibodies, but instead protect us by directly
attacking bacteria, virus infected cells, or cancer cells.
5. Chronic lymphocytic leukemia (adults) and acute lymphocytic leukemia (children).
Page 358
1. A platelet is much smaller than the RBC or WBC. Platelets are tiny cell fragments that have broken
away from a much larger precursor cell. Each platelet is filled with chemicals necessary for triggering
the formation of a blood clot.
2. During the clotting process, as the platelets accumulate, they release clotting factors. If the normal
amount of blood calcium is present, these clotting factors trigger the next step of clotting by
converting prothrombin to thrombin. In the last step, thrombin reacts with fibrinogen to change it to a
fibrous gel called fibrin.
3. A thrombus is a clot that stays in place, whereas an embolus is a clot that circulates through the
bloodstream.
4. Hemophilia and thrombocytopenia
ACTIVE LEARNING
Review Questions
1. Blood plasma consists of water with nutrients, salts, a small amount of oxygen, and cellular wastes
dissolved in it. Hormones and other regulatory chemicals are also dissolved in blood plasma.
2. Albumins help thicken the blood. Globulins are a type of plasma protein that includes antibodies and
helps protect us from infection. Fibrinogen is a soluble blood protein that is converted to insoluble
fibrin during clotting.
3. Serum is blood plasma minus its blood clotting factors, such as fibrinogen, but still contains
antibodies. Plasma is the liquid part of the blood.
4. The two types of connective tissue that form blood cells are myeloid tissue and lymphatic tissue.
Myeloid tissue is also known as red bone marrow and is found chiefly in adults in the sternum, ribs,
and hip bones. It is also found in small amounts in the vertebrae, clavicles, and cranial bones. It
forms all types of blood cells except some lymphocytes and monocytes. Lymphatic tissue is found
chiefly in the lymph nodes, thymus, and spleen. It forms lymphocytes and monocytes not made by
the red bone marrow.
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Answer Keys
5. Red blood cells have a unique shape. They are “caved in” on both sides, so that each one has a thin
center and thicker edges, but has no nucleus. The shape allows a larger surface area for greater,
more efficient exchange of oxygen and carbon dioxide between the blood plasma and the cells.
6. In type A blood, the red blood cells contain the A antigen and the blood plasma contains anti-B
antibodies. In type B blood, the red blood cells contain the B antigen and the blood plasma contains
the anti-A antibodies.
7. If a mother is Rh negative and a baby inherits the Rh positive trait from the father, the Rh factor can
stimulate the mother’s body to form anti-Rh antibodies. If the mother later carries another Rh positive
fetus, the fetus may develop erythroblastosis fetalis. This condition is caused by the mother’s anti-Rh
antibodies reacting with the baby’s Rh positive red blood cells.
8. Aplastic anemia usually results from destruction of bone marrow by a toxic chemical, drugs, radiation,
or cancer. Pernicious anemia results from a dietary deficiency of vitamin B 12 .
9. If whole blood is placed in a test tube and “spun down” in a centrifuge, the heavier formed elements
will settle to the bottom. During this procedure, the red blood cells are forced to the bottom, and the
white blood cells and platelets settle out just above them in a layer called the buffy coat.
10. White blood cells defend the body against microorganisms. Neutrophils and monocytes are WBCs
that engulf microbes. They take them into their cell bodies and digest them in a process called
phagocytosis. Cells that carry on this process are called phagocytes.
11. Lymphocytes are WBCs that protect against infections. There are two types: B lymphocytes and T
lymphocytes. B lymphocytes actively produce specific antibodies that inhibit the growth or functioning
of microbes. T lymphocytes directly attack the microbes and also aid in the functioning of the B
lymphocytes.
12. Eosinophils are granulocytic white blood cells that help protect the body from irritants that cause
allergies. They are also capable of phagocytosis. Basophils also function in allergic reactions. They
secrete a number of important chemicals, such as heparin, which help prevent the formation of blood
clots as blood flows through the blood vessels.
