Ch 18 - The Heart Flashcards
1
Q
Heart muscle
A
Myocardium
2
Q
Serous layer covering the heart muscle
A
Epicardium
3
Q
The outermost layer of the serous pericardium
A
Parietal layer
4
Q
SA node
A
Pacemaker of the heart
5
Q
Found in the interventricular septum
A
AV bundle
6
Q
Network found in the ventricular myocardium
A
Purkinje fibers
7
Q
The point in the conduction system of the heart where the impulse is delayed
A
AV node
8
Q
Prevents backflow into the left ventricle
A
Aortic valve
9
Q
Prevents backflow into the right atrium
A
Tricuspid valve
10
Q
Prevents backflow into the left atrium
A
Bicuspid valve
11
Q
Prevents backflow into the right ventricle
A
Pulmonary valves
12
Q
AV valve with 2 flaps
A
Bicuspid valve
13
Q
AV valve with 3 flaps
A
Tricuspid valve
14
Q
True or false? The myocardium receives its blood supply from the coronary arteries.
A
True
15
Q
True or false? Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.
A
False
16
Q
Endocardium
A
The inner lining of the heart
17
Q
True or false? Proper function of the heart is dependent upon blood levels of ionic sodium
A
False
18
Q
True or false? Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues
A
True
19
Q
True or false? Tissues damaged by myocardial infarction (heart attack) are replaced by connective tissue
A
True
20
Q
True or false? The left side of the heart pumps the same volume of blood as the right
A
True
21
Q
True or false? Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart
A
True
22
Q
True or false? The mitral valve has chordae but the tricuspid valve does not
A
False
23
Q
True or false? Trabeculae carneae are found in the ventricles and never the atria
A
True
24
Q
True or false? The “lub” sounds of the heart are valuable in diagnosis because they provide information about the function of the heart’s pulmonary and aortic valves
A
False
25
True or false? Autonomic regulation of heart rate is via 2 reflex centers found in the pons
False
26
True or false? The dicrotic notch refers to the brief rise in pressure caused by the closure of the AV valves during ventricular systole
False
27
True or false? An ECG provides direct information about valve function
False
28
True or false? As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve
True
29
True or false? Proxysmal atrial tachycardia is characterized by bursts of atrial contractions with little pause between them
True
30
Normal heart sounds are caused by _______________.
Closure of the heart valves
31
Cardiac reserve can be improved by ______________________.
Regular exercise
32
Hemorrhage with a large loss of blood causes _______________________ due to change in cardiac output
A lowering of blood pressure
33
The left ventricular wall of the heart is thicker than the right wall in order to do what?
Pump blood with greater pressure
34
Damage to the __________ is referred to as heart block
AV node
35
The P wave of a normal electrocardiogram indicates what?
Atrial depolarization
36
Blood within the pulmonary veins returns to the ___________________
Left atrium
37
Small muscle masses attached to the chordae tendineae are the ________________________
Papillary muscles
38
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ___________________________.
Angina pectoris
39
To auscultate the aortic valve, you would place your stethoscope __________________.
In the second intercostal space to the right of the sternum
40
The source of blood carried to capillaries in the myocardium would be the ________________________.
Coronary arteries
41
When the heart is beating at a rate of 75 times per minute, the duration of one cardiac cycle is _______ seconds.
0.8
42
Age, gender, and body temperature influence heart rate, while _______ does not
Skin color
43
Atherosclerosis, decline in cardiac reserve, and fibrosis of cardiac muscle are all age-related changes affecting the heart, while ____________ does NOT.
Thinning of the valve flaps
44
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ___________.
Decreased delivery of oxygen
45
Cardiac muscle cells are like skeletal muscle cells in that they ________________.
Have I and A bands
46
Cardiac output is about _________ L/min
5.25
47
The pericardial cavity contains a lubricating fluid called ________________
Serous fluid
48
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells _______________ might occur, which would stop the heart's pumping action
Tetanic contractions
49
Norepinephrine acts on the heart by ______________.
Causing threshold to be reached more quickly
50
If the vagal nerves to the heart were cut, the result would be that ___________
The heart rate would increase by about 25 beats per minute
51
Foramen ovale connects the two atria in the ____________________
Fetal heart
52
The stroke volume for a normal resting heart is _________ mL/beat
70
53
Which vessel of the heart receives blood during right ventricular systole?
