Case 13 Flashcards

1
Q

Respiratory changes which occur during exercise?

A

Increased ventilation rate
Increased respiratory rate
Increased tidal volume
Increased O2 consumption

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2
Q

What is oxygen debt?

A

When body does intense exercise, it undergoes anaerobic respiration
This causes lactic acid build up
Oxygen debt is the amount of oxygen needed to break down the lactic acid produced by anaerobic respiration

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3
Q

What are the 2 methods of ventilatory response during exercise?

A

Increased tidal volume
Increased respiratory rate

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4
Q

Why does increased ventilation during exercise not cause ventilation perfusion mismatch?

A

Vasodilation means more blood reaches alveoli

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5
Q

What is respiratory exchange ratio?

A

Ratio between CO2 produced and O2 consumed during metabolism

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6
Q

How does respiratory exchange ratio change during exercise?

A

Higher rate of CO2 production than O2 consumption

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7
Q

What is alveolar capillary gradient?

A

Difference in O2 conc between alveoli and pulmonary capillaries

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8
Q

How does pO2 in pulmonary capillaries and alveolar capillary gradient change during exercise?

A

Decreased pO2 in capillaries
Higher alveolar - capillary gradient.. (pO2 in air in alveoli remains same)

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9
Q

What control mechanisms increase rate of ventilation during exercise?

A

-NEURAL CONTROL - peripheral receptors detect changes in blood O2 and CO2 levels, which trigger increased neural impulses to respiratory muscles
-CHEMICAL CONTROL - increased CO2 levels stimulates chemoreceptors which send signals to respiratory centres

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10
Q

Cardiovascular changes during exercise?

A

Increased heart rate
Increased stroke volume
Increased cardiac output
Peripheral vasodilation (increase blood flow to muscles)
Redistribution of blood flow (to where it is needed most)
Increased blood pressure (due to increased cardiac output)
Increased proportional O2 uptake

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11
Q

How to calculate maximal heart rate using Karvonen formula?

A

220-age

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12
Q

Explain Starling’s law ( how force of heart contraction changes with blood vol inside heart) ?

A

Greater volume of blood in heart
Increased load on muscle fibre
Meaning they stretch
This increases their contractility, so contraction force increases.

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13
Q

What is Fick equation ( calculates cardiac output) ?

A

Cardiac output = O2 consumption / (Arterial O2 content - Venous O2 content)

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14
Q

What is haemoconcentration?

A

Increase in conc of blood compentents (particularly rbc and plasma proteins)

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15
Q

Effects of training on respiration?

A

Increased maximal O2 uptake due to many factors
Increased lung capacity
Improved ventilation
Enhanced O2 transport
Reduced resp rate
Adaptions to lung and alveoli can make gas exchange more efficient

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16
Q

Effects of training on cardiovascular system?

A

Increased cardiac output (mainly due to incr hr and stroke vol)
Increased stroke vol
Reduced resting heart rate ( due to increased cardiac efficiency)
Improved performance of cardiac muscle
Enhanced blood volume
Lower blood pressure
More ‘good’ cholesterol and less ‘bad’ cholesterol in blood

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17
Q

What is hypertension?

A

High Blood pressure

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18
Q

Relationship between blood pressure, cardiac output and total peripheral resistance?

A

Blood pressure = cardiac output x total peripheral resistance

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19
Q

What is cardiac output?

A

Vol of blood expelled by heart per min

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20
Q

What is stroke volume?

A

Volume of blood expelled by heart per beat

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21
Q

Relationship between cardiac output, stroke vol and heart rate?

A

Cardiac output = stroke volume x heart rate

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22
Q

Factors which cause increased heart rate?

A

Epinephrine and Norepinephrine
Increased temp
Thyroid hormone
Caffeine

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23
Q

Factors which cause decreased heart rate?

A

Acetylcholine
Decreased temp
Intense visceral pain

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24
Q

What is visceral pain ?

A

Pain originating from internal organs

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25
Q

What is total peripheral resistance?

A

Overall resistance to blood flow encountered by systemic circulation outside of heart and lungs

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26
Q

Factors which affect total peripheral resistance?

A

Blood viscosity (minimal change)
Blood vessel length (no change)
Blood vessel radius (causes the most change)

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27
Q

How is vessel radius controlled?

A

Sympathetic nervous system

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28
Q

Vasoconstriction vs Vasodilation?

A

Vasoconstriction - decreased vessel radius
Vasodilation - increased vessel radius

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29
Q

4 types of receptors in blood?

A

Baroreceptors
Volume receptors
Chemoreceptors
Osmoreceptors

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30
Q

Describe neural control of blood pressure?

A

Uses autonomic nervous system
Directly influences heart and blood vessels
Short term mechanism of change

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31
Q

Describe numeral control of blood pressure?

