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Physiology chapter 13

Terms in this set (137)

Keeping blood on the left side of the heart from mixing with the blood on the right side is a 1) function of what structure(s)?
A) septum
The primary site of exchange between blood and interstitial fluid occurs across what type of blood 2) vessel?
E) capillaries
When blood moves through the body it travels in a circular pattern. The general pattern of blood 3) flow follows which sequence of vessels as it leaves the heart?
C) arteries, arterioles, capillaries, venules, veins
Although blood is a fluid, nearly half its volume is composed of cells. The most numerous cells are 4) ________. The remainder of the cells are ________, which help the body defend itself against
A) erythrocytes
The circulatory system consists of two divisions and is supplied with blood by different sides of the 5) heart. The right heart supplies blood to the ________ circuit, whereas the left heart supplies blood
to the ________ circuit.
D) pulmonary : systemic
6) Which statement best describes parallel flow in the circulatory system?
D) The organs of the body are arranged in a parallel circuit to allow adequate flow and pressure
to all body systems and maintain homeostasis of blood pressure.
7) Blood supply to the heart comes from
C) coronary arteries.
8) Which of the following statements best describes a portal system?
B) Blood flows from one capillary bed to another, bypassing general circulation.
9) What structure separates the thoracic cavity from the abdominal cavity?
A) diaphragm
10) Which chamber of the heart has the thickest musculature?
E) Both ventricles have equal thickness and are thicker than the atria.
11) The opening and closure of the atrioventricular and semilunar valves is driven by
A) differences in pressure across the valve.
12) Closure of the atrioventricular valve occurs when
D) pressure inside the ventricle is greater than pressure inside the atrium.
13) Which of the following statements best describes the function of the chordae tendineae?
C) They pull downward on the valve cusps, thereby preventing the AV valves from being
pushed into the atria (prolapsing).
14) What is the primary function of the AV and semilunar valves?
D) to permit blood to flow forward while preventing it from flowing backward
Whereas the contractile activity of skeletal muscle is called ________, that of cardiac muscle is 15) ________ because the contraction originates within the musculature itself.
C) neurogenic : myogenic
16) What two major regions of the heart contain a concentration of pacemaker cells?
B) sinoatrial node and atrioventricular node
17) The term autorhythmicity refers to the heart's ability to
E) generate its own contractile cycle.
What structure provides the pathway for the movement of electrical current between the cells of 18) the conduction pathway and the ventricular muscle fibers?
A) desmosomes B) gap junctions C) funny channels
D) sodium channels
E) potassium channels
19) Which of the following is the correct conduction pathway through the heart?
C) SA node, AV node, bundle of His, bundle branches, Purkinje fibers
20) Conduction through which of the following is slow to allow atria to contract before the ventricles?
E) AV node
21) Why do AV nodal cells NOT determine the heart rate under normal circumstances?
C) As depolarization initiated in the SA node reaches the AV node, it leaves the AV node in a
refractory state.
Normal resting heart rate is around 70 beats per minute due to the SA node. If the SA node fails, 22) what would you expect the heart beats per minute to be?
C) 50 beats per minute
If both the SA node and the AV node fail, what would be the expected outcome of impulse rate 23) within the heart?
C) The rate would be 30-40 beats per minute due to the concentration of pacemaker cells in the
Purkinje fibers.
24) The rapid depolarization phase of a pacemaker cell action potential is caused by movement of
B) calcium through L-type channels.
Which of the following is responsible for the rapid depolarization phase of an action potential 25) within the pacemaker cells?
A) a decrease in PK B) an increase in PNa C) an increase in PCa
D) an increase in PK E) a decrease in PNa
26) Which of the following is responsible for the repolarization of pacemaker cells?
C) an increase in PK
27) What causes the rapid depolarization phase of a contractile cell action potential?
D) sodium movement into the cell
28) During repolarization (phase 3) of a contractile cell action potential,
C) only potassium permeability is increased.
29) Which of the following ion channels does NOT participate in the contractile cell action potential?
E) type T calcium channels
30) Which of the following is NOT a part of the excitation-contraction coupling in cardiac muscle?
A) Calcium binds to calmodulin in the cytosol.
What is the function of the sodium-calcium exchanger in cardiac muscle?
A) remove calcium from the cytosol by transporting it to the extracellular fluid thereby relaxing
the muscle
32) Which of the following components of an ECG represents atrial depolarization?
A) P wave
33) Which of the following components of an ECG represents ventricular depolarization?
B) QRS complex
34) Which of the following components of an ECG represents ventricular repolarization?
C) T wave
35) Which statement best describes why atrial depolarization is usually not detected on a normal ECG?
B) It occurs at the same time as the QRS complex.
The Q-T interval is the time from the onset of the QRS complex to the end of the T wave which 36) measures
B) the time of ventricular systole.
The T-Q segment is the time from the end of the T wave to the beginning of the QRS complex 37) which measures the time
E) of ventricular diastole.
