Brainscape's Knowledge GenomeTM

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


See full index

USMLE Step 1 > Cardiovascular System > Flashcards

Cardiovascular System Flashcards

You may prefer our related Brainscape-certified flashcards:
USMLE® Step 1 flashcards
1
Q

Norepinephrine is a _______ that acts on ___ receptors.

A
  1. Neurotransmitter

2. B1 (beta 1 receptors)

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

What do phase 0 and 3 of the action potential graph stand for?

A

Phase 0 = action potential

Phase 3 = repolarization

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

Phases of the cardiac action potential.

Phase 0:
Phase 1:
Phase 2:
Phase 3:
Phase 4:
A

Phase 0: upstroke, action potential, Na+ conductance

Phase 1: initial brief repolarization

Phase 2: Plateau, transient Ca2+ conductance leads to inward Ca2+ current, both inward and outward current are the same

Phase 3: repolarization, Ca2+ conductance decreases and K+ conductance increases, K+ outward (Ik1) conductance increases leading to repolarization

Phase 4: resting membrane potential. Inward and outward currents of K+ are equal.

Plateaus occur when charge fluxes balance each other out.

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

Sinoatrial Cardiac Cycle

Phase 0:
Phase 1:
Phase 2:
Phase 3:
Phase 4:
A

Phase 0: upstroke, action potential, Ca2+ conductance

Phase 1: does not exist here

Phase 2: Does not exist here

Phase 3: repolarization, Increase K+ conductance increases, K+ outward conductance increases leading to repolarization

Phase 4: slow depolarization

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

This is related to the right atrial pressure and is called the END DIASTOLIC VOLUME (EDV):

A

Perload

Note: An increase in venous return leads to an increase in EDV

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

An increase in preload refers to:

A

An increase in end diastolic volume (EDV) and an increase in venous return

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

The slope on the venous return curve of the cardiac vascular function curve is determined by

A

The resistance of arterioles.

BRS physiology, pg. 79, 5th Ed

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

Stroke volume =

A

EDV - ESV

EDV= end diastolic volume

ESV = end systolic volume

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

Cardiac output =

A

Stroke volume x heart rate

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

Ejection fraction =

A

Stroke volume / EDV

(EDV - ESV)/ EDV

Related to ventricular contractility and a normal value is 55%

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

Stroke work =

A

Pressure x Volume

Aortic Pressure x Stroke Volume

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

Cardiac Output =

A

Oxygen consumption / (O2 pulmonary vein - O2 pulmonary artery)

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

What is the S4 heart sound represent?

A

Filling of the ventricles by atrial systole.

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

What describes

1) activation of atria
2) precedes or come before the P wave
3) causes the S4 heart sound
4) a wave of venous pulse

A

atrial systole

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

what describes:

1) begins at onset of the QRS wave, which represents activation of ventricles
2) S1 heart sound occurs
3) AV valve closes, ventricular pressure > atrial pressure and corresponds to the first heart sound
4) Splitting in first heart sound may be because the mitral valve closes before the tricuspid

A

Isovolumetric Ventricular Contraction

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

What describes:

1) ventricular pressure reaches its maximum
2) aortic valve opens, ventricular pressure > aortic pressure
3) stroke volume is ejected during this phase
4) onset of the T wave occurs (ventricle contract and rapid ejection)

A

Rapid Ventricular Ejection

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

What describes :

1) decreasing ventricular ejection and decreasing atrial pressure
2) atrial filling continues

A

Reduced Ventricular Ejection

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

What describes:

1) end of the T wave
2) during this phase, closure of the aortic valve and then pulmonary valve occurs
3) S2 heart sound occurs
4) Mitral valve opens, when the atrial pressure > ventricular pressure

A

Isovolumetric Ventricular Relaxation

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

What describes:

1) Mitral valve opens and ventricular filling from atrium begins
2) S3 heart sound occurs (Normal in children, abnormal in adults)

A

Rapid Ventricular Filling

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

What describes:

1) Longest phase of the cardiac cycle
2) Ventricular filling continues but at a slower rate

A

Reduced Ventricular Filling (diastasis)

23
Q

Heart sound S1 occur in

A

Isovolumetric contraction and systole. It is the loudest heart sound.

24
Q

Heart sound S2 occur in

A

Isovolumetric relaxation; aortic and pulmonary valve closure; during diastole.

25
Q

Heart sound S3 occur in

A

Only heard in children and pregnant women; abnormal in healthy adults.

Diseased adults have CHF, mitral regurgitation and associated with increased filling pressures.