A

Uses circulating factors and hormones
Directly influences heart and blood vessels, or alters blood volume
Intermediate and long term mechanism of change

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32
Q

What is vasomotor centre?

A

It regulates blood vessel diameter, so controls peripheral vascular resistance, impacting blood pressure.
It is a group of sympathetic neurones in medulla

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33
Q

What is cardiac accelerator centre?

A

Regulates heart rate and contractibility
A group of sympathetic neurones in medulla

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34
Q

What is cardiac inhibitor centre?

A

Decreases heart rate and contractibility of heart
A group of parasympathetic neurones in medulla

35
Q

What does tonically active mean?

A

Neural circuits or systems which exhibit ongoing continuous activity even without external stimuli

36
Q

What is a haemorrhage?

A

Escape of blood from blood vessels, can be internal or external (bleeeding)

37
Q

What is valsalva manoeuvre?

A

Breathing technique where you try to forcibly exhale while mouth and nose are closed.
Can be used in cardiovascular assessments, equalising pressure in middle ear (eg on plane), can relive some medical conditions

38
Q

What are catecholamines?

A

Hormones produced by adrenal gland
The main 2 are epinephrine and norepinephrine

39
Q

Function of renin angiotensin aldosterone system (RAAS)?

A

Hormone system that regulates blood pressure, fluid balance and electrolyte levels in body.

40
Q

Function of atrial natriuretic peptide (ANP)?

A

Produced and released by atrial cells in response to stretching of atrial walls
This happens due to incr blood vol or pressure
Causes vasodilation, sodium and water excretion and inhibition of aldosterone
This decreases blood vol and pressure

41
Q

What is aldosterone?

A

Hormone which promotes sodium and water retention

42
Q

Function of anti-diuretic hormone (ADH)?

A

Produced in hypothalamus and released by posterior pituitary gland
Causes water re-absorption and vascoconstriciton
Prevents excessive water loss from body and increases blood pressure

43
Q

Why does blood pressure fluctuate throughout the day?

A

Posture changes
Physical activity
Changes in environment

44
Q

Describe the effect of potassium on vascular smooth muscle?

A

1) K channels open, so potassium leaves cell
2) Smooth muscle cells are hyper polarised
3) This hyperpolarisation inhibits smooth muscle contraction, causing vasodilation

45
Q

Give 3 examples of types of potassium channels?

A

ATP sensitive (KATP) - open/close based on changes in ATP conc
Voltage gated (Kv) - open/close based on changes in voltage
Calcium activated (Kca) - open/close based on changes in calcium

46
Q

What are calcium sparks??

A

Localised increase in calcium within arterial smooth muscle cells
(Calcium channels in sarcoplasmic reticulum open, releasing calcium)

47
Q

How do calcium sparks cause muscle relaxation?

A

1) Activate calcium sensitive potassium channels
2) Potasssium leaves cell
3) Membrane becomes hyper polarised
4) Voltage dependant calcium channels inactivated
5) Free cytoplasmic calcium reduced
6) Muscles relax

48
Q

Describe response of vascular smooth muscle to pressure?

A

1) Blood pressure increases and stretch sensitive baro receptors detect change
2) These send signals to smooth muscle cells in vessel walls, triggering intracellular pathways, leading to contraction.

49
Q

Describe potential link between blood pressure, cerebral flow and Alzheimer’s disease?

A

High blood pressure causes reduced cerebral flow and increased vascular resistance, which can contribute to progression of Alzheimer’s.

50
Q

Aims of hypertensive drugs?

A

Reduce blood pressure

51
Q

Methods of reducing blood pressure?

A

Reduce heart rate
Reduce stroke volume
Reduce plasma volume (by acting on kidney to reduce water re-absorption)
…reducing cardiac output
Dilating arterioles (to reduce peripheral resistance)

52
Q

Function of B adrenergic receptor blockers (B blockers)?

A

Act on heart to block beta receptors to reduce cardiac output and inhibit renin secretion in kidney.

53
Q

Function of renin in kidney?

A

Regulates fluid balance in body

54
Q

Function of diuretics?

A

Act on kidney to inhibit salt and water reabsorbtion, reducing plasma volume

55
Q

Example of a diuretic used for BP control?

A

Thiazide Diuretics

56
Q

Function of vasodilators?

A

Dilate blood vessels (to lower peripheral resistance)

57
Q

2 examples of vasodilators used for hypertension?

A

Calcium antagonists
A1 adrenoreceptor blockers

58
Q

Function of inhibitors of renin-angiotensin-aldosterone axis?

A

Inhibits production of or effect of vasoconstrictor and promotes salt retention.
This reduces plasma volume

59
Q

Examples of inhibitors of renin-angiotensin-aldosterone axis?

