Lesson 7 - The Circulatory System: Heart Flashcards
1
Q
cardiology
A
study of the heart and its disorders
2
Q
cardiovascular system
A
consists of heart and blood vessels
3
Q
the _____ is a pump that keeps blood flowing through vessels
A
heart
4
Q
_____ deliver blood to body tissues and returns it to the heart
A
vessels
5
Q
these are blood vessels that carry blood AWAY from the heart
A
arteries
6
Q
these are vessels that carry blood TOWARDS the heart
A
veins
7
Q
microscopic vessels that connect the smallest arteries to the smallest veins are called
A
capillaries
8
Q
circulatory system refers to (3)
A
the heart, vessels, and blood
9
Q
pulmonary circuit
A
carries blood to the lungs for gas exchange and back to the heart
10
Q
pulmonary circulation is performed by which side of the heart?
A
the right
11
Q
systemic circuit
A
supplies oxygenated blood to all tissues of the body and returns it to the heart
12
Q
systemic circulation is performed by what side of the heart?
A
the left
13
Q
pulmonary circuit: blood is sent to _____ of the lungs via the _____ _____, and _____ _____, where it picks up oxygen and returns to the heart via _____ _____
A
alveoli, pulmonary trunk, pulmonary arteries, pulmonary veins
14
Q
deoxygenated blood returns to the heart via… (2)
A
the inferior and superior vena cava
15
Q
the major arteries and veins entering and leaving the heart are called _____ _____
A
great vessels
16
Q
oxygenated blood is sent to the body via the _____
A
aorta
17
Q
the heart is located in the …..
A
mediastinum
18
Q
mediastinum
A
the space between lungs
19
Q
shape of the heart: base
what attaches here?
A
wide, SUPERIOR portion of the heart, large vessels attach here
20
Q
shape of the heart: apex
A
tapered INFERIOR end, tilts to the left
21
Q
at any age, the heart is the size of…
A
the fist
22
Q
the heart is enclosed by the _____
A
pericardium
23
Q
pericaridum
A
a double-walled sac surrounding the heart
24
Q
functions of the pericardium (4)
A
- allows heart to beat without friction
-provides room for expansion - resists excessive expansion
- anchored to diaphragm and sternum for support
25
fibrous pericardium
outermost layer of the pericardium
- a tough, fibrous sac
26
serous pericardium is comprised of... (2)
parietal layer and visceral layer
27
serous pericardium: parietal layer
lines the fibrous pericaridum
28
serous pericardium: visceral layer
aka epicardium
- adheres to the heart surface and outmost layer of the heart itself
29
pericardial cavity
the space between the parietal and visceral layers of the serous pericardium
30
the pericardial cavity is filled with...
pericardial fluid
31
pericarditis
inflammation of the pericardium, my result in friction rub
32
the heart wall consists of three layers
1. epicardium
2. myocardium
3. endocardium
33
the epicardium is also the...
visceral layer of the serous pericardium
34
epicardium (2)
- serous membrane covering the heart
- there is sometimes adipose tissue in a thick layer on portions of this
35
coronary blood vessels travel through what layer of the heart?
epicardium
36
endocardium
smooth inner lining of the heart and blood vessels
37
this layer of the heart covers the valve surfaces and is continuous with the endothelium of blood vessels
endocardium
38
myocardium
layer of cardiac muscle
39
thickness of the myocardium is _____ to workload
proportional
40
vortex of the heart
the muscle spiral around the heart that produces a wringing motion during contraction
41
fibrous skeleton
framework of collagenous and elastic fibers in the heart
42
fibrous rings
part of the fibrous skeleton that provides structural support and attachment for cardiac muscle and anchors for valve tissue
43
what important thing does the fibrous skeleton supply for the heart?
electrical insulation between the atria and ventricles which is important in timing and coordination of contractile activity
44
auricle
an earlike flap that increases the chamber volume of the atria
45
interatrial septum
a wall between the atria of the heart
46
which ventral wall is bigger? left or right? why?
left, it pumps blood to the body and not just the lungs so it needs to be stronger to cover the distance
47
boundaries of the chambers of the heart are marked by....
