Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Med 310B > cardiac > Flashcards

cardiac Flashcards

1
Q

what is the general purpose of the cardiac system?

A

deliver nutrients and oxygen
remove waste
provide thermoregulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe the general purpose of the heart?

A

serves as a pump that establishes the pressure gradient needed for blood to flow to tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

describe the general purpose of blood vessels?

A

passageways through which blood is distributed from heart to all parts of the body and back to the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

decribe the general purpose of blood?

A

a transport medium which whihc materials being transported are dissolved or suspended within

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how big is the heart?

A

approximately the size of a clenched fist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where does the heart lie in the chest?

A

midline in the thoracic cavity between sternum and spine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which part of the heart is called the base?

A

the top, broad portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which part of the heart is called the apex?

A

the bottom, pointed portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how is the heart oriented?

A

at an angle with the base to the right and apex on the left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

when beating, which part of the body does the apex beat against?

A

the left chest wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the 2 cardiovascular circulations?

A

pulmonary and systemic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the pulmonary circulation?

A

closed loop of vessels carrying blood between heart and lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the systemic circulation?

A

circuit of vessels carrying blood between the heart and other body systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the purpose of the right side of the heart;

A

pumps blood to be reoxygenated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the purpose of the left side of the heart;

A

recieves freshly oxygenated blood to be sent elsewhere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how are the right and left side of the heart generally related?

A

the volume of blood pumped by the right side will become the volume of blood pumped by the left side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the pressure and resistance flow of pulmonary circulation?

A

low pressure, low resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the pressure and resistance flow of systemic circulation?

A

high pressure, high resistence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

which side of the heart can generally be said to do more work?

A

the left ventrical since the volume is the same but pumped at a hugher pressure against higher resistence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the purpose of valves?

A

ensure blood flow is unidirectional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

when do valves open?

A

when there is a higher forward pressure gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

when do valves close?

A

when there is a higher backward pressure gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

the left and right sides of the heart contract and pump ____

A

simultaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are papillary muscles and where are they located?

A

ventricals
contract with heart contraction to secure the valve and keep the seal intact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are chordae tendinae and where are they located?

A

ventricles
fibrous tendons
heart strings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what valves are known as the semilunar valves?

A

aortic and pulmonaary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

the right AV valve is ____

A

tricuspid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

the left AV valve is ____

A

bicuspid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the fibrpus rings of the heart?

A

connective tissue that seperates the atria and ventricles. they encapsulate each valve to hold them in place during beats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

describe the endocardium;

A

a single cell thick wall that lines the inner layer of the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

descirbe the myocardium;

A

holds contractile and electrical cells that underlie spontaneous contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are the features of the cardiac wall?

A

endocardium
myocardium
epicardium
pericardial cavity
pericardial sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why does cardiac muscle have lots of mitochondria?

A

because the heart has a high energy requirement and has high oxidative tendancies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what system innervates cardiac muscle?

A

autonomic nervous system - not voluntary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

cardiac muscle fibers are connected by ____

A

intercalcated discs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

99% of cells in the heart are ____

A

contractile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

1% of cardiac cells have ____ activity that stimulate the heart

A

pace maker/autorhythmicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

do atria and ventricular cells have gap junctions?

A

no, they are seperated by non-conductive barrier (fibrous skeleton)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what are the 2 consequences of high connectivity by sepcial system?

A

1 - spontaneous impulse generated at one place spreads throughout the heart
2: all cardiac fibers contract or none do

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what are the 4 specialized conduction pathways?

A

SA node
AV node
bundle of His
purkinje fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

describe the SA node;

A

in superior vena cava of the R atria. drives regular paace

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

describe teh AV node;

A

slow things down to ensure atrial contraction before delivering to ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

describe the purkinje fibers;

A

conducts electrical signals along the wall of the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what are the 3 efficiency criteria for cardiac function?

A

1: atrial excitation and contraction must complete before ventrical contraction can begin
2: cardiac muscle excitation coordinated for heart chamber to contract as a unit
3: pair of atria and pair of ventricles coordinated as a pair that contracts siumltaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

describe the 4 steps of the spread of strial excitation;

A

1: keep atria beating together
2: 30 ms delay. keeps the atria beating before ventricles
3: AV nodal delay, 100ms, allow atria time to fully contract to fill ventricles
4: from AV node to entire cardiac purkinje system, 30 ms. keep ventricles beating together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

SA failure would lead to ____

A

abnormal pace maker activity by latent pacemakers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what is complete heart block?