26
Q

Heart sound S4 occur in

A

Known as the “Atrial kick”

Occurs in late diastole. S4 heart sound is associated with ventricular hypertrophy.

27
Q

Nitric Oxide

A

NO is an endothelial derived relaxing factor (EDRF). EDRFs cause relaxation of vascular smooth muscles.

28
Q

What organ/ circulatory system is describe to:

1) use 5% cardiac output
2) local metabolite control
3) vasoactive metabolite = adenosine
4) metabolite causes compression during systole

A

Coronary Circulation

29
Q

What organ/ circulatory system is describe to:

1) use 15% cardiac output
2) local metabolite control
3) vasoactive metabolite = CO2 and H+
4) increase in intracranial pressure causes a decrease in cerebral blood flow

A

Cerebral Circulation

30
Q

What organ/ circulatory system is describe to:

1) use 20% cardiac output
2) local metabolite control
3) vasoactive metabolite = lactate, K+, and adenosine
4) sympathetic control is very important here (a1 receptors cause vasoconstriction; b2 receptors cause vasodilation)
5) muscular activity cause temporary decrease in blood flow

A

Muscle Circulation

31
Q

What organ/ circulatory system is describe to:

1) use 5% cardiac output
2) local metabolite control is its least important mechanism of control
3) vasoactive metabolite = not important in this case
4) sympathetic control is its most important mechanism

A

Skin Circulation

32
Q

What organ/ circulatory system is describe to:

1) use 100% cardiac output
2) most important local metabolite control is hypoxia
3) vasoactive metabolite = hypoxia
4) hypoxia causes vasoconstriction (eliminates) non-functioning components

A

Pulmonary Circulation

33
Q

Name vasodilator metabolites:

A

1) CO2
2) H+
3) K+
4) Lactate
5) Adenosine

All are release because the tissue supply of O2 is matched to the tissue demand for O2, become out of balance. They lead to 1) increased arteriolar vasodilation, 2) increased blood flow 3) increased oxygen delivery

34
Q

An increase in blood flow to an organ occurs after period of occlusion is called:

A

Reactive hyperemia

35
Q

An increase in blood flow due to increase in skeletal muscle activity is called:

A

Active hyperemia

36
Q

Histamine causes:

A

1) arteriolar dilation and
2) venous constriction

The combined effect of both arteriole dilation and venous constriction causes increased Pc of the Starling equation which leads to increased filtration resulting in edema. Tissue trauma causes release of histamine.

37
Q

Bradykinin causes:

A

1) arteriolar dilation and
2) venous constriction

The combined effect of both arteriole dilation and venous constriction causes increased Pc of the Starling equation which leads to increased filtration resulting in edema. Similar to histamine.

38
Q

Serotonin (5-hydroxytryptamine) causes:

A

1) arteriolar constriction

Serotonin is release when blood vessels are damaged and leads vasoconstriction to prevent blood loss.

39
Q

Prostaglandins cause:

Name 4 types of prostaglandins:

A

1) Prostacyclin: vasodilator in several vascular bed
2) E-series prostaglandins: vasodilateeerrrs
3) F-series prostaglandins: vasoconstrictors
4) Thromboxane A2: vasoconstrictor

40
Q

Most important local vasodilator for cerebral circulation:

A

CO2

41
Q

Sympathetic innervation is primary regulator of blood flow to the skeletal muscle:

A

at rest.

Arterioles are densely innervated densely sympathetically fibers; veins are innervated less densely.

42
Q

Sympathetic innervation of a1 (alpha 1) receptors cause:

A

Vasoconstriction

43
Q

Sympathetic innervation of b2 (beta 2) receptors cause:

A

Vasodilation

44
Q

Low cerebral pressure causes

A

Fainting

45
Q

A. Initial responses to standing:

B. Compensatory mechanisms:

A

A. Arterial blood pressure - decrease; cardiac output - decrease; stroke volume - decrease; Central venous pressure - decrease;

heart rate - no change; TPR - no change

B. Compensatory Mechanism: ALL INCrease
Arterial blood pressure
heart rate
cardiac output
stroke volume
TPR
Central venous pressure
46
Q

No P wave means the pacemaker is in the:

A

AV (atrioventricular) node.

47
Q

What are the two isolectric regions of action potential?

A

PR and ST intervals

P wave (involves atria)
ST wave (involves ventricles)
48
Q

Fetal pulmonary blood flow volume.

A

Pulmonary fetal blood flow is nearly zero.

49
Q

What receptor mediates constriction of arteriolar smooth muscle?

A

a1 receptors (alpha-1)

50
Q

Diaphoresis means

A

Excessive sweating

USMLE Step 1 (10 decks)

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