Pulmonary trunk
54
Blood ejected from the ventricles enters ____________ during ventricular systole
Both the aorta and pulmonary trunk
55
AV node, bundle of His, and SA node are part of the conduction system of the heart, while the _____ is NOT
AV valve
56
The tricuspid valve is closed when __________
the ventricle is in systole
57
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ____________
Noticing the thickness of the ventricle walls
58
The AV valves are supported by ___________ so that they do not blow back up into the atria during ventricular contraction
Chordae tendineae
59
The _____________ as applied to cardiac muscle means that the entire heart contracts as a unit or it does not contract at all
All-or-none law
60
The ___________ is the layer of the heart that actually contracts
Myocardium
61
Compared to skeletal muscle, cardiac muscle has ________________ that allow it to act as a functional syncytium
Gap junctions
62
Cardiac muscle has sarcomeres with _________
A bands and I bands
63
The deflection waves in an ECG tracing include the _____________, which indicates ventricular repolarization
T wave
64
During the period of ventricular filling, blood flows passively through the atria and the _____________
Open AV valves
65
The effect of endurance-type athletic training may be to lower the resting heart rate. This phenomenon is caused by _____________ of the heart muscle
Hypertrophy
66
The second heart sound is heard during the ___________ phase of the cardiac cycle
Isovolumetric relaxation
67
The time of the day most hazardous for heart attacks is ________________
Morning
68
If a significant amount of connective tissue were to develop connecting the visceral and parietal pericardial layers together, the likely consequence would be __________
Interference with normal mechanical cardiac activity
69
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________ and heart rate would increase
Threshold is reached more quickly
70
A ___________ increases end diastolic volume, stroke volume, and force of contraction
Slow heart rate
71
During contraction of heart muscle cells, some calcium enters the cell from the _______________ and triggers the release of larger amounts of calcium from ____________
Extracellular space; Intracellular stores
72
The short period during ventricular systole when the ventricles are completely
closed chambers
Isovolumetric contraction
73
Heart failure due to a relatively mild blow to the chest
Commotio cordis
74
Negative chronotropic factors are factors that ______ heart rate
Decrease
75
The enlarged coronary vessel outside the heart that empties blood into the right atrium is the __________
Coronary sinus
76
In the fetal heart there is a ________ that allows blood to flow from the right atrium directly to the left atrium.
Foramen ovale
77
The ________ cells of the heart do not maintain stable resting membrane potentials; therefore, they continually depolarize.
Autorhythmic
78
Specialized conductive cells of the ventricles are called ________
Purkinje fibers
79
The ECG T wave interval represents ________
Ventricular repolarization
80
Cardiac output equals __________________
Heart rate * stroke volume
81
The ________ of the serous pericardium membrane covers the heart.
Visceral layer
82
The ________ valve of the heart has 3 valves with chordae tendineae.
Tricuspid
83
The ________ and ________ valves of the heart have no chordae tendineae attached
Aortic; pulmonary
84
Contraction of the muscle
Systole
85
Relaxation of the muscle
Diastole
86
The contraction
and relaxation of the ________ are normally described with the terms systole and
diastol
Ventricles
87
Pulmonary circuit pump
Right atrium to right ventricle to pulmonary arteries to lungs
88
Systemic circuit pump
Pulmonary veins to left atrium to left ventricle to aorta to body tissues to venae cavae
89
2 important functions of the cardiac conduction system
To initiate and distribute impulses throughout the heart
90
Why is oxygen so much more critical to the heart muscle than to skeletal muscles?
Cardiac muscle cells are highly dependent on oxygen and aerobic respiration, opposed to skeletal muscle cells. When forced to switch to anaerobic respiration, lactic
acid and rising H+ levels impair heart function.
91
What is the functional importance of the intercalated discs of cardiac muscle?
Intercalated disks contain anchoring desmosomes that prevent cell separation, and gap junctions that allow ions to travel from cell to cell
92
What is the
| functional importance of the fibrous skeleton of the heart?
The fibrous skeleton is connective
| tissue that reinforces the myocardium internally
93
The slowing the heart rate below 60 beats per minute
Bradycardia
94
Why is fibrosis of the cardiac muscle serious?
As the heart muscle stiffens it is unable to fill the atria as it once did, therefore less blood
is pumped. Further, as the muscle stiffens it takes more energy to expel the bolus of
blood from the heart which will eventually weaken the heart
95
Would an ECG with an inverted QRS wave be of concern to the doctor?