13. Leukopenia refers to an abnormally low number of white blood cells, fewer than 5,000 white blood
cells per cubic millimeter of blood. Leukocytosis refers to an abnormally high number of white blood
cells, more than 10,000 white blood cells per cubic millimeter of blood.
14. Hemophilia is an inherited disorder passed on by the X chromosome; therefore, it is much more
common in men. Hemophilia is characterized by a relative inability to form blood clots. The condition
results from a failure to form the blood clotting factors VIII, IX, or XI. These clotting factors are
necessary to complete the blood clotting process.
15. The first step in blood clot formation begins with some kind of injury to a blood vessel, making a rough
spot on the interior lining. Almost immediately, damaged tissue cells release clotting factors into the
plasma. These factors rapidly react with other factors that are already present in the plasma to form
prothrombin activator. At the same time, platelets become “sticky” at the point of injury and soon
accumulate near the opening of the broken blood vessel, forming a soft, temporary platelet plug. As
the platelets accumulate, they release additional factors, forming more prothrombin activator. If the
normal amount of calcium is present in the plasma, prothrombin activator converts prothrombin,
which is normally found in the plasma, into thrombin. In the last step, thrombin reacts with fibrinogen,
also normally found in the plasma, and changes it into a fibrous gel called fibrin. Fibrin looks like a
tangle of fine threads that trap red blood cells that form the actual blood clot.
16. A thrombus is a blood clot that stays where it is formed. An embolus is a blood clot or part of a blood
clot that has broken free and is circulating in the bloodstream.
Critical Thinking
17. Physicians sometimes prescribe vitamin K before surgery to make sure that the patient’s blood will
clot fast enough to prevent hemorrhage. Vitamin K stimulates liver cells to increase the synthesis of
prothrombin, which allows faster production of thrombin during clotting and thus faster clot formation.
18. Heparin inhibits the conversion of prothrombin into thrombin, which prevents the conversion of
fibrinogen to fibrin, thus preventing the formation of a blood clot.
Page 3 of 12
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Answer Keys
19. The most likely cause would be a blood transfusion with an incompatible blood type. The antibodies
in the transfused blood reacted with the antigens in the recipient’s blood to cause agglutination.
20. The mother usually has not formed any anti-Rh antibodies with a first pregnancy; the reaction is
similar to an allergic reaction. The antibodies made by the mother react to the Rh protein on the
blood cells of the fetus. Because the mother has not been “sensitized” by the Rh protein, she has no
antibodies to cause the reaction; however, in future pregnancies, an Rh positive baby most likely
would be affected.
21. Blood doping is a practice in which athletes will have blood drawn a few weeks before a competition.
The RBCs are thawed and injected back into the athlete. Theoretically, the increased number of
RBCs and hemoglobin would increase oxygen consumption and muscle performance during
exercise. The effects are minimal and the risk of impacting the viscosity (thickness) of blood may
have harmful effects on the athlete.
Chapter Test
1. plasma
2. albumin, globulin, fibrinogen
3. serum
4. red blood cells, white blood cells, platelets
5. myeloid, lymphoid
6. hemoglobin
7. Antigen
8. A and B, neither anti-A nor anti-B
9. B, anti-A
10. O
11. AB
12. erythroblastosis fetalis
13. anemia
14. polycythemia
15. neutrophils
16. B lymphocytes
17. calcium
18. fibrinogen, fibrin
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
K
thrombus
embolus
f. a low number of red blood cells because
of a lack of Vitamin B 12
a. a type of inherited anemia that produces
abnormal hemoglobin and red blood cell
deformities
c. an inherited disorder in which a small
amount of hemoglobin is produced; can be
major or minor
d. an inherited inability to form some blood
clotting factors
e. an abnormally low number of platelets
h. an abnormally high white blood cell count
b. an abnormally low white blood cell count
g. a low number of red blood cells related to
destruction of bone marrow
Case Studies
1. Angela’s physician will probably order a test to determine which, if any, enzymes in Angela’s blood
plasma are abnormally elevated. In this chapter, you learned that transaminase is a plasma enzyme
that increases after a heart attack.