A

loss of conduction between atria and ventricles. would require an atrifical pace maker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what is ectopic focus?

A

overy excitable region that depolarizes faster that SA node. can lead to premature ventricle contraction so therefore it will not have the full effective contraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is the orientation of the aortic valve?

A

approximately at the level of the sternal angle which is between the manubrium and sternal body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

veins lead ___

A

into atria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

arteries lead __-

A

out of ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

the septum refers to ___

A

the wall between the 2 halves of the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

which ventrical wall is thicker?

A

left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

the aorta is a single large artey that exits the ___ ventricle

A

left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what is resistence?

A

the opposition to flow caused in part by friction betwen the flowing blood and vessel wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

how is prolapse/eversion of the AV valves prevented?

A

by tension on the valve leaflets exerted by the chordae tendineae when the papillary muscles contract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

how is prolapse/eversion of the semilunary valves prevented?

A

when semilunary valves are swept closed, their upturned edges fit together in a deep, leak proof seam that prevents eversion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

the left AV valve is referred to as the bicuspid or ___ valve

A

mitral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

closure of the AV valve produces the ___ sound

A

lub

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

do semilunary valves have chordae tendinae?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

closure of the semilunary valves produce the ____ sound

A

dub

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

the epicardium makes up ____

A

the visceral layer of the serous pericardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

what is thge pericardial sac filled with?

A

pericardial fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

what does pericardial fluid do?

A

reduces friction between sirfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

the parietal layer of the ____ is the inner layer of the pericardial sac

A

serous pericardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

what part of the pericardial sac helps keep the heart hanging in the thoracic cavity?

A

fibrous pericardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

how do cardiac muscles orient themselves for the heart?

A

around it in a spiral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

when the heart muscle contracts, what do the muscle fibers do?

A

twist in an upward direction - sort of wringing it out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

cardiac muscle fibers are joined by ___

A

gap junctions and mechanical connections (desmosomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

what does autorhythmicity mean?

A

it means that cells can generate their own action potentials across cardica muscle membranes to cause contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

the ‘I(f)’ channel is activated upon ___

A

hyperpolerization.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

’ I(Ca,T)’ differ from longer lasting voltage gated Ca2+ channels because:

A

they open at lower membrane potentials and further depolarizes the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

once threshold is reach, the rising phase occurs due to ___

A

a large influc of Ca2+ passing through L-type channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

the falling phase is due to efflux of ___

A

K ions through ‘I(K)’ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

after action potential, the slow closure of K channels and opening of ___ channels initiates the next depolarization

A

‘I(f)’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

what is ‘I(Ca,L)’?

A

a long lasting voltage gated Ca2+ channel present in contractile ccells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

what is ‘I(K)’ responsibel for?

A

repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

what is the bundle of HIs?

A

a tract that origniates at the Av node, enters the inter-ventricular septum and divides to form right and left bundle branches. they follow the septum down and curve around the tip of the ventricular champers and travel back toward the atria along the walls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

what is fibrillation?

A

uncoordinated excitation and contraction of cardiac cells. can occur in either or both atria and ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

what is electrical defibrillation?

A

corrective measure for ventricular fibrillation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

what is the interatrial pathway?

A

SA node – left atrium (keeps atria beating together)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

what is the internodal pathway?

A

SA node — AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

what are the general purpose of contraactile cells?

A

do the mechanical work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

do contractile cells initiate their own action potentials?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

what is the general purpose of autorhythmic cells?

A

initiating and conducting action potentials responsible for contraction of working cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

what are the 5 phases of action potential in contractile cells?

A

Phase 0 - rapid depolarization
Phase 1 - rapid repolarization
Phase 2 - plateau
Phase 3 - repolarization
Phase 4 - rest

87
Q

what happens during phase 0/rapid depolarization in contractile cells?

A

cell becones less negative because of activation of Na channel and movement of Na (fast voltage gated Na+ channels)

88
Q

what happens during phase 1/rapid repolarization of contractile cells?

A

cells begin to reverse polarity toward the negative direction because of a specific activation of a K+ pathway while those fast-sodium channels close
(activation of transient outward K+ channels)

89
Q

what happens during phase 2/plateau of contractile cells?

