Chapter 18 (Lecture) - Heart Flashcards
1
Q
when the mitral valve closes, it prevents backflow from the
A
left ventricle into the left atrium
2
Q
what is the purpose of the chordae tendineae
A
anchor the AV valves in the closed position
3
Q
what makes the heart valves open and close?
A
blood pressure
4
Q
what valve separates the left atrium and left ventricle
A
bicuspid (mitral) valve
5
Q
valve between the right atrium and right ventricle
A
tricuspid valve
6
Q
prevents backflow of blood into the left ventricle
A
aortic semilunar valve
7
Q
where does the blood leave from the left atrium
A
mitral (bicuspid) valve
8
Q
a condition in which the valve flaps of the heart becomes stiff and consticts the opening
A
stenosis
9
Q
separates the left ventricle and the aorta
A
aortic semilunar valve
10
Q
separates the right ventricle and the pulmonary trunk
A
pulmonary semilunar valve
11
Q
separates the right atrium from the right ventricle
A
tricuspid valve
12
Q
where does blood leave from the left ventricle
A
aortic semilunar valve
13
Q
prevents backflow of blood into the right ventricle
A
pulmonary semilunar valve
14
Q
attached to the AV valve flaps
A
chordae tendineae
15
Q
where does the blood leave from the right ventricle
A
pulmonary semilunar valve
16
Q
what prevents the atrioventricular valves from everting during ventricular contraction
A
papillary muscles
17
Q
which valve is most often faulty in the heart
A
mitral (bicuspid) valve
18
Q
where does the blood leave from the right atrium
A
tricuspid valve
19
Q
failure of which heart valve would allow blood to move from the left ventricle to the left atrium
A
mitral (bicuspid) valve
20
Q
the right side of the heart pumps blood through which circuit
A
pulmonary
21
Q
- the left side of the heart pumps blood through which circuit
- associated with the left ventricle
- long pathway throughout the entire body and encounters about 5x as much friction, or resistance to blood flow
A
systemic circuit
22
Q
the right side of the heart receives what type of blood from where
A
oxygen-poor blood from body tissues
23
Q
the left side of the heart receives what type of blood from where
A
oxygen-rich blood from the lungs
pumps blood to supply oxygen and nutrients to body tissues
24
Q
- blood vessels that carry blood to and from the lungs
- served by the right ventricle
- short, low pressure circulation
A
pulmonary circuit
25
the blood vessels that carry blood to and from all body tissues
systemic circuit
26
receives blood returning from the systemic circuit
right atrium
27
receives blood returning from the pulmonary circuit
left atrium
28
* pumps blood INTO the pulmonary circuit
* forms most of the anterior surface of the heart
right ventricle
29
* pumps blood INTO the systemic circuit
* dominates the inferoposterior aspect of the heart and forms the apex
left ventricle
30
the medial cavity of the thorax containing the heart, great vessels, thymus and parts of the trachea, bronchi, and esophagus
mediastinum
31
posterior surface of the heart that is directed toward the right shoulder
base
32
inferiorly pointed part of the heart that points toward the left hip
apex
33
double-layered sac enclosing the heart and forming its superficial layer; has fibrous and serous layers
pericardium
34
* loosely fitting part of the pericardium
* made up of tough, dense CT
* functions to: protect the heart, anchors the heart to surrounding structures, and prevents the overfilling of the heart with blood
fibrous pericardium
35
* deep to the fibrous pericardium
* a thin, slippery, two-layer serous membrane that forms a closed sac around the heart
serous pericardium
36
* lines the internal surface of the fibrous pericardium
* attaches to the large arteries exiting the heart and continues over the external heart surface as the visceral layer (epicardium)
parietal layer of pericardium
37
* located between the parietal and visceral layers of the pericardium
* contains a film of serous fluid
pericardial cavity
38
* inflammation of the pericardium
* roughens surface membrane surfaces
pericarditis
39
* the visceral layer of the serous pericardium
* most superficial layer of the heart wall
* often infiltrated with fat, especially in older people
epicardium
40
* composed mainly of cardiac muscle and forms the bulk of the heart
* the layer of the heart that contracts
* contains CT fibers arranged in circular bundles that link all parts of the heart together
myocardium
41
CT fibers in the myocardium that reinforce it internally and anchors the cardiac muscle fibers
cardiac skeleton
42