2. The wisest course of action usually involves seeking and following professional medical advice rather
than acting on one’s own initiative. In this case, Yvonne’s actions are not likely to help her because
pernicious anemia is more often caused by a lack of intrinsic factor needed to absorb B 12 into the
blood. If this is true in Yvonne’s case, no matter how many B 12 tablets she takes, she will probably
not absorb enough B 12 to reverse her condition. Her physician would likely recommend an
intramuscular injection of B 12 —a method that bypasses the absorption problem.
3. The actual diagnosis can be made only by a qualified professional, but based on the results given
and the data in Table 13-3 on page 349, a good guess is a type of hemolytic anemia. Most types of
hemolytic anemia, such as sickle-cell anemia and thalassemia, are inherited, so it is possible that you
inherited the same defective gene or genes as your brother. Depending on the exact type, however,
it is unlikely that you would have gotten this far in life without developing some symptoms already.
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Answer Keys
CHAPTER 14
QUICK CHECK
Page 373
1. The atria receive blood from the body and pump it to the ventricles. The ventricles discharge the
blood by pumping it from the heart to the lungs or body.
2. Visceral pericardium or epicardium (inner layer of the pericardium) and parietal pericardium (outer
layer of the pericardium). The endocardium lines the heart chambers.
3. The two pericardial layers slide against each other without friction when the heart beats because
these are serous membranes with moist, not dry, surfaces.
Page 378
1. Contraction of the heart is called systole. Relaxation is called diastole.
2. Pulmonary circulation and systemic circulation
3. The first sound (lub) is caused by the vibration and abrupt closure of the AV valves as the ventricles
contract. The second heart sound (dup) is caused by the closing of both the semilunar valves when
the ventricles undergo diastole.
4. The brief period before ventricular contraction where there is no change in volume occurs because it
takes a moment for the ventricular pressure to overcome the force needed to open the semilunar
valves.
Page 380
1. Sinoatrial node (pacemaker), atrioventricular node (AV node), AV bundle (bundle of His), and
Purkinje fibers (subendocardial fibers)
2. Sinoatrial (SA) node
3. An electrocardiogram is the graphic record of the heart’s electrical activity.
4. P wave, QRS complex, and T wave
Page 385
1. The term dysrhythmia refers to an abnormality of heart rhythm.
2. Tachycardia is a rapid heart rhythm (more than 100 beats per minute), whereas bradycardia is a slow
rhythm (less than 60 beats per minute).
3. Fibrillation may be treated immediately by defibrillation (application of electrical shock). In atrial
fibrillation, a drug such as digoxin (digitalis) may be used to prevent ventricular involvement. In
ventricular fibrillation, epinephrine may be injected into the bloodstream to increase blood pressure
enough to make defibrillation successful. If initial defibrillation is unsuccessful, then drugs that help
dysrhythmia also may be injected into the bloodstream.
4. Atrial ablation is the intentional destruction of heart muscle in a specific location. It is used to treat
atrial fibrillation by eliminating the pathway of abnormal electrical signals.
5. Cardiac output (CO) is the volume of blood pumped by one ventricle per minute. It is determined
mainly by the heart rate (HR) and stroke volume (SV). HR (beat/min) x SV (volume/beat) = CO
(volume/min).
ACTIVE LEARNING
Review Questions
1. The heart is located between the lungs in the lower portion of the mediastinum. About two-thirds of
the heart is to the left of the midline of the body and one-third is to the right of the midline. The heart
is triangular-shaped and the size of a closed fist. The apex, or the blunt point of the lower edge of the
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Quick Check and Active Learning
Answer Keys
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
heart, lies on the diaphragm pointing left. The heart is positioned between the sternum in the front
and the bodies of the thoracic vertebrae behind.
The two upper chambers are called the atria (right and left), which are receiving chambers. The two
lower chambers are called ventricles (right and left), which are discharging chambers.
The myocardium is cardiac muscle tissue. The endocardium is a thin layer of very smooth tissue that
lines the chambers of the heart.