A

long type calcium channels open during the rapid depolarization and remain open (delayed K+ channel)

90
Q

what happens during phase 3/repolarization of contractile cells?

A

closing of long calcium channels and dominant outward K+ movement (delayed K+ channel)

91
Q

what happens during phase 4/rest of contractile cells?

A

inward rectifying of Na and K channels.

92
Q

describe the pathway of excitation-contarction coupling;

A
  • action potential initiated in contractile cells
  • goes down T tubule
  • small amount of Ca2+ enter from ECF AND Ca also released from internal store in the SR - most released from here
  • cytosolic Ca2+ increased
  • troponin-tropomyosin complex in THIN filaments pulled aside
  • cross bridgin between thick and thin filaments
  • thin filaments slide inward
  • contraction
93
Q

can summation occur in cardiac muscle?

A

no

94
Q

how can electrical currents be detected in skin in the body isnt a piece of electrical equipment?

A

the body fluids are conductive!

95
Q

what do EKGs show?

A

direction and magnitude of currents over time - SUM of all electrical currents at any given time

96
Q

what cell activity is an EKG dominated by?

A

contractile cells

97
Q

what does the P wave on an EKG show and what does it look like?

A
  • a little tiny hump before the QRS
  • shows atrial depolarization prior to contraction
98
Q

what does the PR segment on an EKG show and what does it look like?

A
  • from the P wave (little hump) to the peak of the QRS segment
  • shows AV nodal delay - the time for electrical current to pass from atria to ventricals
99
Q

what does the QRS segment on an EKG show and what does it look like?

A
  • sharp peak/jump - sometimes surrpounded by 2 dipping sections before and after Q and S
  • shows ventrical depolarization where the atria is repolarizing at the same time
  • R is always present
100
Q

what does the ST segment on an EKG show and what does it look like?

A
  • the end of the QRS segment + a large hump (larger than P wave)
  • the time during which the ventricles are contracting and emptying
101
Q

what does the T wave on an EKG show and what does it look like?

A
  • a large hump (larger than P wave)
  • shows ventricular repolarizatin
102
Q

what does the TP interval look like on an EKG and what does it show?

A
  • the plateau from the end of the T wave to the start of the P wave
  • shows time during which the ventricles are relaxing and refilling before the process begins again
103
Q

why are EKG leads placed so specifically?

A

so that you can see conduction within the heart from different perspectives

104
Q

where does Lead 1 lie?

A

right arm (-) to left arm (+)

105
Q

where does Lead 2 lie?

A

right arm (-) to left leg (+)

106
Q

where does Lead 3 lie?

A

left aarm (+) to left leg (+)

107
Q

how many chest leads are there?

A

6

108
Q

how many augmented leads are there?

A

3

109
Q

where does aVF get placed?

A

left leg

110
Q

where does aVR get placed?

A

right arm

111
Q

where does aVL get placed?

A

left arm

112
Q

how many axis does the EKG show?

A

12

113
Q

where does electrical excitation originate/begin?

A

SA node

114
Q

onset of electrical excitation has a total magnitude in mostly the ____ direction

A

positive/left

115
Q

onset of electrical excitation has a total magnitude in mostly the ____ direction - in comparison to lead 2

A

a downward positive

116
Q

the QRS can represent _____

A

spread of excitation

117
Q

tachycardian can be viewed on an EKG as ____

A

extremely close QRS complexes that indicated a bpm of usually >160

118
Q

brachcardia can be viewed on an EKG as ____-

A

abnormally far apart QRS complexes indictive of a bpm <60

119
Q

what is extrasystole and how would it look on an EKG?

A
  • premature ventricular contraction
  • a strong dip between T and P outside of correct contraction timing
120
Q

what does ventricular fibrillation represent and how would it look on an EKG?

A
  • inadequate depolarization
  • would have no discernable waves at all. would be relatively small - like a scribble
121
Q

what does complete heart block represent and how would it look on an EKG?

A
  • conduction not passed from atria to ventrical
  • would have a multitude of P complexes between QRS complexes
122
Q

what does myocardial infarction represent and how would it look on an EKG?

A
  • heart attack
  • strange mountain looking QRS complexes that are not straight and sharp
123
Q

what is systole?