A

Angiotensin converting enzyme (ACE) inhibitors
Angiotensin receptor antagonists (ARBs)

60
Q

How can hypertension by managed by changes in behaviour?

A

-Healthy diet
-Regular exercise
-Weight management
-Smoking cessation
-Stress management
-Limited caffeine intake
-Getting adequate sleep
-Regular blood pressure monitoring

61
Q

Describe structure of artery?

A

Thick muscular walls

62
Q

Describe structure of vein?

A

Thinner less muscular walls
Contains valves
Larger lumen

63
Q

Describe structure of lymph vessels?

A

Thin walls
Contains valves

64
Q

What is the systemic circulatory system?

A

Transports oxygenated blood from heart to body’s tissues and returns deoxygenated blood back to heart

65
Q

What is pulmonary circulatory system?

A

Transports deoxygenated blood from heart to lungs for oxygenation and returns oxygenated blood back to heart

66
Q

Name 5 different types of blood vessel?

A

Arteries
Arterioles
Capillaries
Venules
Veins

67
Q

What are arteries?

A

Carry oxygenated blood from heart to various tissues and organs

68
Q

What are arterioles?

A

Branches of arteries which divide into capillaries

69
Q

What are capillaries?

A

Thin walled blood vessels which exchange gas and nutrients with blood and tissues

70
Q

What are venules?

A

Collect blood from capillaries and merge to form veins

71
Q

What are veins?

A

Carry deoxygenated blood back to heart

72
Q

What is peripheral oedema?

A

Abnormal accumulation of fluid in the tissues - typically in legs, ankles or feet
(Swelling)

73
Q

What is hydrostatic pressure/blood pressure?

A

Pressure exerted by blood against walls of capillaries
Pushes fluid out of capillaries into the interstitial space and tissues

74
Q

What is oncotic pressure?

A

Osmotic pressure exerted by proteins in blood plasma
This pulls fluid from interstitial space back into capillaries

75
Q

What is net filtration pressure?

A

Balance of hydrostatic and oncotic pressure
Force responsible for moving fluid in/out of capillaries

76
Q

Give ways how a change in net filtration pressure can occur?

A

Increased capillary hydrostatic pressure
Decreased plasma oncotic pressure
Increased capillary permeability
Obstruction of lymphatic drainage

77
Q

Describe the renin-angiotensin-aldosterone axis?

A

Regulates blood pressure and fluid balance
-Blood pressure drops, renin released
-Renin converts angiotensinogen to angiotensin I
-Angiotensin - converting - enzyme (ACE) converts angiotensin I into angiotensin II
-Angiotensin II causes vasodilation, stimulates release of aldosterone and stimulates release of ADH
-Aldosterone promotes sodium and water retention (raising blood pressure)

78
Q

Describe mechanism of action of ADH (Antidiuretic hormone)?

A

Released by posterior pituitary gland in response to changes in blood osmolarity or blood volume
Acts on kidneys to increase water resorption to maintain blood vol and pressure
Also causes vasoconstriction - incr blood pressure

79
Q

Describe mechanism of action of natriuretic peptides?

A

Released by heart in response to increased blood volume and stretching on heart muscle
Promote vasodilation and increase excretion of sodium and water by kidneys
Inhibit release of renin and aldosterone
Decreases blood pressure and blood volume

80
Q

How does sympathetic nervous system control cardiac muscle function?

A
  • Sympathetic nervous system releases norepinephrine and low amount of epinephrine which bind to and activate Bea adrenergic receptors
  • This increases heart rate, increases contractability and accelerates electrical conduction through heart
  • This increases cardiac output, preparing heart for physical activity or stress
    SYMPATHETIC - FIGHT OR FLIGHT
81
Q
  • How does parasympathetic nervous system control cardiac muscle function?
A
  • Parasympathetic nervous system releases acetylcholine which binds to receptors on cardiac muscle cells
  • This slows heart rate, decreases contractility and delays electrical conduction through heart
  • This promotes rest and recovery, conserves energy and is used in periods of low demand
    PARASYMPATHETIC - REST AND DIGEST
82
Q

What is vascular tone?

A

Amount of constriction or dilation of blood vessels

83
Q

How does sympathetic nervous system control vascular tone?

A
  • Sympathetic nervous system releases norepinephrine onto smooth muscle cells in blood vessels which binds to and activates alpha adrenergic receptors
  • This causes vascoconstriction and increased vascular resistance
  • This is used to redirect blood flow to more important areas
84
Q

The effect of smoking on cardiovascular system?

A
  • Increased blood pressure
  • Damage to endothelium of blood vessels
  • Increased heart rate and arrhythmias
  • Reduced oxygen delivery
  • Increased blood clotting
  • Exacerbation of existing cardiovascular conditions