Heart Flashcards
(119 cards)
1
Q
Where can you find the heart in the human body?
A
superior to diaphragm, medial cavity of thorax, enclosed in mediastinum
2
Q
Where on the heart is the point of maximum intensity (where contractions are strongest)?
A
apex
3
Q
Why are contractions the strongest at the bottom of the heart?
A
to prevent blood from pooling
4
Q
What is the name of the membrane that covers the heart?
A
pericardium
5
Q
what are the two layers of the pericardium?
A
fibrous + serous
6
Q
What is the fibrous layer of the pericardium composed of?
A
protiens/fibers (e.g. collagen)
7
Q
Which layer of the pericardium is double layered and filled with fluid?
A
serous
8
Q
What is the name of the cavity where serous fluid is found?
A
pericardial cavity
9
Q
Which layer of the serous pericardium is closest to the heart?
A
visceral
10
Q
Which layer of the serous pericardium is farthest from the heart?
A
parietal
11
Q
What is the name of the condition when the serous pericardium gets inflamed and causes a buildup of fluid?
A
pericarditis
12
Q
What are the three layers of heart tissue?
A
epicardium, myocardium, endocardium
13
Q
which layer of the heart is contractile?
A
myocardium
14
Q
What anchors the muscle cells of the myocardium?
A
connective tissue made up of collagen and elastin
15
Q
What is the name of the layer that lines the heart chambers?
A
endocardium
16
Q
What type of cells make up the endocardium?
A
simple squamous epithelial
17
Q
Why is the endothelium smooth?
A
help with blood flow through the heart chambers
18
Q
What separates the left and right atria?
A
interatrial septum
19
Q
What separates the left and right ventricles?
A
interventricular septum
20
Q
Where does the left atria receive blood from?
A
lungs (pulmonary)
21
Q
where does the right atria receive blood from?
A
body (systemic)
22
Q
Why do the atria have weaker contractions?
A
they just need to get the blood into the ventricles and gravity helps with that
23
Q
What is the job of the ventricles?
A
expel blood into the arteries
24
Q
Why do the ventricles have stronger contractions?
A
they have to move the blood further (through the arteries)
25
Why do ventricles have thicker walls than atria?
their contractions are stronger
26
Where does blood from the left ventricle go to?
to the body via aorta
27
Where does blood from the right ventricle go?
to the lungs via pulmonary artery/trunk
28
Which direction is blood found in an artery going?
away from the heart
29
Which direction is blood found in a vein going?
back towards the heart
30
Which major vessel brings blood to the right atrium?
vena cava --> inferior = from body
superior = from the brain
31
Which major vessel brings blood to the left atrium?
pulmonary viens
32
pathway of blood:
right atrium > tricuspid valve > right ventricle > pulmonary sl valve > pulmonary artery > lungs > pulmonary vien > left atrium > mitral valve > left ventricle > aortic sl valve > aorta > body > vena cava (repeat)
33
What is coronary circulation?
blood flow to and from the myocardium
34
What is the job of coronary arteries?
deliver nutrient to the myocardium
35
What is the job of the coronary viens?
take away waste form myocardium
36
Another name for a heart attack...
myocardial infarction
37
How does blood move through the heart?
pressure gradients (area of high pressure to low pressure)
38
What is the job of valves?
prevent backflow
39
What is the name of the valves between atrium/ventricles?
atrioventricular valves
40
What is the name of the valves between ventricles and arteries?
semilunar valves
41
Name of right av valve...
tricuspid
42
Name of left av valve...
mitral
43
name of right sl valve..
pulmonary sl valve
44
Name of left sl valve...
aortic sl valve
45
what is the name of the structure that keeps av valves shut during ventricular contractions?
chordae tendinae
46
Where do the chordae tendinae attach?
valves and papillary muscles
47
What happen to persons heart rate is a valve is leaking + why?
it goes up due to inefficient pumping
48
What is the 'lub' heart noise indicating?
av valve closing
49
What is the 'dub' heart noise indicating?
sl valve closing
50
What does a heart murmur indicate?
turbulent blood flow (can be caused by a valve that doesn't fully open)
51
What carries electrical current/action potentials?
sarcolemma
52
Where are cardiac muscle cells found?
myocardium
53
Name three features of cardiac muscle cells:
1) intercalated discs/striations
2) gap junctions between cells
3) packed with desmosomes for strength
54
What is the purpose of gap junctions in cardiac muscle cells?
allow AP and ions to pass between cells
55
Why is cardiac muscle called a functional syncytium?
they're a coordinated, functional unit because of an electrical link
56
Define action potential:
rapid and predictable change in ion distribution
57
What are the three types of cardiac muscle cells?
pacemaker cells, contractile cells, conducting cells
58
Which cardiac muscle cell can make their own AP?
pacemaker cells
59
Can pacemaker cells contract?
nopeeee
60
Which cardiac muscle cells carry AP from pacemaker cells?
conducting cells
61
Which cells contract in response to action potential and make up a majority of the myocardium?
contractile cells
62
Does the contraction occur in atria or ventricles first?
atria
63
What is threshold?
cell reached a voltage where an AP can occur (point of no return )
64
What is depolarization?
cell become more +
65
What is repolarization?
cell becomes more negative
66
What is membrane potential?
unequal distribution of charged molecules on either side of the plasma membrane
67
What is pacemaker potential?
a depolarization event that causes a cell to reach threshold
68
Which ion enters the cell during depolarization?
