Brainscape's Knowledge GenomeTM

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


See full index

The heart > Cardiac function > Flashcards

Cardiac function Flashcards

1
Q

What does LVEDD stand for in cardiac measurements?

A

Distance between walls

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

What does WT mean in cardiac measurements?

A

Wall thickness

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

Do we want a more compliant/stretchy heart muscle or one with lots of resistance?

A

More compliant/stretchy muscle

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

How much we fill the heart up with blood is positively OR negatively related to strength of contraction?

A

Positively

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

What 3 things is the parasympathetic nervous system wired into in the heart to have an effect on the heart rate?

A

SA node, AV node and atrial muscle.

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

What two factors does the sympathetic nervous system have?

A

Chronotropic and inotropic

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

What muscles of the heart does the sympathetic nervous system initiate?

A

The muscles of the ventricles and atria.

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

Which one (PNS and SNS) decrease and increase HR?

A

PNS decreases HR

SNS increases HR

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

How much could the SNS increase HR by?

A

300%

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

Is the normal HR (72bpm) dominated by the PNS or the SNS??

A

The PNS

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

HR increases by how many bpm per 1 MET

A

10 bpm

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

What impact does SNS have on contractility?

A

Increases it compared to control.

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

What effect does a bigger Left Ventricle have on SV?

A

bigger SV

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

Why do we see an increase in SV from an athletes bigger left ventricle?

A

Because the ejection fraction increases.

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

True or False…a healthy myocardium does not stretch as blood fills ventricles?

A

False

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

What mechanism does the stretchy myocardium help with?

A

The Frank-Starling Mechanism

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

what does a Pericardiectomy do to the SV and Q?

A

increase both

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

what is a pericardium?

A

wrapper around heart

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

What intrinsic control does the Frank-Starling mechanism have through increase stretching of walls?

A

increase strength of contraction

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

How does the frank starling mechanism increase strength of contraction?

A

Stores energy so re-coils and double the force

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

True or false? Cardiac muscle has a similar length-tension properties to skeletal muscles?

A

True

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

Does the cardiac muscle normal operate well below or above the optimum length?

A

Below

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

What does increasing the ventricular volume do to the ventricular muscle length?

A

It stretches the ventricular muscle towards optimum length

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

What happens if you overstretch the muscle?

A

contractile force decreases

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

Why does the contractile force decrease with being overstretched?

A

lose ability for actin and myosin to overlap and work

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

Why is venous return important?

A

Because if no blood is returned to the heart there’s nothing to pump

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

What is the typical blood volume in adults?

A

5 litres

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

Why might blood volume decrease?

A

Due to haemorrhage or dehydration.

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

How much blood resides in the veins at rest due to having excess blood?

A

Two thirds

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

True or false? the body has insufficient blood needed for maximal exercise.

A

True

31
Q

What 6 things that increase which are causes of vasodilation?

A

Nitric oxide, bradykinin, prostagladins, K+, CO2, lactate

32
Q

What decreases to cause vasodilation?

A

Local decrease in PO2

33
Q

What releases nitric oxide?

A

the endothelium

34
Q

What is Bradykinin and prostagladins?

A

An inflammation marker

35
Q

What causes vasoconstriction?

A

Increase in SNS activity releases NE - and this acts on a-receptors to cause contriction

36
Q

What causes leakage of K?

A

Muscles de-polarise and re-polarise

37
Q

What is a trigger for increase in blood flow?

A

Hypoxia which is related to exercise

38
Q

What percent of blood resides in the venous system at rest?

A

70%

39
Q

What happens to the venous smooth muscle during exercise?

A

Constriction

40
Q

What percent of blood shunting occurs through venoconstriction?

A

20%

41
Q

What do the valves in the veins do?

A

Prevent back flow of blood

42
Q

What 2 ways does blood move through the veins?

A

By the action of nearby active muscles and/or by the contraction of smooth muscle bands within the veins themselves

43
Q

What does the ventricular return pumps do to actively suck blood back in towards heart?

A

High pressure during contraction then low pressure during relaxation which creates a vacuum sucking blood towards the heart.

44
Q

What does ventricular rotation do to the heart in systole?

A

Wrings blood out

45
Q

What does ventricular rotation do to the heart in diastole?

A

Twist, recoils to such blood in.

46
Q

Does pressure increase or decrease in thorax during expiration?

A

Increases

47
Q

What happens to blood during expiration?

A

Back to heart

48
Q

What happens to the blood during inspiration?

A

Vacuum created to suck blood towards heart.

49
Q

What is squeezed during breathing which facilitates blood back to the heart?

A

The vena Cava

50
Q

What is Afterload?

A

How much blood is left in the heart at the end of contraction (end systolic volume)

51
Q

What 6 things does the heart have to pump against?

A
  • Volume of blood
  • Pressure in aorta
  • Compliance of aorta
  • Size of pulmonary/aorta lumen
  • Inertial component of the ejecting blood column
  • Systemic vascular resistance
52
Q

As increase arterial pressure more than 150mmHg what happens?

A

Start to decrease cardiac output

53
Q

What are effects of increased afterload in the acute phase?

A

SV will be reduced and reduction in velocity of contraction and ejection

54
Q

What happens to myocardial O2 consumption from an increased afterload?

A

Marked increase

55
Q

What is a compensation mechanism to restore SV?

A

Preload increasing

56
Q

What do Mechanoreceptors detect?

A

Stretch and muscle contraction

57
Q

What do mechanoreceptors do in order to increase SNS activity?

A

Send afferent signal to the brain

58
Q

what type of receptors are mechanoreceptors?

A

Type III afferent receptors

59
Q

What four things are metaboreceptors sensitive to?

A

Increased lactate, phosphate and prostagladins, and decreased pH

60
Q

What are metaboreceptors?

A

Chemical sensing sites that are activated

61
Q

What happens when the metaboreceptors sense the things and how does this facilitate?

A

Increase HR and this increase in HR facilitates returning of these back to normal level

62
Q

Where are the baroreceptors?

A

In the walls of carotid sinus and aortic arch

63
Q

What do baroreceptors sense and what is activated from this?

A

Arterial pressure which activates stretch and increased signals to brain

64
Q

What do the afferent nerves IX(carotid) and X(aortic arch) trigger in the brain?

A

to decreased SNS and increase PNS

65
Q

Blocking signals from baroreceptors allows what and how does this effect HR and Q?

A

Vasodilation and decreases HR and Q which decreases BP

66
Q

True or false? Baroreceptors inhibited when BP falls below normal range

A

True (note: Baroreceptors decrease BP)

67
Q

What happens to baroreflex during exercise?

A

reset to a higher operating pressure

68
Q

Why does the baroreflex reset to higher with exercise?

A

So that Q and HR can still increase with exercise which is healthy

69
Q

Where are chemoreceptors found?

A

In carotid sinus and aortic arch

70
Q

What do chemoreceptor sense?

A

High levels of CO2 in blood

71
Q

What does high levels of CO2 in the blood trigger?

A

Brain to increase SNS and decrease PNS = increase HR

72
Q

What elicits tachycardia?

A

Increased cardiac filling

73
Q

What does the bainbridge reflex do to HR and SV and why?

A

Increase HR and SV due to increased venous return and stretch receptors detecting increase blood volume

74
Q

What does the bainbridge relex do to the firing rate to the brain?

A

Increase

The heart (6 decks)

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