sulci, grooves
48
coronary sulcus
separates atria above from ventricles below, encircles the heart near the base
49
anterior and posterior interventricular sulci
separate the left and right ventricles; overlie the interventricular septum and extend obliquely down heart, from base and apex
50
cusps/leaflets
the fibrous flaps of the atrioventricular valves
51
atrioventricular valves control...
blood flow between the atria and ventricles
52
what is another name for the right atrioventricular valve?
tricuspid
53
what is another name for the left atrioventricular valve?
bicuspid
54
tendinous cords are also called
chordae tendineae
55
chordae tendineae
strings of connective tissue that attach valve cusps to papillary muscles on the floor of ventricles
56
what is the purpose of chordae tendineae?
they prevent the AV valves from flipping or bulging into atria when ventricles contract
57
semilunar valves control...
flow from the ventricles into great arteries
58
pulmonary semilunar valve
controls the opening between the right ventricle and pulmonary trunk
59
aortic semilunar valve
controls the opening between the left ventricle and aorta
60
how many cusps do the semilunar valves have?
three each
61
when are cusps of the semilunar valves pressed up against arterial walls?
during ventricular contraction and blood ejection
62
when are the semilunar valves closed?
when the ventricles relax, and blood flows back towards them and fills
63
pathway of blood: steps 1-3
1. blood enters the right atrium from the superior/inferior venae cavae
2. blood in the right atrium flows through the right AV valve into the right ventricle
3. contraction of the right ventricle forces the pulmonary semilunar valve open
64
pathway of blood: steps 4-6
4. blood flows through pulmonary semilunar lavle into the pulmonary trunk
5. blood is distributed by the right and left pulmonary arteries into the lungs, where it unloads CO2 and loads O2
6. blood returns from lungs via the pulmonary veins to the left atrium
65
pathway of blood: steps 7-9
7. blood in the left atrium flows through the left AV valve into the left ventricle
8. contraction of the left ventricle (simultaneous with step 3) forces the aortic valve open
9. blood flows through the aortic valve into the ascending aorta
66
pathway of blood: steps 10 and 11
10. blood in the aorta is distributed to every organ in the body, where it unloads O2 and loads CO2
11. blood returns to the right atrium via venae cavae
67
coronary circulation
the heart's own supply of vessels to deliver blood to the myocardium
68
left coronary artery branches off from where?
the ascending aorta
69
the left anterior descending branch of the left coronary artery is also known as...
| ai
the anterior interventricular branch
70
the anterior interventricular branch supplies blood where?
to both ventricles and anterior two-thirds of the interventricular septum
71
what does the left coronary artery branch into? (2)
| a.c.
- anterior interventricular branch
- circumflex branch
72
where is the circumflex branch of the coronary circuit?
passes around the left side of the heart in the coronary sulcus
73
where does the circumflex branch of the coronary circuit end?
the posterior side of the heart
74
the circumflex branch of the coronary circuit branches what other artery?
the left marginal branch
75
where does the right coronary artery branch off of?
the ascending aorta
76
the right coronary artery branches into... (2)
| r.p.
- right marginal branch
- posterior interventricular branch
77
where does the right marginal branch supply the coronary circuit?
| l
the lateral aspect of the right atrium and ventricle
78
where does the posterior interventricular branch of the coronary circuit supply?
the posterior walls of both ventricles and the interventricular septum
79
flow through the coronary arteries is the greatest when the heart _____
relaxes
80
what happens to the coronary arteries during ventricular contraction? (2)
they compress, the open aortic valve blocks blood flow into them
81
what happens to the coronary arteries during relaxation?
blood in the aorta surges back toward the heart and into the openings of the coronary arteries
82
angina pectoris
chest pain from partial obstruction of coronary blood flow
83
chest pain is caused by...
ischemia of cardiac muscles
84
explain how heart pain occurs
obstruction of coronary blood flow causes the myocardium to shift to anaerobic fermentation, producing lactate and stimulating pain
85
myocardial infarction
heart attack
- sudden death of a patch of myocardium resulting from long-term obstruction of coronary circulation
86
atheroma
blood clot/fatty deposit
87
what happens to cardiac muscles downstream of an atheroma?
they die due to lack of circlation
88
what often obstructs coronary arteries?
atheromas
89
how can you tell if someone is having a heart attack?
they have heavy pressure or squeezing pain radiating into the left arm
90
some painless heart attacks may disrupt _____ _____ pathways leading to fibrillation and cardiac arrest
electrical conduction
91
venus drainage
route by which blood leaves an organ
92
5-10% of coronary blood drains directly into heart chambers by way of _____ _____ _____
small cardiac veins
93
most coronary blood returns to the right atrium via these four veins
| g.pi.lm.c.