A

contractionn and emptying period

124
Q

what is diastole?

A

relaxation and filling period

125
Q

what is excitation-contraction coupling in the heart driven by?

A

Ca2+ release

126
Q

what is the primary store for Ca2+?

A

sarcoplasmic reticulum

127
Q

ECF concentrations of K+ and Ca2+ influence what in regards to contractile AND autorhythmic cells?

A

starting point, duration, ending point

128
Q

an elevated K+ concentration in the ECf would cause?

A

reduces membrane potential which can lead to develop ectopic contractions and ectopic pacemaker potentials

129
Q

an elevated Ca2+ concentration in the ECF would cause?

A

increases strength of contraction and lengthens action potential = less time between contractions

130
Q

what is the absolute refractory period?

A

the time when a second action potential cannot be triggered

131
Q

leads 1, 2 and 3 are known as ____ leads

A

bipolar because 2 leads are used

132
Q

why are augmented leads known as unipolar if they also use both leads?

A

only the actual potential under one electrode is recorded the other is set to 0

133
Q

what are the 4 stages of the generation of the QRS complex known as?

A

1: septal depolarization
2: apical depolarization
3: L ventricualr depolarization
4: L ventricular depolarization

134
Q

variations from normal heart rate are known as ____

A

arrhythmias

135
Q

what is it known as when all valves are closed and the ventricles are filled with all the blood that they will recieve?

A

isovolumetric ventricular contraction

136
Q

describe phase 1 (slow ventricular filling) for the right side of the heart;

A
  • atria AND ventricles are in diastole
  • vena cava has low pressure
  • right atrium has lower pressure so there is free flow between them
  • the right ventricle has lower pressure so the valve is opened allowing blood through
  • the pulmonary trunk has high pressure so its valve is closed, no blood can come through
137
Q

describe pase 2 (active ventricular filling) for the right side of the heart;

A
  • atria in systole, ventricle is diastole
  • the vena cava remains unchanged
  • the atria contracts which increases the pressure and causes a small amount of backflow into the vena cava
  • the right ventrical valve remains open as the pressure has not increased too musch
  • the pulmonary trunk loses a bit of pressure but not enough to cause the valve to open
138
Q

describe phase 3 ( ventricular emptying) for the right side of the heart;

A
  • atria in diastole, ventricle in systole
  • vena cava increases slightly
  • atria relaxes so pressure falls
  • pressure rises drastically in the ventrical so the valve shuts and ventrical contracts
  • the valve to the pulmonary trunk opens and blood enters pulmonary circulation causing an increase in pressure here
    1ST HEART SHOUND HEARD
139
Q

describe phase 4 (rapid ventricular filling) for the right side of the heart;

A
  • atria diastole, ventrical diastole
  • vena cava remains at low pressure
  • atria is also at low pressure
  • ventricular pressure drastically decreases so the valve reopens to fill with blood again
  • pressure in the pulmonary trunk is high so the valve shuts
    2ND HEART SOUND HEARD
140
Q

which side of the heart is constantly under higher pressure?

A

left

141
Q

describe phase 1 (slow ventricular filling) for the left side of the heart;

A
  • atria AND ventricles in diastole
  • pulmonary vein is at low pressure
  • atria is at low pressure
  • ventricle is at low pressure so the valve is open and slowly filling with blood
  • aorta is at extremely high pressure so the valve is shut
142
Q

describe pase 2 (active ventricular filling) for the left side of the heart;

A
  • atria systole, ventricle diastole
  • pulmonary vein is at low pressure
  • atria increases is pressure so there is backflow
  • atria contracts
  • pushes blood into ventricle
  • aorta pressure decreases but not enough to open valve
143
Q

describe phase 3 ( ventricular emptying) for the left side of the heart;

A
  • atria diastole, ventrical systole
  • pulmonary vein is at low pressure
  • atria decreases in pressure as it relaxes
  • ventrical drastically increases is pressure so valve shuts between atria
  • similar pressure in aorta and ventrical causes opening of valve into systemic circulation
    1ST HEART SOUND HEART
144
Q

describe phase 4 (rapid ventricular filling) for the left side of the heart;

A
  • atria AND ventricle in diastole
  • pulmonary vein is low pressure
  • atria is low pressure
  • pressure in ventrical drops and relaxes so valve reopens between atria and ventricle
  • pressure stays high in aorta so the valve shuts
    2ND HEART SHOUND HEARD
145
Q

around how long does systole last?