38) The R-R interval is the time between the peaks of two successive QRS complexes and represents
C) the amount of time between heartbeats.
If damage to the AV node slowed down conduction through this tissue, what would be observed 39) on an ECG?
C) a longer PR interval
40) In an ECG recording, the RR interval is 0.5 seconds. What is the heart rate?
D) 120 beats/min
41) Which of the following describes second-degree heart block?
D) Not every atrial contraction is followed by a ventricular contraction.
42) Which statement best describes why clinicians use a defibrillator?
B) The applied current depolarizes all the muscle cells at the same time, returning synchronous
electrical activity to the heart
43) During isovolumetric relaxation,
C) the AV and semilunar valves are closed and ventricular pressure is decreasing.
44) What is occurring during ventricular ejection?
E) The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles.
45) Which of the following is TRUE of the ventricular filling phase of the cardiac cycle?
B) Ventricular pressure is less than aortic pressure.
What phase of the cardiac cycle is the heart in when all four valves of the heart are closed and 46) ventricular pressure is building, but is not yet great enough to open a valve?
C) isovolumetric contraction
47) During which phase of the cardiac cycle are all four heart valves open?
E) none
48) Ejection of blood from the right ventricle will continue until
E) pressure in the pulmonary artery is greater than pressure in the right ventricle.
49) The increase in ventricular volume early in diastole reflects the
C) passive movement of blood through the atrium and into the ventricle.
50) The small increase in ventricular pressure observed late in diastole is caused by
B) atrial contraction.
51) Blood is ejected from the left ventricle once pressure within the
A) ventricle is greater than pressure within the aorta.
52) The increased aortic pressure that occurs during systole reflects a(n)
C) increased volume of blood in the aorta.
53) The end-diastolic volume minus the end-systolic volume is the
B) stroke volume.
The volume of blood ejected from the ventricle with each contraction can be described by the 54) equation
B) (end-diastolic volume) - (end-systolic volume).
Given end-diastolic volume = 130 mL and end-systolic volume = 50 mL, what is the stroke volume 55) and ejection fraction?
B) SV = 80 mL, EF = 0.61
56) What causes the sounds that one hears as the heart beats?
E) the turbulence created as the valves close
57) Cardiac output is determined by what two variables?
D) heart rate and stroke volume
Regulation of the heart (or any organ or tissue) by neural input, circulating hormones, or any other 58) factor originating from outside the organ is referred to as ________ control.
C) extrinsic
Which of the following structures is poorly innervated by the parasympathetic nervous system and, 59) therefore, an increase in parasympathetic activity has little effect on this structure?
A) ventricles
60) The SA node is innervated by the
D) sympathetic and parasympathetic nervous systems.
61) Which of the following is an effect of parasympathetic activity to the heart?
A) The rate of spontaneous depolarization in SA nodal cells decreases.
62) Which of the following is a FALSE statement about sympathetic activity to the SA node?
B) Potassium channel closing is enhanced.
63) Under resting conditions, heart rate is primarily under the control of what control system?
A) the parasympathetic nervous system
64) An increase in heart rate can be mediated through which of the following?
E) a decrease in parasympathetic activity and an increase in sympathetic activity
65) Which of the following would NOT result from an increase in ventricular contractility?
C) decreased end-diastolic volume
66) Which of the following best describes the effect of sympathetic activity on ventricular contractile 66) cells?
D) The rates of contraction and relaxation and the force of contraction all increase.
67) Which of the following describes the effect of end-diastolic volume on stroke volume?
B) An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum, increasing the strength of contraction and thereby increasing stroke volume.
68) Which of the following variables is NOT an intrinsic factor that alters cardiac function?
B) hormonal stimulation
69) Starling curves plot ________ against ________.
D) stroke volume : end-diastolic volume
The preload is approximately the same as the ________ pressure.
D) end-diastolic
71) Which of the following factors determines preload?
A) heart rate and venous return
72) An increase in venous return would result in a(n)
A) increased end-diastolic volume.
73) Which of the following variables is NOT involved in determining ventricular preload?
E) afterload
74) A decrease in afterload will lead to which of the following?
B) increased stroke volume
75) Which of the following decreases heart rate?
A) increase in parasympathetic activity
76) Which heart structure receives deoxygenated blood from veins?
A) right atrium
77) Which heart structure receives blood from the pulmonary veins?
C) left atrium
78) Where is the SA node located?
A) right atrium
79) The mitral valve separates what chamber from its associated ventricle?
C) left atrium
80) What chamber empties into the aorta?
B) left ventricle
81) What chamber has the thickest myocardium?
B) left ventricle
82) During isovolumetric contraction, which chamber has the greatest pressure?
B) left ventricle
83) Which chamber is connected to the pulmonary arteries?
D) right ventricle
Which channel type allows sodium movement into the cell during the early spontaneous 84) depolarization in autorhythmic cells?
C) funny channels
Which channel type allows calcium movement into the cell during the late spontaneous 85) depolarization in autorhythmic cells?