1. great cardiac vein
2. posterior interventricular (middle cardiac) vein
3. left marginal vein
4. coronary sinus
| the first three merge into the conorary sinus
94
the great cardiac vein drains blood from what portion of the heart?
anterior aspect
95
the posterior interventricular (middle cardiac) vein drains blood from what portion of the heart?
posterior aspect
96
the left marginal vein drains blood from what portion of the heart?
| a->lm
apex up the left margin
97
the coronary sinus drains blood from what portion of the heart?
receives blood from the left marginal, middle cardiac, and great cardiac veins and empties into the right atrium
98
the heartbeat is myogenic meaning...
signals original in the heart itself
99
the heart is autorhythmic, meaning...
it has a built in pacemaker and electrical system so it does not rely on the nervous system for its rhythm
100
cardiomyocyte features (4)
- striated, short, thick, BRANCHED muscle
- ONE central nucleus surrounded by glycogen
- SR lacks terminal cisterns
- large T tubules
101
intercalated discs
connections between cardiomyocytes
102
intercalated discs contain... (3)
interdigitating folds, mechanical junctions, and electrical junctions
103
interdigitating folds
membranes of cells folded to lock cells together and increase surface of contact
104
desmosomes
mechanical junctions of intercalated discs
- mechanical linkages that prevent contracting cardiomyocytes from being pulled apart
105
gap junctions
electrical junctions in intercalated discs
- allow ions to flow between cells, and they stimulate their neighbors and contract in unison
106
cardiac muscle depends almost exclusively on what to make ATP?
aerobic respiration
107
what adaptations help cardiac muscle to depend on aerobic respiration? (3)
- rich in myoglobin and glycogen
- hugh mitochondria
- hardly uses anaerobic fermentation or O2 debt mechanisms
108
cardiac muscle is adaptable to different organic fuels including... (5)
fatty acids (60%), glucose (35%), ketones, lactate, and amino acids (5%)
109
the heart is more vulnerable to _____ _____ than lack of a _____ _____
O2 deficiency, specific fuel
110
cardiac conduction system (2)
| what does it do? what does it consist of?
- coordinates the heartbeat
- consists of an internal pacemaker and nerve-like conduction pathways through the myocardium
111
cardiac conduction system pathway (5)
1. SA node fires
2. signals spread through atria
3. AV node fires
4. AV bundle carries signal through the interventricular septum
112
sinoatrial (SA) node
patch of modified cardiomyocytes in the right atrium that serve as the pacemaker that initiates each heartbeat
113
what initiates heartbeats and determines heart rate?
the SA node
114
atrioventricular (AV) node
patch of modified cardiomyocytes that serve as an electrical gateway to the ventricles
115
what prevents electrical signals from passing to the ventricles?
the fibrous skeleton, the AV node is the only way to receive electrical signals
116
atrioventricular (AV) bundle
pathway from which signals leave the AV node
117
the AV bundle forks into..
the right and left bundle branches
118
subendocardial branches
Purkinje fibers
- processes arising from lower end of bundle branches that extensively branch through the ventricular myocardium
119
where do the AV bundle branches travel?
the interventricular septum
120
once signals reach the end of the conduction system, they are perpetuated by...
cardiomyocytes via gap junctions
121
systole
heart contraction
122
diastole
heart relaxation
123
blood pressure is read as...
systolic pressure/diastolic pressure
124
sinus rhythm
normal heartbeat triggered by the SA node
125
ectopic focus
a region of spontaneous firing other than the SA node
126
what may govern the heart rhythm if the SA node is damaged?
an ectopic focus
127
nodal (junctional) rhythm
if the SA node is damaged, heart rate is set by the AV node (40-50 bpm vs. 70-80bpm)
128
does the SA node have a stable resting membrane potential?