The covering of the heart is called the pericardium. It consists of two layers of fibrous connective
tissue with a small space in between. The inner layer of the pericardium is called the visceral
pericardium, or epicardium, whereas the outer layer is called the parietal pericardium. It fits around
the heart like a loose sac, allowing enough room for the heart to beat. Pericardial fluid lubricates the
heart to reduce the friction when it beats.
Pericarditis is an inflammation of the pericardium. Pericardial effusion occurs when fluid, pus, or
blood accumulates in the space between the visceral and parietal pericardium and may impair the
pumping action of the heart.
Systole is the contraction of the heart muscle. Diastole is relaxation of the heart muscle.
The heart has four valves that keep blood flowing through the heart, preventing backflow. The two
heart valves that separate the atrial chambers from the ventricular chambers are called
atrioventricular (AV) valves. The left AV valve is also called the bicuspid, or mitral valve. The right
AV valve is called the tricuspid valve. The semilunar heart valves are located between the ventricles
and the arteries that carry blood away from the heart. The pulmonary semilunar valve is located
between the right ventricle and the pulmonary artery. The aortic semilunar valve is located between
the left ventricle and the aorta.
Mitral valve prolapse is a condition affecting the bicuspid or mitral valve. A prolapsed mitral valve is
one whose flaps extend back into the left atrium, causing a leaking of the valve.
In a myocardial infarction, a blood clot occludes or plugs up some part of the coronary artery. Blood
cannot pass through the occluded vessel and, therefore, cannot reach the part of the heart muscle it
normally supplies. Deprived of oxygen, these cells are soon damaged or die.
Blood enters the right atrium through the superior and inferior vena cava. The right atrium pumps the
blood through the right AV valve or tricuspid valve and into the right ventricle. The right ventricle
contracts and pushes the blood through the pulmonary semilunar valve into the pulmonary artery,
which carries the blood to the lung. The blood returns from the lung by way of the pulmonary veins,
which empty into the left atrium. The left atrium contracts and pushes the blood through the left AV
valve or bicuspid (mitral) valve and into the left ventricle. The left ventricle contracts and pushes
blood through the aortic semilunar valve into the aorta.
The term angina pectoris is used to describe severe chest pain that occurs when the myocardium is
deprived of adequate oxygen.
Impulse conduction normally starts in the heart’s pacemaker, the sinoatrial node. From there, it
spreads in all directions through the atria, causing the atria to contract. When the impulses reach the
atrioventricular node, it relays the impulses by way of the atrioventricular bundle or the bundle of His
and Purkinje fibers to the ventricles, causing them to contract.
There are two kinds of heart block. In AV node heart block, impulses are blocked from getting
through to the ventricles, resulting in the ventricles contracting at a much slower rate than normal. On
an ECG, there may be a large distance between the P wave and the R peak of the QRS complex.
Complete heart block occurs when the P waves do not match up with the QRS complex at all. There
is no relationship between atrial contraction and ventricular contraction. Bradycardia refers to a heart
rate of fewer than 60 beats per minute (slow heart rhythm). Tachycardia refers to a heart rate of
greater than 100 beats per minute (rapid heart rhythm).
Fibrillation is a condition in which cardiac muscle fibers contract out of step with each other.
Ventricular fibrillation is more dangerous than atrial fibrillation and is an immediately life-threatening
situation.
The factors that affect heart rate are the heart’s pacemaker and the autonomic nervous system. The
factors that affect stroke volume are the venous return and the strength of myocardial contraction.
Page 6 of 12
Quick Check and Active Learning
Answer Keys
16. Stroke volume refers to the volume of blood ejected from the ventricles during each heartbeat.
Cardiac output is the volume of blood pumped by one ventricle per minute. The average amount of
blood pumped per minute is about 5 L in a normal resting adult.