* the innermost layer of the heart
* a glistening white sheet of endothelim (squamous epithelium) resting on a thin CT layer
* located on the inner myocardial surface and lines heart changers and covers the fibrous skeleton of the valves
endocardium
43
the internal partition that divides the heart longitudinally and separates the atria
interatrial septum
44
the internal partition that divides the heart longitudinally and separates the ventricles
interventricular septum
45
* also known as the atrioventricular groove
* encircles the junction of the atria and ventricles like a crown
coronary sulcus
46
* cradles the anteriorventricular artery (LAD)
* marks the anterior position of the septum separating the right and left ventricles
* continues as PI sulcus
anterior interventricular sinus
47
the right ventricle pumps blood into ... which routes blood to the lungs where gas exchange occurs
pulmonary trunk
48
the largest artery in the body
aorta
49
returns blood from body regions superior to the diaphragm
superior vena cava
50
returns blood from body areas below the diaphragm
inferior vena cava
51
collects blood draining from the myocardium
coronary sinus
52
irregular ridges of muscle that mark the internal walls of the ventricular chambers
trabeculae carneae
53
muscle bundles that project into the ventricular cavity and play a role in valve function
papillary muscles
54
landmarks the posterior position of the septum that separates the left and right ventricles
posterior interventricular sulcus
55
* located in the interatrial septum, faces the right atrium
* marks the location of the fetal foramen ovale in the heart
fossa ovalis
56
small, wrinkled, protruding appendages which increase the atrial volume somewhat
auricles
57
* located the anterior portion of the right atrium and in the auricle of the left atrium
* look like the teeth of a comb
pectinate muscles
58
a C-shaped ridge that separates the posterior and anterior regions of the right atrium
crista terminalis
59
tributaries of the coronary sinus
* great cardiac vein
* small cardiac vein
* middle cardiac vein
60
several of these empty directly into the right atrium anteriorly
anterior cardiac veins
61
* empties the blood into the right atrium
* cardiac veins form this
coronary sinus
62
after passing through the capillary beds of the myocardium, the venous blood is collected by
cardiac veins
63
artery that courses to the right side of the heart
right coronary artery
64
two branches of the right coronary artery
* right marginal artery
* posterior interventricular artery (posterior inferior descending artery)
65
artery that serves the myocardium of the lateral right side of the heart
right marginal artery
66
* runs to the heart apex and supplies the posterior ventricular walls
* near the apex of the heart, this artery merges (anastomoses) with the anterior interventricular artery (LAD)
posterior interventricular artery
## Footnote
otherwise known as the posterior inferior descending artery
67
* runs toward the left side of the heart
* branches into the anterior interventricular artery (LAD) and circumflex artery
left coronary artery
68
* known clinically as the left anterior descending artery
* follows the anterior interventricular sulcus and supplies blood to the interventricular septum and anterior walls of both ventricles
anterior interventricular artery
69
supplies the left atrium and the posterior wals of the left ventricle
circumflex artery
70
which ventricle generates more pressure
left ventricle
71
the functional blood supply of the heart and the shortest circulation in the body
coronary circulation
72
* located at each atrial-ventricular junction
* prevent backflow into the atria when the ventricles contract
atrioventricular (AV) valves
73
* attached to each AV flap
* tiny white collagen chords that anchor the cusps to the papillary muscles protruding from the ventricular walls
* also known as the heart strings
chordae tendineae
74
act as tethers that anchor the valve flaps in their closed position
chordae tendineae and papillary muscles
75
* guard the bases of the large arteries issuing from the ventricles and prevent backflow into the associated ventricles
* crescent moon cusp shaped
aortic and pulmonary semilunar (SL) valves
76
* arise from the base of the aorta and encircle the ehart in the coronary sulcus
* provide arterial supply of coronary circulation
left and right coronary arteries
77
the act of listening to the heart with a stethoscope
auscultating
78
what is happening during the "pause" phase when the heart is resting/relaxing?