no it does not
129
describe the resting membrane potential of the SA node (3)
1. it starts at -60mV and drifts upwards
2. when it reaches -40mV, channels open causing faster depolarization to 0mV
3. repolarization occurs, and the pacemaker potential starts over again
130
pacemaker potential/prepotential
the gradual depolarization of the SA node due to a slow influx of Na+
131
what causes the faster depolarization that occurs from -40mV to 0mV?
at -40mV, voltage-gated channels for Ca2+ and Na+ open allowing them to enter the cells
132
how does repolarization of the SA node occur?
when membrane potential reaches 0mV, K+ channels open and causes the ion to leave the cell, restarting the process
133
when the SA node fires, it sets off the ______
heartbeat
134
signal from the SA node stimulates the _____ to contract almost simultaneously
artia
135
signal from the SA node reaches the AV in..
50 ms
136
why do signals slow down through the AV node?
due to thin cardiomyocytes with fewer gap junctions
137
why is it important that signals from the AV node are slowed down before reaching the ventricles?
it allows them more time to fill with blood
138
after the AV node, how do signals travel through the AV bundle and Purkinje fibers?
it moves very quickly, and causes the ventricles to contract in near unison
139
ventricular systole progresses from..
the apex of the heart
140
cardiomyocytes have a stable resting potential of...
-90mV
141
cardiomyocyte action potential: depolarization
stimulus opens voltage-gated Na+ channels, where it peaks at +30mV
142
cardiomyocyte action potential: when do sodium channels inactivate?
at +30mV
143
cardiomyocyte action potential: plateau
| specific process
voltage-gated slow Ca2+ channels open allowing Ca2+ to enter the cell which triggers opening of the Ca2+ channels on the SR, flooding the cytosol with calcium
144
cardiomyocyte action potential: why is the plateau phase important?
it sustains contraction for expulsion of blood from the heart
145
cardiomyocyte action potential: repolarization
Ca2+ channels close, K+ channels open allowing K+ to enter quickly and repolarize the cell to its resting potential
146
cardiac muscles have a long...
absolute refractory period
147
why is the long absolute refractory period of cardiac muscle important?
it prevents wave summation and tetanus, which would stop the pumping action of the heart
148
interpretation of the electrocardiogram: P wave
atrial depolarization
149
interpretation of the electrocardiogram: QRS complex
ventricular depolarization
150
interpretation of the electrocardiogram: T wave
| prior to...
ventricular repolarization immediately PRIOR to diastole
151
interpretation of the electrocardiogram: PR interval
| a->v
signal conduction through the AV node before activating the ventricles
152
interpretation of the electrocardiogram: QT interval
duration of ventricular depolarization
153
when is the QT interval shorter?
during exercise
154
interpretation of the electrocardiogram: QRS interval
| not ventricular depolarization
atrial repolarization and diastole
155
why can't you read atrial repolarization on the electrocardiogram?
it is concealed by the QRS wave
156
interpretation of the electrocardiogram: PQ segment
| S->A
signal conduction from the SA to AV nodes, atrial systole begins
157
interpretation of the electrocardiogram: ST segment
ventricular systole and ejection of blood
158
the ST segment corresponds to what?
the plateau of cardiomyocytes' action potentials
159
deviations of an ECG can indicate... (4)
| m.a.h.e.
- myocardial infarction
- abnormalities in conduction pathways
- heart enlargement
- electrolyte and hormone imbalances
160
deviations of an ECG: ventricular fibrillation (Vfib)
random electrical signals result in no pumping action; hallmark of a heart attack and quickly fatal
161
deviations of an ECG: atrial fibrillation (Afib)
weak rippling contraction in the atria due to chaotic signals, the atria fail to stimulate ventricles
162
what is the most common atrial arrhythmia in elderly individuals?
atrial fibrillation
163
is Afib or Vfib not immediately fatal?
Afib
164
deviations of an ECG: heart block
failure of part of the conduction system
- includes bundle branch block and total heart block
165
deviations of an ECG: total heart block
| a
AV node failure, 20-40 bpm heartrate
166
what heart arrhythmia is this?
premature ventricular contraction
167
what heart arrhythmia is this?
heart block
168
what heart arrhythmia is this?
atrial fibrillation
169
what heart arrhythmia is this?
ventricular firbillation
170
what heart arrhythmia is this?
trick question - this is sinus (normal) rhythm
171