Critical Thinking
17. A normal ECG tracing has three characteristic deflections and they are the P wave, QRS complex,
and T wave. These deflections represent the electrical activity that regulates the contraction or
relaxation of the atria and ventricles. The term depolarization describes the electrical activity that
triggers the contraction of the heart muscle. Repolarization begins just before the relaxation phase of
cardiac muscle activity. The P wave occurs with depolarization of the atria. The QRS complex
occurs as a result of depolarization of the ventricles. The T wave results from the repolarization of
the ventricles.
18. Right-sided heart failure often results from the progression of disease that begins in the left side of
the heart; this results in reduced pumping of blood returning from the lungs. Blood backs up into
pulmonary circulation and then into the right heart, causing an increase in pressure that the right side
of the heart cannot overcome.
19. Danny’s cardiac output is 5040 ml or 5.04 L. HR (72) × SV (70) = CO: 5040 ml (5.04 L).
20. An angiography is a special type of radiography used to visualize arteries. A radiopaque dye, which
cannot be penetrated by x-rays, is injected into an artery to better visualize vessels that would
otherwise be invisible in a radiograph.
Chapter Test
1. Ventricles
2. Atria
3. myocardium
4. interventricular septum
5. endocardium
6. pericarditis
7. systole
8. chordae tendineae
9. tricuspid (right atrioventricular)
10. sinoatrial node
11. Purkinje fibers
12. QRS complex
13. stroke volume
14. cardiac output
15. a. left atrium 7
b. tricuspid valve (right atrioventricular valve) 2
c. right ventricle 3
d. pulmonary vein 6
e. aortic semilunar valve 10
f. mitral valve (left atrioventricular valve) 8
g. left ventricle 9
h. pulmonary artery 5
i. right atrium 1
j. pulmonary semilunar valve 4
16. f. inflammation of the pericardium
17. i. a condition that allows blood to leak back into the left atrium when the left ventricle contracts
18. a. damage to the heart cells due to a lack of blood flow
19. h. severe chest pain that occurs when the heart muscle is deprived of oxygen
Page 7 of 12
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Answer Keys
20. g. a condition in which contraction impulses are prevented from getting through to the ventricles
21. b. slow heart rhythm
22. d. rapid heart rhythm
23. c. a condition in which the cardiac muscles contract out of step with each other
24. e. also called left heart failure
Case Studies
1. The large spikes (tall waves) on the ECG monitor are probably the QRS complexes, which represent
depolarization of the ventricular myocardium—the point at which your friend’s ventricles are about to
pump blood out of the heart during each cardiac cycle. The observed change probably resulted from
the electrical “noise” produced by a muscular movement made by the patient. If so, the ECG pattern
will return to normal when she stops moving. However, the sudden change may be due to ventricular
fibrillation, a judgment best made by a trained professional. As with any medical emergency, the first
thing to do after determining that there is a problem is to summon help. First aid for such a problem
may involve CPR. (Have you had your CPR refresher course this year?). A defibrillator or other
treatments may be used to correct your friend’s problem.
2. Vivian’s mitral valve prolapse (MVP) is a condition in which the left atrioventricular (mitral) valve
billows backward into the left atrium. Because of this defect, the edges of the mitral valve may not
meet to form a tight seal. Thus, blood may leak back into the left atrium during contraction of the left
ventricle. The severity of Vivian’s condition depends largely on the amount of blood leakage that
occurs.
3. Your uncle’s heart probably has blockage of some of the major coronary arteries. This blockage
could be due to a number of factors, the most likely of which is atherosclerosis. In this condition, fatty
deposits form in the walls of arteries, decreasing the diameter of the lumen and reducing blood flow.
Without correction, your uncle may suffer a myocardial infarction resulting from oxygen deprivation of
heart muscle supplied by the affected arteries. The triple-bypass surgery will graft new vessels into
your uncle’s coronary circulation to route blood around the blocked areas (Figure 14-8 on page 376).
Page 8 of 12
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Answer Keys
CHAPTER 15
QUICK CHECK
Page 394
1. Arteries, veins, and capillaries are the main types of blood vessels in the body and differ in structure.
There are three coats or layers found in both arteries and veins. The muscle layer (tunica media) is
much thicker in arteries than it is in veins. The outer layer (tunica externa) is thinner in arteries.