A

300 ms

146
Q

around how long does diastole last?

A

500 ms

147
Q

around hoe long does the entire cardiac cycle last?

A

800 ms

148
Q

during excercise what volume decreases?

A

stroke volume - ventricular volume from end diastole to end systoliv
the atria pumps harder to keep up

149
Q

is filling highly impaired during excercise?

A

nope! much of ventricular filling occurs early in diastole during rapid filling

150
Q

stenotic semilunar valve causes what kind of sound?
what is the defect?
when is the murmur timed?

A

lub-whistle-dub
a valve that should be opne during systole is not opened all the way
systolic

151
Q

stenotic av valve causes what kind of sound?
what is the decfect?
when is the murmur timed?

A

lub-dub-whistle
a valve that should be open during diastole does not open all the way
diastolic

152
Q

insufficient AV valve causes what kind of sound?
what is the defect?
when is the murmur timed?

A

lub-swish-dub
a valve that should be closed during systole does not fully close
systolic

153
Q

insufficient semilunar valve causes what kind of sound?
what is the defect?
when is the murmur timed?

A

lub-dub-swish
a valve that should be closed durin diastole does not fully close
diastolic

154
Q

what is cardiac output?

A

the volume of blood ejected by each ventricle each minute

155
Q

is cardiac output through the pulmonary and systemic circulations equal?

A

yes

156
Q

what is the equation for determining cardiac output?

A

heart rate x stroke volume

157
Q

what is stroke volume?

A

how much blood is pumped OUT

158
Q

how can heart rate be varied?

A

by altering balance of parasympathetic and sympathetic influence

159
Q

what nerve does the parasympathetic system have control over?

A

vagus

160
Q

what nerve does sympathetic system have control over?

A

cardiac

161
Q

what is average heart rate?

A

70 bpm

162
Q

where are the cardio- inhibitory/accelatory centers located?

A

in the medulla

163
Q

influence of the PNS is to ____ heart rate

A

decrease

164
Q

describe how the PNS decreases heart rate;

A
  • vagus nerve releases acetylcholine that increases potassium permeability of the SA node (hyperpolarizes SA increasing neg potential and bringing it further away from threshold)
  • slowing of Ca2+ inward shortens the plateau phase causing weaker atrial contraction
  • this slows down the closure of K+ channels, decreases the AV nodes excitability and increases AV nodal delay
  • no effect on ventrical contraction
  • slows the time to reach the threshold and AV node
165
Q

influence of the SNS is to _____ heart rate

A

increase

166
Q

describe how the SNS increases heart rate;

A
  • the SA node is stimulated by norepi
  • noepi decreases the time to reach threshold which results in more frequent action potentials and speeds their spread through the conduction pathways
  • the atrial and ventricle contractile cells beat more forcefully due to higher Ca2+ permeability AND enhanced excitation-contraction coupling
167
Q

how is stroke volume calculated?

A

end diastolic violume - end systolic volume

168
Q

what is the intrinsic control of stroke volume?

A

preload - extent of venous return

169
Q

what is the extrinsic control of stroke volume?

A

sympathetic activity

170
Q

how do intrinsic and extrinsic controls increase stroke volume?

A

increasing strength of heart contraction (contractility)

171
Q

what is preload?

A

the initial stretching of the cardiomyocytes prior to contraction ( related to sarcomere length at the end of diastole)

172
Q

what is contractility?

A

relative effectiveness or strength of the ventricular pump

173
Q

what is afterload?

A

the pressure that each ventricle has to work against when pumping blood

174
Q

waht are the 3 determinants of stroke volume?

A

preload
contractility
afterload

175
Q

what is intropy?

A

how much the muscle can contract

176
Q

what increases ventricular preload?

A

atrial intropy
venous blood volume
venous pressure
ventricular compliance
outflow resistance

177
Q

what decreases ventricular preload?

A

heart rate
ventricular intropy
inflow resistance
venous conpliance

178
Q

the SNS shifts the frank-starling curve to the _____

A

left

179
Q

what does the ejection fraction represent?

A

the % of blood pumped out of the heart for every beat

180
Q

what is the equation for the ejection fraction?

