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(YEAR 1) PBLs > CR: PBL 2 (Heart and Exercise) > Flashcards

CR: PBL 2 (Heart and Exercise) Flashcards

1
Q

Define pulse pressure

A

Systolic BP - Diastolic BP (difference)

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2
Q

Define mean arterial pressure

A

Arithmetic mean of arterial blood pressure (CO x TPR)

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3
Q

Define pre-load

A

Pressure of blood in the ventricle before contraction

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4
Q

What is central venous pressure?

A

Pressure of blood in the great veins as they enter the right atrium

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5
Q

Define venous return

A

The volume of blood returning to the right atrium in one minute

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6
Q

Define total peripheral resistance

A

Resistance to the flow of blood in the whole system (MAP/CO)

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7
Q

Define systemic vascular resistance

A

Resistance to blood flow offered by all of the systemic vasculature (not pulmonary) - (MAP - RA pressure)/CO

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8
Q

Define ‘ejection fraction’

A

Proportion of EDV which is ejected by contraction

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9
Q

What is meant by ‘central command’

A

The anticipatory response of the autonomic nervous system to exercise which causes CO and arteriole adjustment

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10
Q

How does the cardiovascular system respond to exercise immediately?

A

Local chemicals cause arteriole dilation (lactic acid, nitric oxide and increased CO2, H+ and K+ levels)

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11
Q

How does the autonomic nervous system respond to exercise?

A

Sympathetic fight or flight response initiated:
a1 receptor –> causes blood shunting from digestion
B1 receptor –> increases HR and contraction force (SV)
B2 –> bronchodilation

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12
Q

Why does heart rate change after exercise?

A

Increased sympathetic stimulation to SAN

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13
Q

Why does systolic blood pressure change after exercise?

A

Greater volume of blood in ventricles due to increased venous return –> exerts greater pressure on arterial walls in systole

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14
Q

Why does diastolic blood pressure change after exercise?

A

Decreases due to vasodilation to the actively respiring muscles/tissues

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15
Q

Why does stroke volume change after exercise?

A

Starling’s law - greater distension of ventricular sarcomere with increased preload –> greater contraction –> greater volume of blood ejected in one beat

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16
Q

How do you calculate mean arterial blood pressure?

A

1/3(pulse pressure) + diastolic BP

OR CO x TPR

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17
Q

How may mean arterial pressure values be indicative of ischaemia?

A

MAP is considered to represent perfusion pressure, so less than 65mmHg may be indicative of ischaemia

18
Q

What are normal BP values?

A

Systolic: Below 120mmHg
Diastolic: Below 80mmHg

19
Q

What are normal HR values?

A

60-100bpm

20
Q

What are normal stroke volume values?

A

70ml

21
Q

What are normal cardiac output values?

A

4.9-5.6 L/min

22
Q

What are normal pulse pressure values?

A

40mmHg

23
Q

What are normal mean arterial pressure values?

A

65-110mmHg

24
Q

Why doesn’t MAP change after exercise?

A

Despite increased cardiac output, there is vasodilation of muscles which counteracts increased pressure

25
Q

Why does pulse pressure increase after exercise?

A

Due to increased difference in blood pressures (systolic up, diastolic down)

26
Q

What factors affect heart rate?

A

autonomic innervation, hormones, fitness and age

27
Q

What factors affect stroke volume?

A

Heart size, fitness, gender, contractility, duration of contraction, preload and afterload

28
Q

How do you calculate stroke volume?

A

EDV - ESV

29
Q

How does preload affect SV and CO?

A

Increased preload increases SV and CO

30
Q

How does afterload affect SV and CO?

A

Increased afterload (resistance) decreases SV and CO

31
Q

Outline the Frank-Starling mechanism

A

Increased venous return –> increased EDV (ventricular filling) –> increased preload –> increased myocyte stretch or sarcomere –> greater recoil –> greater ejection –> greater SV and CO

32
Q

What is a baroreceptor?

A

Stretch receptor

33
Q

Where are baroreceptors found?

A

Aorta, carotid arteries, vena cava and atria

34
Q

How do baroreceptors respond to an increase in stretch?

A

Parasympathetic stimulation increased –> decreased HR and SV –> decreased BP

35
Q

How do baroreceptors respond to a decrease in stretch

A

Parasympathetic stimulation suppressed –> increase HR and SV –> increased flow and BP

36
Q

What are chemoreceptors?

A

Receptors that respond to changes in chemicals such as pO2, pCO2, H+ and lactic acid

37
Q

Where are chemoreceptors found?

A

CNS and by baroreceptors

38
Q

How do chemoreceptors respond to an increase level of chemicals?

A

Sympathetic stimulation suppressed –> decreased HR and SV

39
Q

How do chemoreceptors respond to a decreased level of chemicals?

A

Sympathetic stimulation increased –> increased HR and SV

40
Q

What would exercise-induced hypotension indicate?

A

Coronary artery disease if drop of more than 10mmHg systolic BP during exercise

41
Q

What would exercise-induced angina indicate?

A

Angina is severe chest pain that radiates to shoulder/arm and is due to inadequate cardiac blood supply –> coronary artery disease

42
Q

Name the two main mechanisms blood flow to tissues can be increased during exercise

A

Greater stroke volume –> greater CO

Vasodilation

(YEAR 1) PBLs (29 decks)

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