Veins have a unique structural feature (one-way valves) that prevents the back flow of blood.
Capillaries are composed of only one layer of flat, endothelial cells.
2. The thicker muscular layer of the artery is able to resist great pressures generated by ventricular
systole.
3. Precapillary sphincters guard the entrances to the capillaries and determine how much blood will flow
into each capillary.
4. Capillaries function as exchange vessels. Glucose and oxygen move out of the blood in capillaries
into interstitial fluid and then on into cells. Carbon dioxide and other substances move in the opposite
direction.
Page 399
1. Arteriosclerosis is hardening of the arteries. Arteriosclerosis is characterized by a thickening of
arterial walls that progresses to hardening as calcium deposits form.
2. An aneurysm is a section of an artery that has become abnormally weakened because of a
weakening of the arterial wall.
3. Varicose veins can be caused by the force of gravity slowing the return of venous blood to the heart,
causing blood-engorged veins to dilate. As the veins dilate, the distance between the flaps of venous
valves widens, eventually making them incompetent (leaky). These leaky veins cause more pooling
of blood in affected veins.
Page 402
1. Systemic blood circulation is when blood flows from the left ventricle of the heart through blood
vessels to all parts of the body and back to the right atrium. In pulmonary circulation, blood flow
moves from the right atrium to the right ventricle and then to the pulmonary artery to lung arterioles
and capillaries. There, the exchange of oxygen and carbon dioxide takes place. The oxygenated
blood then flows through lung venules into the pulmonary veins and returns to the left atrium.
2. Hepatic portal circulation is the route of blood flow through the liver.
3. The fetus contains several structures that allow it to secure oxygen and food from maternal blood
instead of from its own lungs and digestive organs. These include umbilical arteries and veins
(umbilical cord), ductus venosus, foramen ovale, and ductus arteriosus.
4. Cyanosis is a bluish tissue coloration resulting from a lack of oxygen in the system.
Page 406
1. The blood pressure gradient is the difference between the average or mean blood pressure in the
aorta and the blood pressure at the termination of the venae cavae where they join the right atrium of
the heart. When a blood pressure gradient is present, blood circulates; conversely, when a blood
pressure gradient is not present, blood does not circulate.
2. Blood volume, the strength of each heart contraction, heart rate, and blood viscosity (the thickness of
blood)
3. No one’s blood pressure stays the same all the time. It increases or decreases depending on the
activity of the individual. Strenuous exercise demands more oxygen and food to be sent to muscles.
Increased blood pressure increases circulation to bring more blood to muscles, thus supplying them
with the needed oxygen and food.
Page 9 of 12
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Answer Keys
Page 409
1. Superficial temporal artery (front of ear), facial artery (lower margin of the mandible at a point below
the corner of the mouth), carotid artery ( neck), axilla (armpit), brachial artery (bend of the elbow),
radial artery (wrist), femoral artery (groin), popliteal artery (behind and just proximal to the knee), and
dorsalis pedis artery (front surface of the foot)
2. As one gets older, the blood vessels become less compliant, and there is a higher incidence of
atherosclerotic plaque build-up, and therefore a higher incidence of hypertension.
3. Cardiogenic shock results from any type of heart failure; blood flow to the tissues of the body
decreases or stops. Hypovolemic shock results from loss of blood volume in the blood vessels.
Neurogenic shock occurs as a result of widespread dilation of blood vessels caused by an imbalance
in autonomic stimulation of smooth muscles in vessel walls. Anaphylactic shock results from an
allergic reaction that causes vessel dilation, and septic shock results from complications of septicemia
when toxins are released in blood resulting in dilation.
ACTIVE LEARNING
Review Questions
1. Arteries carry blood away from the heart and have a thick tunica media to deal with high blood
pressure. Veins carry blood toward the heart, have a thinner tunica media, and have one-way valves
to help return blood to the heart. Capillaries are only one cell-layer thick to allow for the exchange of
material between the blood and tissues. They carry blood from the arterioles to the venules.