the ventricles are filling
79
what causes the abnormal swishing or whooshing sound that is heard as blood regurgitates back into an atrium from its associated ventricle
blood turbulence
80
which chamber of the heart has the highest probability of being the site of a myocardial infarction (MI)
left ventricle
81
the presence of an incompetent tricuspid valve would have the direct effect of causing
reduced efficiency in the delivery of blood to the lungs
## Footnote
The tricuspid valve separates the right atrium and the right ventricle. It must remain tightly closed during ventricular contraction so blood can be pumped out of the ventricle and into the pulmonary arteries.
82
if the mitral valve is unable to close properly,
blood could flow back into the left atrium
83
Failure in a particular structure of the heart tends to cause a backup of blood in the lungs, known as pulmonary congestive heart failure. Failure of which structure of the heart would lead to such a backup?
left ventricle
## Footnote
Failure in the left ventricle can cause increased blood hydrostatic pressure in the lungs, causing fluid buildup in the alveoli.
84
the left ventricular wall of the heart is thicker than the right wall in order to
pump blood w/ greater pressure
85
the source of blood carried to the capillaries in the myocardium
coronary arteries
86
what separates the parietal and visceral pericardium
pericardial cavity
87
excessive amount of fluid in the pericardial cavity
prevents the heart from filling properly with blood
88
# true or false:
the left side of the heart pumps the same volume of blood as the right
true
89
lines the internal surface of the fibrous pericardium
parietal pericardium
90
# true or false:
the role of the chordae tendineae is to open the AV valves at the appropriate time
false
## Footnote
Chordae tendineae anchor the cusps of the AV valves to the papillary muscles protruding from the ventricular walls. The chordae tendineae and the papillary muscles act as tethers that anchor the valve cusps in their closed position. If the cusps were not anchored, they would be blown upward (everted) into the atria, in the same way an umbrella is blown inside out by a gusty wind. The papillary muscles contract with the other ventricular musculature so that they take up the slack on the chordae tendineae as the full force of ventricular contraction hurls the blood against the AV valve cusps.
91
heart sounds are caused by
heart valve closure
92
what receives blood during ventricular systole
both the aorta and pulmonary trunk
93
the AV valves are closed when
the ventricles are in systole
94
during the period of ventricular filling,
blood flows mostly passively from the atria through the atrioventricular (AV) valves into the ventricles
95
what BP is necessary to force blood through vessels and effect cellular exchange of gases, wastes, and nutrients
120/80
96
what is responsible for the Lub sound
closure of the AV valves
97
what is responsible for the Dup sounds
closure of the semilunar valves
98
what does the QRS wave of the ECG represent
ventricular depolarization
99
cardiac temponade results in ineffective pumping of blood by the heart; because the excessive amount of fluid in the pericardial cavity will
prevent the heart from filling properly with blood
100
why are gap junctions a vital part of the intercellular connection of cardiac muscles?
gap junctions allow action potentials to spread to connected cells
## Footnote
Gap junctions are a form of electrical synapse that allow action potentials to spread to connected cells. This property allows the signal to spread efficiently through the heart.
101
pathway of the stimulation through the heart
1. AV node
2. AV bundle
3. interventricular septum
4. subendocardial conducting network
102
Suppose a patient develops a myocardial infarction that disables the sinoatrial node. Would the heart still pump blood to the aorta and the pulmonary trunk?
Yes, because the atrioventricular node will still stimulate ventricular systole.
## Footnote
The atrioventricular node spontaneously depolarizes similarly to the sinoatrial node, but more slowly. It can lead to the ventricles pumping blood to the aorta and pulmonary trunk around 50 times per minute.
103
Which portion of the electrocardiogram represents the wave-like change in charge in the positive direction received by the atria from the sinoatrial (SA) node?
p wave
## Footnote
The P wave represents the depolarization of the left and right atria and the beginning of atrial systole
104
Which portion of the ECG cycle overlaps with the expected ventricular contraction (or systole)?