Na+
69
Which ion enters the cell after threshold is reached?
Ca2+
70
Which ion leaves the cell during repolarization?
K+
71
Do pacemaker cells ever rest?
no, they are always depolarizing or repolarizing
72
What are the three locations in the heart you can find pacemaker cells?
1) Sinoatrial nodes
2) atrioventricular nodes
3) purkinje fibers
73
Which node in the heart is 'dominant'?
SA node
74
If the SA node fires at 80 action potentials/minute, what is your heart rate?
80 BPM
75
What division of the nervous system helps the heart slow down?
parasympathetic nervous system
76
What division of the nervous system helps the heart rate increase?
sympathetic nervous system
77
What is the parasympathetic effect?
slowing down the amount of time it takes to reach threshold
78
What hormones can increase heart rate?
adrenaline and TH
79
What is tachycardia?
resting heart rate above 100 BPM
80
What is bradycardia?
resting heart rate below 60 BPM
81
How does AP move through the atria?
freely and quickly
82
What does the AP go through to get to the ventricles?
internodal pathway
83
What are the parts of the internodal pathway?
AV node, bundle of His, purkinje fibers
84
Where do the purkinje fibers take the AP?
from the apex up the ventricular walls
85
AP pathway through the heart:
SA node > atria (freely) > AV node > bundle of HIS > purkinje fibers > ventricles
86
What is an arrhythmia?
irregular conduction of AP which leads to irregular heart beats
87
What is heart block?
AP can't pass from atrium to ventricles
88
How do you treat heart block?
insert a pacemaker
89
When producing an AP in the myocardium, what are the three phases?
1) Depolarization
2) Plateau
3) Repolarization
90
What is happening during the depolarization phase (AP in myocardium)?
Na+ channels open and close quickly
91
What is happening during the plateau phase (AP in myocardium)?
Ca2+ and K+ channels are open
92
The influx of which ion causes contraction?
Ca2+
93
Which ion has to do with the cross bridge cycle?
Ca2+
94
What is happening during the repolarization phase (AP in myocardium)?
Ca2+ and K+ channels close to end the action potential
95
Does a pump or channel facilitate active transport?
pump (channel is passive)
96
What is an EKG/ECG?
a measurement of all electrical activity in the heart at a given moment
97
What is happening in the heart when a P wave is shown?
cells in the atria are depolarizing
98
What is happening in the heart when the QRS complex shows up?
cells of the atria are repolarizing and the ventricles are depolarizing
99
When does atrial contraction occur (on an ECG)?
the PR segment
100
What is happening in the heart when the T wave is shown?
ventricles are repolarizing
101
When does ventricular contraction occur (on an ECG)?
the ST segment
102
What is the cardiac cycle?
all events associated with blood flow from the heart
103
What is systole?
the contraction phase
104
What is diastole?
the relaxation phase
105
What is happening in the first phase of the cardiac cycle?
Both the atria and ventricles are in diastole, AV Valves open, SL valves closed, passive filling of both chambers
106
What is happening during the second phase of the cardiac cycle?
atrial systole, ventricular diastole, AV valves open, SL valves closed, final 20% of blood enters ventricles, EDV is reached
107
What is happening during the 3a phase of the cardiac cycle?
isovolumetric contraction phase, ventricle starts contracting, no blood movement yet, atria enter diastole, all valves are closed (pressure in ventricles goes up)
108
What is happening in the 3b phase of the cardiac cycle?
ventricular ejection, AV closed, SL open, blood goes into arteries due to pressure gradient
109
What is happening during the fourth phase of the cardiac cycle?
Isovolumetric relaxation, ventricles enter diastole, all valves are closed, ESV reached
110
What is stroke volume and how can you calculate it?
the amount of blood that leaves the heart during ventricular ejection; SV=EDV-ESV
111
What is the wiggers diagram?
a big graph that allows us to track electrical events, mechanical events, and flow all in one place (three different y axis, time on x)
112
What is the order in which the valves open/close as shown on the wiggers pressure diagram?
AV close, SL open, SL close, AV open
113
What is cardiac output? (& how do you calculate it)
volume of blood that goes through the heart in a minute
CO=HR x SV
114
Why do more fit people have a higher stroke volume?
exercise builds cardiac muscle which allows more blood to get pumped out
115
What is cardiac reserve?
the difference in cardiac output between rest and maximum intensity
116
What are the three way to change cardiac reserve?
1) change stroke volume
2) increase efficiency
3) lower afterload
117
What is the Frank-Starling Law of the Heart?
the SV is dependent on EDV so as EDV increases, the contractions become more effeincient and when more blood is ejected the ESV goes down... together, a lower ESV and higher EDV lead to a higher SV
118
What is afterload?
pressure the ventricles have to overcome to expel blood
119
Why does a higher blood pressure lead to a higher resting heart rate?
when the arterial pressure goes up, the SL valves aren't open for as long (refer to wiggers diagram) which leads to a decrease in SV so to keep the amount of blood ejected to your body the same, the HR goes up to compensate