2. The three tissue layers that make up arteries and veins are (1) tunica externa, which is the outermost
layer of elastic tissue; (2) tunica media, the middle layer made of smooth muscle with some elastic
tissue; and (3) tunica intima, the innermost layer of endothelial cells.
3. Arteriosclerosis is a vascular disease that occludes arteries and weakens arterial walls; it is also
called “hardening of the arteries.” It is characterized by thickening of arterial walls that progresses to
hardening as calcium deposits form. The thickening and calcification reduce the flow of blood to the
tissues. If the blood flow is reduced too much, ischemia results.
4. Ischemia is a decreased supply of blood to tissues that can lead to death of the cells. Gangrene is a
large section of dead and decaying cells.
5. Arteriosclerosis can be treated by drugs called vasodilators that trigger the smooth muscles of the
arterial walls to relax. Some cases can be treated by mechanically opening the affected area of an
artery with a procedure called an angioplasty.
6. Phlebitis is an inflammation of a vein.
7. Systemic circulation begins in the left ventricle when blood is pumped out to the aorta. From there, it
flows into arteries that carry it into the tissues and organs of the body. Within each structure, blood
moves from arteries to arterioles to capillaries, where material is exchanged between the blood and
the cells. Blood then flows out of the tissues into venules and then into veins that eventually join to
either the superior or inferior vena cava, draining into the right atrium. Pulmonary circulation begins
when the right ventricle contracts and pumps the blood through the pulmonary artery to the capillaries
of the lung. The blood gives up its carbon dioxide and receives oxygen, returning to the left atrium of
the heart by way of the pulmonary vein.
8. If the foramen ovale failed to close at the time of birth, blood would continue to bypass the pulmonary
circulation. This would result in a light-skinned baby that may appear bluish (cyanosis) because of
the lack of oxygen in the systemic arterial blood.
Page 10 of 12
Quick Check and Active Learning
Answer Keys
9. (1) Blood volume has a direct relationship to blood pressure. The more volume in the arteries, the
higher the blood pressure. The less volume in the arteries, the lower the blood pressure. (2)
Strength of heart contractions forces more blood into the arteries and has the effect of increasing the
blood volume in the arteries. The stronger the heartbeat, the higher the blood pressure. The weaker
the heartbeat, the lower the blood pressure. (3) Heart rate can either increase or decrease the
volume of blood being pumped into the arteries. The increase in the rate of the heartbeat increases
blood pressure only if the stroke volume does not decrease sharply when the heart rate increases.
(4) Blood viscosity refers to the thickness of the blood. If blood viscosity increases, so will the
pressure within the arteries.
10. Central venous pressure is the venous blood pressure within the right atrium. This pressure level is
important because it influences the pressure that exists in the large peripheral veins. If the heart
beats strongly, the central venous pressure is low as blood enters and leaves the heart efficiently.
However, if the heart is weakened, central venous pressure increases and the flow of blood into the
right atrium is slowed.
11. Five mechanisms that help keep venous blood moving back to the heart include (1) the continued
beating of the heart; (2) adequate blood pressure in the arteries; (3) semilunar valves in the veins that
keep blood moving in only one direction; (4) contraction of skeletal muscles that squeeze veins; and
(5) changing pressures in the chest cavity during breathing.
12. Circulatory shock refers to the failure of the circulatory system to adequately deliver oxygen to the
tissues, resulting in the impairment of cell function throughout the body. If left untreated, circulatory
shock may lead to death. The five types of circulatory shock are (1) cardiogenic shock, resulting from
any type of heart failure; (2) hypovolemic shock, resulting from loss of blood volume in the vessels;
(3) neurogenic shock, resulting from widespread dilation of vessels caused by an imbalance in
nervous control of the muscles in blood vessel walls; (4) anaphylactic shock, resulting from an acute
allergic reaction; and (5) septic shock, resulting from complications of toxins released into the blood
during a bacterial infection.