Q-T interval
## Footnote
The Q-T interval is the period from the beginning of ventricular depolarization through ventricular repolarization, during which the ventricles are in systole.
105
The plateau phase of an action potential in cardiac muscle cells is due to the
influx of Ca2+ through slow Ca2+ channels
106
# true or false:
an ECG provides direct information about valve function
false
107
at what point in the cardiac cycle is pressure in the ventricles the highest (around 120 mm Hg in the left ventricle)
ventricular systole
108
what causes heart sounds
heart valve closure
109
which part of the heart receives blood during ventricular systole
both the aorta and pulmonary trunk
110
the AV valves are closed when
the ventricles are in systole
111
refers to the short period during ventricular systole when the ventricles are completely closed chambers
isovolumetric contraction
112
As your skeletal muscles contract during physical activity, more blood is returned to the heart. Which variable would be affected and what would be the outcome of this action?
Preload would be increased, which would result in a larger cardiac output.
## Footnote
More blood returning to the heart would increase the volume of blood in the ventricles at the end of their filling phase (called end diastolic volume, or EDV). A larger EDV results in greater stretching of the myocardium, or a greater preload. Stretching (lengthening) the contractile cells brings them closer to their optimal length, allowing them to produce more force when stimulated to contract. The stronger contraction results in a larger stroke volume, and therefore a larger cardiac output.
113
# true or false:
increasing end-diastolic volume (EDV) and end-systolic volume (ESV) will increase stroke volume
false
## Footnote
Stroke volume (the volume of blood ejected from the ventricle during systole) is equal to the difference between EDV (the volume of blood in the ventricle before it contracts) and ESV (the volume of blood remaining in the ventricle after it contracts). Increasing EDV will result in a larger stroke volume; however, increasing ESV will result in a smaller stroke volume.
114
hypercalcemia could cause
prolonged T wave
## Footnote
The T wave on an ECG tracing represents ventricular repolarization. Repolarization requires the net efflux of K+ ions. Recall that changes in normal concentrations of ions (like Ca2+) in the plasma can affect the ability of other ions to move in and out of the cell.
115
which cranial nerve carries efferent parasympathetic motor impulses to the heart and other major organs
vagus nerve
116
which part of the intrinsic conduction system is slowed by impulses from the vagus nerve
SA node
117
Which term describes an area of the heart conduction system where the impulse is delayed for 0.1 sec?
AV node
118
Which of the following factors gives the myocardium its high resistance to fatigue?
Large number of mitochondria in the cytoplasm
119
the cells of the myocardium behave as a single, coordinated unit called a
functional syncytium
120
the role of the atrioventricular node (AV node) is to
slow down impulses so that atria can contract to fill the adjacent ventricles with blood
121
the absolute refractory period refers to the time during which
the muscle cell is not in a position to respond to a stimulus of any strength
122
ventricular repolarization is indicated by which wave
T wave
123
the ability of some cardiac muscle cells to initiate their own depolarization and cause depolarization of the rest of the haert is called
automaticity
124
another term for contraction
systole
125
the area of the heart conduction system with the fastest depolarizing pacemaker cells
SA node
126
which wave signifies atrial depolarization
P wave
127
what is a difference between cardiac muscle and skeletal muscle
unlike skeletal muscle cells, cardiac muscle has gap junctions between cells that allow them to be autorhythmic
128
carries parasympathetic fibers to the sinoatrial (SA) node
vagus nerve (X)
129
signifies ventricular depolarization
QRS complex
130
sequence of current flow through the intrinsic conduction system of the heart
1. SA node
2. AV node
3. AV bundle
4. right and left bundle branches
5. subendocardial conducting network
131
the P wave of an ECG represents
atrial depolarization
132
Given an end diastolic volume (EDV) of 120 ml / beat and an end systolic volume (ESV) of 50 ml / beat, the stroke volume (SV) would be
70 ml / beat
133
# true or false:
if blood volume decreased dramatically due to massive bleeding, the autonomic nervous system will attempt to maintain cardiac output by increasing the heart rate.
