Lecture 7&8 Cardiac Output, resistance and flow blood pressure Part 1 Flashcards

1
Q

What is Heart Rate?

A

(HR) The number of contractions per minute

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2
Q

What is Stroke volume?

A

Stroke volume or SV is the volume of blood ejected per contraction

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3
Q

What is Cardiac output

A

Cardiac Output (CO) is the volume of blood pumped out of the left ventricle (right ventricle) per minute

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4
Q

What is Venous Return?

A

The volume of blood returning to the heart right or left ventricle per minute

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5
Q

What does this equation mean? CO = HR x SV

A

Cardiac output(l/min) = Heart Rate(Beats/min) times Stroke Volume (ml/beat). The answer will be in ml (1000ml) and will need to be converted to Litres (1L)

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6
Q

True or false? Sympathetic activation increases HR

A

True

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7
Q

True or false? Sympathetic activation decreases HR

A

False

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8
Q

True or false? parasympathetic activation increases HR

A

False

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9
Q

True or false? parasympathetic activation decreases HR

A

True

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10
Q

Hormones such as adrenaline or noradrenaline act on adrenergic receptors (Beta receptors) from the parasympathetic or sympathetic?

A

sympathetic

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11
Q

What is the difference between alpha and beta receptors?

A

Beta receptors are on the heart, alpha receptors are in the arteries or veins

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12
Q

What are the three ways we can increase stroke volume?

A

Increase pre-load (end diastolic volume) decrease after-load (aortic blood pressure) Increasing contractility

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13
Q

Pre-load is defined as what?

A

The degree of stretch of the ventricular wall prior to contraction.

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14
Q

For practical purposes, what is measured as a ventricular end-diastolic volume?

A

Pre-load

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15
Q

After-load is defined as what?

A

the pressure that the ventricles must overcome to eject blood.

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16
Q

The aortic pressure (diastolic) at the time the aortic valve opens is defined as Pre-load or After-load?

A

After-load

17
Q

Is this pre-load or After-load?

A

After-Load

18
Q

Is this Pre-load or After-load?

A

Preload

19
Q

An increase in venous return will result in what?

A

An increase in end-diastolic ventricular volume

20
Q

An increase in end-diastolic ventricular volume results in what?

A

An increasd force of ventricular contraction

21
Q

An increasd force of ventricular contraction results in what?

A

An increase stroke volume

22
Q

An increase stroke volume results in what?

A

an increase cardiac output

23
Q

An increase in after-load results in what?

A

Reduced stroke volume

24
Q

Reduced stroke volume results in what?

A

increase end-systolic ventricular volume

25
Q

increase end-systolic ventricular volume results in what?

A

increased end-diastolic ventricular volume

26
Q

increased end-diastolic ventricular volume results in what?

A

increased force of contraction

27
Q

increased force of contraction results in what?

A

stroke volume incrases, back towards original value.

28
Q

Cardiac contractility is defined as what?

A

the ability of the heart to contract, at any given end-diastolic ventricular volume.

29
Q

Increases in cardiac contractility are caused by what?

A

activation of cardiac sympathetic nerves or an increase in circulating adrenaline

30
Q

Decreases in cardiac contractility are caused by what?

A

activation of cardiac parasympathetic nerves that produces a decrease in myocardial intracellular

31
Q

What are the three factors that control the venous return?

A

Skeletal muscle pump (increases VP Peripheral)

Respiratory pump (decreases VP Central)

Sympathetic venoconstriction (increases VP Peripheral)

32
Q

What is Venoconstriction?

A

Venoconstriction is the contraction of skeletal muscle to push blood back up to the heart

33
Q

How do you find out the mean arterial pressure

A

Find out the diastolic pressure, add a third of the Pulse pressure.

Pulse pressure is systolic pressure minus diastolic pressure,

Divide the PP by 3 to get a third.

DBP + 1/3PP
MAP = 80 (120-80)/3=93.33