B) T-type calcium channels
Which channel type allows ion movement out of the cell during repolarization of the autorhythmic 86) cells?
A) potassium channels
Which channel type is responsible for ion movement during the depolarization phase of the 87) autorhythmic cell action potential?
D) L-type calcium channels
88) What channels open during the plateau phase of the cardiac contractile cell action potential?
D) L-type calcium channels
Opening of what channels is responsible for the depolarization phase of the cardiac contractile cell 89) action potential?
E) voltage-gated sodium channels
90) Which component of an ECG represents ventricular depolarization?
E) QRS complex
91) Which component of an ECG represents atrial depolarization?
A) P wave
92) Which component of an ECG represents ventricular repolarization?
C) T wave
93) Which component of an ECG represents ventricular systole?
D) Q-T interval
94) Which component of an ECG represents ventricular diastole?
E) T-Q segment
95) Which component of an ECG represents the AV nodal conduction time?
B) P-R interval
In what phase is the cardiac cycle when all four valves are closed and pressure in the ventricle is 96) decreasing?
D) isovolumetric relaxation
97) In what phase of the cardiac cycle does ventricular pressure exceed aortic pressure?
E) ventricular ejection
98) In what phase is the cardiac cycle when the AV valves are open and semilunar valves are closed?
B) ventricular filling
99) In what phase is the cardiac cycle when the semilunar valves are open and AV valves are closed?
E) ventricular ejection
100) The second heart sound coincides with the beginning of which period in the cardiac cycle?
D) isovolumetric relaxation
101) Blood returns to the left atrium via what blood vessels?
B) pulmonary veins
102) What are the three layers of the heart, from inside to outside?
B) endothelium, myocardium, and epicardium
103) Blood is moved through the pulmonary vasculature by pressure generated within the
A) right ventricle.
What component of the conduction pathway transmits the action potential to the ventricular 104) contractile cells?
B) Purkinje fibers
105) What is the pacemaker of the heart?
C) SA node
The initial depolarization that occurs in pacemaker cells is caused by closing of ________ channels 106) and opening of ________ channels.
C) potassium : funny
The depolarization of the action potential in the pacemaker cells is driven by the rapid influx of 107) ________ ions through ________ channels.
D) calcium : L-type calcium
The period of ventricular contraction is called ________, whereas the period of ventricular 108) relaxation is called ________.
C) systole : diastole
109) The P wave of the electrocardiogram is created by
B) atrial depolarization.
110) The repolarization of the ventricle is reflected in the ________ of the electrocardiogram.
A) T wave
111) The volume of blood that is pumped by the heart every minute is determined by the equation
B) CO = HR × SV.
What is the equation relating stroke volume (SV), end-diastolic volume (EDV), and end-stroke 112) volume (ESV)?
A) SV = EDV - ESV B) SV = EDV × ESV
113) All veins return blood to the heart.
True
114) All veins contain deoxygenated blood.
False
115) Deoxygenated blood is blue.
False
The muscular wall of the right ventricle is thicker than that of the left ventricle because it develops 116) a greater pressure in order to deliver blood to the organs of the body.
False
Arteries are vessels that always carry oxygenated blood. 117)
False
Ischemia is a condition in which blood flow in a tissue is insufficient to keep up with metabolic 118) demand.
True
A heart attack is also known as myocardial ischemia.
False
120) On average, women have anatomically larger hearts than men.
False
Prolapse involves improper alignment of the atrioventricular valve such that one or more of the 121) cusps are pushed into the atrium by the pressure developed in the ventricle.
True
The contractile cycle of the heart normally originates from a pacemaker cell within the sinoatrial 122) node.
True
123) Contractile activity of cardiac muscle is neurogenic
False
124) Ventricular contraction begins at the top of the heart and travels downward to its apex.
False
Calcium movement into the cell causes the rapid depolarization of the autorhythmic cell action 125) potential, whereas sodium movement into the cell causes the rapid depolarization of the contractile
cell action potential.
False
During recording of an ECG, a depolarization that travels toward a positive lead will cause an 126) upward deflection.
True
127) An electrocardiogram recording is the same thing as an action potential
False
128) Abnormal electrical activity of the heart is called myocardial infarction.
False
129) An abnormally slow firing of the SA node causes bradycardia.
True
130) Atrial fibrillation is usually fatal if not treated immediately.
False
131) The cardiac cycle represents one heartbeat.
True
Calcium entering the cell during the plateau phase of the ventricular cell action potential triggers 132) calcium release from the sarcoplasmic reticulum.
True
133) Arteries have a high compliance compared to veins.
False
134) The resting cardiac output for both the left and right ventricles is approximately 5.0 liters/minute.
True
Age, general health, level of muscular activity and emotional state can all affect cardiac output and 135) heart rate.
True
136) The heart is regulated by both intrinsic and extrinsic mechanisms.
True
Given a constant pressure, the greater the radius of the vessel, the greater the tension on the vessel 137) walls.
True
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