true
134
# true or false:
when released in large quanities, thyroxine, a thyroid gland hormone, causes a sustained increase in heart rate
true
135
striated and uninuclear; short, and branched
cardiac muscle cells
136
* connects cardiac muscle cells
* special anchors that hold the cells together and allow them to communicate via gap junctions
intercalated discs
137
opening of fast sodium channels
rapid depolarization
138
plateau phase is when slow calcium channels open and prevent rapid repolarization
rapid partial repolarization
139
calcium channels shut and membrane is again most responsive to potassium
repolarization
140
steps to action potential generation in cardiac muscles
1. rapid depolarization
2. partial repolarization
3. repolarization
141
how long does it take for skeletal muscles to generate an action potential
2 milliseconds
142
how long does it take for cardiac muscle to generate an action potential
300-500 milliseconds
143
why is the refractory period of cardiac muscle action potential so prolonged
so that fatigue doesn't set in when the cardiac muscle beats
144
which hormones increase heart rate
* epinephrine
* norepinephrine
* thyroid hormone
145
what effect does parasympathetic innervation have on heart rate and cardiac output?
decreased heart rate and lower cardiac output
146
what effect does sympathetic innervation have on heart rate and cardiac output
increases heart rate and cardiac output, along with increased contractility
147
the degree of stretch in cardiac muscle fibers before they contract
preload
148
end diastolic volume - end systolic volume
stroke volume
149
cardiac output =
stroke volume x heart rate
150
increasing the stretch in the ventricles by increasing what will increase stroke volume
increasing venous return
151
nerves run to the heart muscle and to the SA and AV nodes to accelerate the heart
sympathetic innervation of the heart
152
travels to the heart mainly via the vagus nerve and impacts the SA and AV nodes
parasympathetic innervation of the heart
153
what prevents rapid depolarization
slow Ca2+ channels
154
what occurs before contraction
depolarization
155
which part of the intrinsic conduction system depolarizes the fastest
SA node
156
what ions are the main effectors of cardiac output
* calcium
* sodium
* potassium
157
if stroke volume increases and heart rate stays the same, then what happens to cardiac output?
cardiac output increases
158
the amount of blood pumped out by each ventricle per minute
cardiac output
159
sounds heard in the 2nd intercostal space at the right sternal margin
aortic valve
160
sounds heard in the 2nd intercostal space at the left sternal margin
pulmonary valve
161
sounds heard over heart apex (in 5th intercostal space) in line with the middle of the clavicle
mitral valve
162
sounds typically heard in right sternal margin of 5th intercostal space
tricuspid valve
163
diagram that ties electrical and mechanical events together
Wigger's diagram
164
steps to the cardiac cycle
1. ventricular filling (ventricular filling and atrial contraction)
2. ventricular systole (isovolumentric contraction --> ventricular ejection)
3. early diastole (isovolumetric relaxation)
165
measures the electrical activity in the heart
electrocardiography
166
atrial depolarization initiated by the SA node causes this wave
P wave
167
atrial depolarization is complete and the impulse is delayed at the AV node
PQ interval
168
* ventricular depolarization begins at apex, causing this wave
* atrial repolarization occurs
QRS complex
169
ventricular depolarization is complete
ST interval
170
ventricular repolarization begins at the apex, causing this wave
T wave
171
* SA node nonfuncitonal
* P waves are absent
* heart is paced by AV node at 40-60bpm
junctional rhythm
172
* some P waves are not conducted through the AV node
* more P than QRS waves seen
* ratio of P waves to QRS waves is mostly 2:1
second degree heart block
173
* the volume of blood pumped out by one ventricle with each beat
* correlates with the force of ventricular contraction
stroke volume
174
* the difference between resting and maximal CO
* in nonathletes is typically 20-25 L/min
cardiac reserve
175
the degree to which cardiac muscle cells are stretched just before they contract
preload
176
the higher the preload,
the higher the stroke volum
177
* the relationship between preload and stroke volume