Critical Thinking
13. A positive feedback mechanism is one in which a deviation from the norm or set point causes a
further deviation. People who stand a great deal tend to have varicose veins because the force of
gravity slows the blood return to the heart. This puts pressure on the walls of the veins and causes
the walls to stretch. When this occurs, the flaps of the semilunar valves of the veins no longer meet,
which allows more blood to pool in the vein, causing the walls to widen further. This makes the valve
even more incompetent. This becomes a positive feedback mechanism.
14. Hepatic portal circulation refers to the route of blood flow through the liver. Veins from the spleen,
stomach, pancreas, gallbladder, and intestine empty into the hepatic portal vein rather than the
inferior vena cava. The blood passes through a second set of capillaries in the liver before returning
to the heart; this is different from normal circulation. This passage of blood through the liver allows it
to absorb some of the products of digestion to help maintain the homeostasis of nutrients in the
blood. It is also able to detoxify toxins that may have been absorbed into the blood.
15. High glucose levels trigger the secretion of insulin from the pancreatic islets. Influenced by insulin,
liver cells remove the excess glucose and store it as glycogen. Therefore, blood leaving the liver
usually has a somewhat normal blood glucose concentration.
16. Fetal circulation differs from postnatal circulation in that before birth, the baby secures oxygen and
nutrients from maternal blood instead of from its own lungs and digestive organs. Because the
baby’s liver, lungs, and other vital organs are immature, exchange of oxygen and nutrients occurs
between fetal and maternal blood as the umbilical cord carries fetal blood to the placenta by way of
the two umbilical arteries, where exchange occurs, and then returns the blood to the baby by one
umbilical vein. This ductus venosus serves as a shunt that allows blood returning from the placenta
to bypass the immature liver and pass directly into the inferior vena cava. The foramen ovale shunts
blood from the right atrium into the left atrium and the ductus arteriosus connects the aorta and
pulmonary artery. Based on the environment of the fetus and the unique functional makeup of the
mother and developing baby, circulation is more efficient.
Page 11 of 12
Quick Check and Active Learning
Answer Keys
Chapter Test
1. veins
2. capillaries
3. tunica intima
4. aneurysm
5. pulmonary
6. polycythemia
7. foramen ovale, ductus arteriosus
8. blood viscosity, heart rate
9. f. also called “hardening of the arteries”
10. a. cell death caused by ischemia
12. j. a section of an artery that has widened due to a weakening of the arterial wall
12. b. dilated, blood-engorged veins, usually found in the legs
13. i. inflammation of a vein
14. c. circulatory shock caused by heart failure
15. h. circulatory shock due to loss of blood volume
16. d. circulatory shock that is a complication of septicemia
17. e. circulatory shock caused by an acute allergic reaction
18. g. circulatory shock caused by autonomic stimulation of the smooth muscles in the blood vessels
Case Studies
1. In Chapter 2, in the Blood Lipoproteins box on pages 34-35, it states that exercise increases the ratio
of “good” cholesterol, thus decreasing the ratio of the “bad” cholesterol that causes atherosclerosis.
Atherosclerosis, which develops into hardening of the arteries (arteriosclerosis), may block vessels
and cause myocardial infarction, ischemia or necrosis of other tissues, aneurysms, CVAs, and other
serious problems.
2. Advanced atherosclerosis of a leg artery may reduce blood flow to skeletal muscles in the leg,
enough to make it difficult for them to get oxygen during walking. The muscles will use anaerobic
respiration, which increases lactic acid levels and causes a burning pain often associated with muscle
fatigue. Leo’s physician has many choices of treatment. One choice would be to use vasodilator
drugs, which will relax and expand the affected artery and thus improve blood flow. Another choice is
angioplasty, in which the obstruction is mechanically altered to improve blood flow.
3. To reach the mitral (left AV) valve from the femoral artery, the tip must pass superiorly through the
femoral artery, external iliac artery, abdominal aorta, thoracic aorta, arch of the aorta, passed the
aortic valve, and through the left atrium (Figure 15-3 on page 395).
Page 12 of 12