Cardiovascular Physiology Flashcards Preview

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Flashcards in Cardiovascular Physiology Deck (55)
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0
Q

What is ANP (atrial natriuretic peptide) released in response to?

A

Increased atrial pressure

1
Q

How many liters of blood per minute is pumped in a 70kg man

A

5-6 liters

2
Q

What is BNP (b-type natriuretic peptide) released in response to?

A

overstretched ventricles

3
Q

Intercalated discs allow the heart to contract in synchrony as one unit, what is this called?

A

Syncytium

4
Q

What is happening with the ions in the initial repolarization in cardiac muscle contraction?

A

Inactivation of Na+ influx

K+ efflux

5
Q

What is happening in the plateau phase of the cardiac muscle contraction? (ions)

A

Ca++ influx through L-type Ca++ channels

6
Q

What determines the force of contraction of the myocardial cell?

A

The amount of intracellular calcium

7
Q

No action potential can be initiated regardless of the stimulus strength, what refractory period is this?

A

Absolute refractory period

8
Q

An action potential can be elicited, however a greater stimulus is needed, what refractory period is this?

A

Relative refractory period

9
Q

Why is cardiac muscle incapable of sustained contraction (tetany) as in skeletal muscle?

A

Because of the relatively long refractory period

10
Q

What is the Frank-Sterling law?

A

Cardiac output is directly proportional to venous return

11
Q

The 1st heart sound is due to what?

A

Closure of the tricuspid and mitral valves

12
Q

The 2nd heart sound is due to what?

A

Closure of the pulmonary and aortic valves

13
Q

3rd heart sound occurs when?

A

After the 2nd heart sound and is seen in congestive heart failure

14
Q

The 4th heart sound is heard when?

A

Before the 1st heart sound and is seen in hypertrophic ventricles

15
Q

Systole (contraction) occurs between which heart sounds?

A

1st and 2nd

16
Q

Diastole (relaxation) occurs between which heart sounds?

A

2nd and 1st

17
Q

If there is a prolonged PR interval (>200 milliseconds)

A

1st degree AV block

18
Q

If there is progressive prolongation of the PR interval with dropped beats

A

2nd degree AV block (Mobitz 1- Wenckebach phenomenon)

19
Q

Isovolumic contraction occurs when?

A

Between the closure of the AV valves and the opening of the aortic valve

20
Q

Increase in pressure without change in volume is called what?

A

Isovolumic contraction

21
Q

What is it called when only 70ml of the 120ml of blood is expelled from the ventricle?

A

Ejection fraction

22
Q

A decrease in the ventricular pressure without a change in the volume is called?

A

Isovolumic relaxation

23
Q

When does isovolumic relaxation occur?

A

Between the closing of the aortic valve and the opening of the AV valves

24
Q

Sympathetic control of heart rate comes from which vertebral levels and which sympathetic ganglia?

A

T1-T5, middle and inferior cervical ganglia

25
Q

What is it called when the sympathetic nervous system increases heart rate?

A

Positive chronotropism

26
Q

How does the sympathetic nervous system increase the heart rate?

A

By increasing the rate of Phase 4

27
Q

What is it called when there is an increase in conduction velocity?

A

Positive dromotropism

28
Q

How does the sympathetic nervous system increase conduction velocity?

A

By decreasing the PR interval

29
Q

What is it called when there is an increase in force of contraction in the heart?

A

Positive inotropism

30
Q

How does the sympathetic nervous system increase force of contraction?

A

By increasing Ca++ influx in Phase 2

31
Q

Which CN controls parasympathetic control to the heart?

A

Vagus through its cardiac branches

32
Q

Cardiac Output x Peripheral Resistance = ?

A

Blood Pressure

33
Q

Stroke Volume x Heat Rate = ?

A

Cardiac Ouput

34
Q

Afferent high pressure sensors (baroreceptors) information in the carotid sinus are carried in which nerve?

A

Cranial nerve IX

35
Q

Afferent high pressure sensors (baroreceptors) information in the aortic arch is carried in which nerve?

A

Cranial nerve X

36
Q

CN IX and CN X carry afferent high pressure baroreceptor information to which area of the brain?

A

The Medulla

37
Q

Where are the low pressure baroreceptors located?

A

SVC, IVC and the right atrium

38
Q

What do low pressure baroreceptors monitor?

A

Volume

39
Q

What is Poiseuille’s Law?

A

Peripheral resistance is directly proportional to viscosity of blood and lenth of the vessel and inversely proportional to the radius of the vessel raised to the 4th power

40
Q

The greatest resistance in the vascular system is offered where?

A

Arterioles

41
Q

Blood flow through a tubular structure is governed by which law?

A

La Place’s law

42
Q

What is La Place’s law?

A

The pressure within a blood vessel is related to the tension, size and shape of the vessel

43
Q

What is blood flow inversely proportional to?

A

The diameter of the blood vessel

44
Q

How much of the total blood volume is contained within the venous system?

A

60%

45
Q

How much of the total blood volume is contained within the pulmonary system?

A

15%

46
Q

How much of the total blood volume is contained within the capillaries?

A

5%

48
Q

Where is blood flow the greatest?

A

Within the arteries and veins

49
Q

Where is the least amount of blood flow?

A

The capillaries

51
Q

How much of the total blood volume is contained within the arteries and arterioles?

A

20%

52
Q

Pressure which tends to force fluids out into the interstitial space (+)

A

Intracapillary hydrostatic

53
Q

Pressure which tends to pull fluids into the capillary (-)

A

Intracapillary oncotic pressure

54
Q

Pressure which forces fluids into the capillary

A

Interstitial hydrostatic pressure

55
Q

Pressure which pulls fluid out of the capillary

A

Interstitial oncotic pressure

56
Q

Prolonged exercise leads to cardiac muscle hypertrophy which leads to?

A

Athletic Heart Syndrome