Not normally. What has probably happened is the technician has reversed the polarity on the leads causing the inverted wave
96
A 14-year-old girl undergoing a physical examination prior to being admitted to summer
camp was found to have a loud heart diastolic murmur at the second intercostal space to the
left side of the sternum. Explain the reason for the loud heart murmur associated with this girlʹs condition.
The heart murmur is due to incomplete closing of the pulmonary valve
97
A man enters the hospital complaining of chest pain. His history includes smoking, a stressful job, a diet heavy in saturated fats, lack of exercise, and high blood pressure. Although he is not suffering from a heart attack, his doctor explains to him that a heart attack is quite possible.
What did the chest pain indicate? Why is this man a prime candidate for a heart attack?
His symptoms indicate angina pectoris, possibly due to either atherosclerosis or
stress-induced spasms of the coronary arteries. If the arteries are occluded
(atherosclerosis), the heart muscle could be deprived of blood, and therefore oxygen. A
heart attack could occur if the coronary vessels experience further (or progressive)
occlusion.
98
An older woman complains of shortness of breath and intermittent fainting spells. Her doctor runs various tests and finds that the AV node is not functioning properly. What is the suggested treatment?
The suggested treatment is surgery to implant an artificial pacemaker.
99
An angiocardiogram was performed on an infant and it was found that he had a patent ductus arteriosus. Discuss the location and function of the ductus arteriosus in the fetus and relate it to the reason for the boyʹs breathlessness.
The ductus arteriosus is a shunt between the pulmonary trunk and the aorta in the
fetus, which normally closes at birth. Pathology is due to the mixing of oxygenated and
deoxygenated blood because the connection between the aorta and the pulmonary
trunk remains slightly open
100
A patient takes a nitroglycerin tablet sublingual for chest pain. Nitroglycerin acts directly on
smooth muscle, producing relaxation and vessel dilation. How would this relieve chest pain?
Angina pectoris is thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium, with resulting decreased oxygen being delivered to the cells. Because
nitroglycerin acts as a vasodilator, blood flow is increased, promoting the delivery of oxygen to the cells.
101
A patient was admitted to the hospital with chest pains. On admission, his pulse was 110 and blood pressure was 96/64. According to his history, his normal pulse rate is usually between 80 and 88 and his blood pressure runs from 120/70 - 130/80. Explain why these changes in BP and HR occur
Increased heart rate (measured by taking his pulse) without maintaining his normal blood pressure is suggestive of reduced stroke volume. Both a drop in blood volume and a weakened heart could cause this, but the chest pains suggest heart damage.
Failure of compensating mechanisms to maintain blood pressure suggest a serious decline in cardiac output.
102
A 55-year-old male was admitted to the hospital with heart failure. He complains of
increasing shortness of breath on exertion and needing to sleep on three pillows at night. On physical assessment, the nurse determines that his ankles and feet are very swollen. Which of these symptoms reflect left-sided heart failure and which reflect right-sided heart failure?
Because the heart is a double pump, each side can initially fail independently of the
other. If the left side fails, pulmonary congestion occurs. The right side of the heart continues to propel blood to the lungs, but the left side does not adequately eject the returning blood into the systemic circulation. Thus, blood vessels in the lungs become engorged with blood, pressure within them increases, and fluid leaks from the circulation into the lung tissue, causing pulmonary edema.
If the right side of the heart fails, peripheral congestion occurs. Blood stagnates within
body organs, and pooled fluids in the tissue spaces impair the ability of body cells to
obtain adequate nutrients and oxygen and to rid themselves of wastes. Edema is most
noticeable in the extremities (feet, ankles, and fingers).
103
Asystole is the total absence of ventricular electrical activity. Explain why defibrillation would
not be effective in this situation.
Defibrillation is accomplished by electrically shocking the heart which interrupts its
chaotic twitching by depolarizing the entire myocardium. In this case, the ventricles are at a total standstill and defibrillation would not be effective.
104
A patient is prescribed a calcium channel blocker to prevent angina (chest pain), by decreasing the demand for oxygen. Explain why.
By preventing the influx of calcium ions into myocardial and vascular smooth muscle cells, calcium channel blockers inhibit the intracellular release of additional stores of calcium ions. A drug that inhibits the release of intracellular calcium ions decreases the force of myocardial contractility, thereby decreasing the oxygen demand.