* higher preload = higher stroke volume
Frank-Starling
178
* most important factor stretching cardiac muscle
* the amount of blood returning to the heart and distending its ventricles
venous return
179
resting fetal heart rate
140-160bpm
180
avg female resting heart rate
72-80bpm
181
male resting heart rate
64-72 bpm
182
* raises HR by acting through the sympathetic nervous system
* increases systemic blood pressure and routes more blood to working muscles
exercise
183
what happens when the right side of the heart fails
peripheral congestion
## Footnote
blood stagnates in body organs, and pooled fluids in the tissue spaces impair the ability of body cells to obtain adequate nutrients and oxygen and rid themselves of waste
edema in extremities
184
what are common treatments for damaged heart muscle
* removing excess leaked fluid w/ diuretics
* reducing afterload with drugs that drive down bp
* increasing contractility w/ digitalis derivatives
* heart transplants and other surgical remedies
185
* when the left side of the heart fails
* right side of the heart continues to propel blood to the lungs but the left side doesn't adequately eject the returning blood into systemic circulation
## Footnote
causes pulmonary edema due to engorged vessels w/ increased bp, and fluid leaks from vessels into lung tissue
pulmonary congestion
186
* ventricles stretch and become flabby and the myocardium deteriorates, often for unknown reasons
* drug toxicity and chronic inflammation may be involved
dilated cardiomyopathy (DCM)
187
* a succession of myocardial infarctions (heart attacks) depresses pumping efficiency because noncontractile fibrous (scar) tissue replaces the dead heart cells
multiple myocardial infarctions
188
* fatty buildup that clogs the coronary arteries, impairs blood and oxygen delivery to cardiac cells
* heart becomes increasingly hypoxic and begins to contract ineffectively
coronary athersclerosis
189
* the heart is such an inefficient pump that blood circulation is inadequate to meet tissue needs
* a progressively worsening disorder that reflects the weakening of the myocardium by various conditions that damage it in different ways
* common causes include: coronary atherosclerosis, persistent high bp. multiple MIs, dilated cardiomyopathy (DCM)
congestive heart failure (CHF)
190
* an abnormally fast resting heart rate (>100 bpm) that may result from elevated body temp, stress, certain drugs, or heart disease
* if persistent, considered pathological because it occasionally promotes fibrillation
tachycardia
191
* a resting heart rate slower than 60bpm
* may result from low body temperature, certain drugs, or parasympathetic NS activation
* often a warning of brain edema after head trauma
bradycardia
192
increases HR by enhancing the metabolic rate of cardiac cells
heat
193
* an autonomic reflex initiated by increased venous return and increased atrial filling
* stretching the atrial walls increases heart rate by stimulating both the SA node and the atrial stretch receptors, triggering reflexive adjustments of autonomic output to the SA node, increasing HR
atrial (Bainbridge) reflex
194
factors that increase heart rate
positive chronotropic factors
195
factors that decrease heart rate
negative chronotropic factors
196
exerts the most important extrinsic controls affecting heart rate
ANS
197
in what condition is afterload particularly important and why
hypertension; reduces ability of the ventricles to eject blood
198
* the pressure that ventricles must overcome to eject blood
* essentially the back pressure that arterial blood exerts on the aortic and pulmonary valves (~80 mmHg in the aorta and 10 mmHg in the pulmonary trunk)
afterload
199
200
the major intrinsic factor influencing stroke volume
end diastolic volume
201
* the contractile strength achieved at a given muscle length
* rises more when more Ca2+ enters the cytoplasm from the extracellular fluid and the SR
contractility
202
what is the effect of enhanced contractility
more blood is ejected from the heart (greater SV) and lower ESV
203
* substances that increase contractility
* epinephrine, thyroxine, glucagon, the drug digitalis, high levels of extracellular Ca2+
positive inotropic agents
204
* impair or decrease contractility
* induce acidosis
* include rising EC K+ levels and also calcium channel blockers
negative inotropic agents