A

stroke volume - end diastolic volume

181
Q

what is the average resting stroke volume?

A

70 mL per stroke

182
Q

what is the average cardiac output?

A

5L/min

183
Q

what is cardiac reserve?

A

the difference between the cardiac output at rest and at maximum exercise/exertion

184
Q

what part of the heart does the vagus nerve primarily innervate?

A

atria, particularly SA and AV nodes

185
Q

what part of the heart does the cardiac nerve primarily innervate?

A

ventricles

186
Q

acetylcholine released from the vagus nerve binds to ___

A

muscarinic receptors coupled to inhibitory G protein reducing cAMP pathway

187
Q

norepi binds to ____

A

beta-1 adernergic receptors coupled to stimulatory G protein accelerating cAMP pathway

188
Q

even at rest there is predominant _____ input which provides continuous _____ of heart rate

A

parasympathetic
inhibition

189
Q

what does intrinsic control refer to?

A

ann inherent ability of the heart to adjust stroke volume ( heart pumps out whatever enters)

190
Q

what does the frank-starling curve show?

A

the relationship between stroke colume and end diastole volume

191
Q

arterial bp is ___________
aortic bp is _______ for the left ventriclce
pulmonic bp is _________ for the right ventricle

A

afterload

192
Q

what factor will increase the pressure required of the ventricles to eject blood?

A

high bp of a stenotic valve

193
Q

an increase in afterload _________ stroke volume

A

decreases

194
Q

what is the word for enlarged heart muscle?

A

hypertrophy

195
Q

what is heart failure?

A

the inability of the cardiac output to keep pace withe the body’s demands for nutrients and removal of waste

196
Q

does heart failure only ever affect one ventricle?

A

no. it can affect one or both ventricles

197
Q

a ventricles inability to pump enough blood can cause __-

A

blood to become congested or backed up in veins upstream of the ventricle

198
Q

what causes heart failure?

A

heart attack
impaired coronary circulation
prolonged pumping against chronic afterload

199
Q

a decrease in cardiac contractility (weakened heart) is a defect that causes ____

A

heart failure

200
Q

what is decompensated heart failure?

A

the point at which the heart can no longer pump out a normal stroke volume despite compensatory measures

201
Q

congestive heart failure is also know as __-

A

decompensated heart failure

202
Q

describe cogestive heart failure;

A
  • cardiac muscle fibers are stretched to operating in descending limb of the length-tension curve of the frank-starling law
  • blood cannot enter and be pumped out and the venous system dams up
203
Q

heart failure is know as canads ____

A

silent epidemic

204
Q

the heart muscle is supplied by oxygen and nutrients from what circulatory system?

A

coronary NOT from blood within the chambers

205
Q

the heart recieves most of its own blood supply that occurs during ___

A

diastole

206
Q

why does the heart recieve most of the blood from systole instead of diastole?

A

during systole, coronary vessvels are compressed by the contracting heart muscle

207
Q

why does coronary blood flow vary?

A

to keep pace with cardiac oxygen needs

208
Q

increasing the metabolic activity of cardiac muscle cells ( or increasing the need for oxygen) in turn causes;

A
  • increase in adenosine
  • vasodilation of coronary vessel
  • increase in blood flow to cardiac muscle cells
  • increased availability of oxygen to meet the need
209
Q

what is atherosclerotic coronary artery disease?

A

pathological changes within coronary walls that diminish bloodflow through the vessels

210
Q

what is the leading cause of death in canada?

A

coronary artery disease

211
Q

what can coronary artery disease cause?

A

myocardial ischemia and possible acute myocardial infarction

212
Q

what are the 3 mechanisms of coronary artery disease?

A
  • profound vascular spasms of coronary arteries
  • formation of atherosclerotic plaques
  • thromboembolism
213
Q

what would cause immediate death in a patient with acute myocardial infarction?

A
  • the heart is too eak to pump effectively to support body tissues
  • fatal ventricular fibrillation caused by damage to specialized conducting tissue occuring because the weakened heart was deprived of oxygen
214
Q

waht would cause delayed death (from complications) in a patient with actue myocardial infarction?

A
  • fatal rupture of the degenerating area of the heart wall
  • slowly progressing congestive heart failure where the heart becomes unable to pump out all the blood returned to it

Med 310B (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions