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Physiology Year 1 > Week 2 > Flashcards

Week 2 Flashcards

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1
Q

How thick is the alveolar wall?

A

Between 0.2 and 2.5 microns thick

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2
Q

what percentage of the atmostphere is oxygen?

A

20.93

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3
Q

what percentage of the atmoshere is carbon dioxide?

A

0.03

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4
Q

what percentage of the atmosphere is oxygen?

A

20.93

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5
Q

what is dalton’s law?

A

the total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture

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6
Q

how to work out partial pressure

A

percentage of gas in atmosphere x total pressure (760mmHg at sea level)

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7
Q

what is henry’s law?

A

gases dissolve in iquids in proportion to partial pressure

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8
Q

gases dissolve in liquids but depend on specific things incuding partial pressure - what else?

A

specific fluid medium, temperature.
solubility of a substance in blood is constant at a given temperature

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9
Q

what is the partial pressure of oxygen at the alveolus?

A

105

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10
Q

what is the partial pressure of oxygen at the capillaries (venous blood)

A

40

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11
Q

what is the percenage of carbon dioxide at the alveolus?

A

40

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12
Q

what is the partial pressure of carbon dioxide at the capillaries (venous blood)?

A

45

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13
Q

what is the most important factor for determining gas exchange?

A

partial pressure gradient

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14
Q

what is the a.v. O2 difference?

A

the difference between the arterial and venous oxygen levels.

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15
Q

what does the a.v. O2 difference impact?

A

the ability of your muscles to extract oxygen and use it,
as extraction increases, venous oxygen level decreases and a.v. O2 difference increases

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16
Q

what is the arterial oxygen content?

A

20/100ml blood

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17
Q

what is the venous oxygen content at rest?

A

15-16ml/100ml

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18
Q

what is the venous oxyge content during exercise?

A

4-5ml/100ml blood

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19
Q

what percentage of oxygen is bound to haemoglobin in the blood?

A

98

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20
Q

how many oxygen molecules does a fully saturated haeoglobin molecule carry?

A

4

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21
Q

is oxygen or carbon dioxide more solule?

A

carbon dioxide

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22
Q

how does a small decrease in the partial pressure of oxygen affect oxygen saturation?

A

fairly significant decrease in saturation

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23
Q

how do temperature and partial pressure of CO2 affect oxygen deloading?

A

oxygen is offloaded at a higher partial pressure

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24
Q

what is the bohr shift?

A

the graph (of PO2 and haemoglobin saturation) shifts to the right when pCO2 and temperature increase

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25
How is CO2 carried in the blood?
as bicarbonate ions (70%), dissolved in plasma (10%), bound to harmoglobin as carbaminohaemoglobin (20%).
26
what is the importance of carrying carbon dioxde as bicarbonate ions?
helps control our acid-base balance
27
how do bicarbonate ions help control the acid-base balance?
CO2 and water form carbonic acid (H2CO3), this occurs in red blood cells and is catalysed by carbonic anhydrase H2CO3 dissociated into bicarbonate ions and acid (HCO3 and H+). The H+ binds to haemoglobin, acting as a buffer and triggering the bohr effect
28
How does more CO2 mean O2 offloaded at a higher partial pressure?
More CO2 = more carbonic acid, so more H and then more H bound to haemoglobin so more O2 offloaded
29
what is cardiac output?
volume of blood ejected by the heart in one minute Carduac output = HR x SV
30
What is cardiac output at rest?
HR = 70bpm, SV = 70ml, cardiac output = approx 5litres
31
what is stroke volume?
volume of blood ejected from the heart each beat
32
what is stroke volume during maximal exercie?
150-160ml
33
what is stroke volume dependent on?
end diastolic volume (preload) strenght of the ventricular contraction (contractility) average aortic blood pressure (afterload)
34
what is frank stirling law?
SV increases in response to an increase in EDV due to a stretch in the ventricles which causes greater contraction, depends on venous return.
35
what influences venous return?
how much your muscles act as a respiratory pump, valves in veins and vasoconstriction.
36
how is the respiratory pump created during exericse?
you are squeezing your abdominal muscles creating high pressure, but thoracic cavity is expanding creating low pressure.
37
what is the fick equation?
cardiac output = volume oxygen consumption in lungs / a.v. O2 difference
38
what would the most accurate measure of a.v. O2 difference be?
measurement from pulmonary artery (venous system) and left atrium or aorta (aoritc system). this would be impossible, so peripheral artery is used instead e.g. wrist.
39
what is extrinsic innervation?
autonomic control of the myocardium (heart)
40
where does the parasympathetic impulse travel down?
vagus nerve
41
what does the vagus nerve do? - consequential impact
release a neurotransmitter acetylcholine, affecteng the SA node, AV node and atrial myocardium. results in SA depolarisation (bradycardia) - decreasing heart rate.
42
where does the sympathetic impulse travel down?
cardiac acceleratory nerves
43
what does the sympathetic impulse cause?
adrenal medulla to release catecholamines (adrenaline and noradrenaline). affects SA, AV nad atrial and ventricular myocardium - results in increase in depolarisation (tachycardia), increase in SV, HR.
44
what is the positive ionotropic effect?
increase in contractility
45
what is anticipatory rise?
an increase in heart rate before exercise even if resting, in preparation for exercise.
46
why does anticipatory rise occur?
central command withdraws parasympathetic impulses until HR is about 100bpm. further increase is then due to symapthetic impulses.
47
why does HR decrease rapidly after exercise?
parasympathetic system is started again and muscle proprioceptors are not feeding back. mrore gradual as sympathetic system still involved not stopped completely
48
tachycardia vs bradycardia
tachycardia - RHR above 100bpm, bradycardia - RHR below 60bpm
49
why is RHR important?
for every increase of 10bpm in RHR there is a 9% increase risk of mortality and an 8% increase in risk of cardiovascular mortality.
50
what is heart rate variability?
looks at ratio of sympathetic to parasympathetic nervous system.
51
how is heart rate variability used?
in recovery - as an indicator of possible further arrests in sport - overtraining usually causes a drop in HR variability
52
what is a normal heart rate recovery?
greater than 22bpm.
53
what is an abormal heart rate recovery?
anything less than 12bpm.
54
how is heart rate used to set training zones?
of max HR maximum - 90-100% hard - 80-90% moderate - 70-80% light - 60-70% very light - 50-60%
55
what is the most accurate way to get a max heart rate value?
VO2 max test
56
P wave
atrial systole and ventricular diasole continues
57
QRS complex
ventricular systole and atrial diastole start
58
T wave
atrial diastole continue, ventricular diastole starts at end of wave
59
how to identify angina from an ECG
a fall in hte line between S and T
60
what does an echocardiogram look at?
mechanical control of the heart - wall thickness, valve function ad ejection fraction (how much blood is ejecting)
61
systole
heart contracting
62
diastole
heart relaxing
63
pulse pressure
systolic blood pressure - diastolic blood pressure issues if over 70 (wide)
64
mean arterial pressure
diastolic blood pressure + (pulse pressure/3).
65
what looks at internal and energy demands placed on the heart?
rate pressure produced = systolic blood pressure x heart rate
66
blood pressure equation
cadiac output x peripheral resistance
67
what affects stroke volume?
venous return, muscle pump, respiratory pump, valves, frank stirling law, blood volume
68
what affects heart rate?
sypathetic vs parasympathetic receptors feeding into the control centre, temperature, adrenaline
69
what affects peripheral resistance?
vessal diameter, blood viscosity, total vessel length
70
what is the RAAS system?
renin-angiotensin-aldosterone system
71
what does the RAAS system reduce?
blood pressure
72
describe the RAAS system
kidneys notice drop in blood pressure and release renin, liver releases angiotensin. renin converts a to A I, angiotensin converting enzyme is released converting A I into A II.
73
How does angiotensin II reduce blood [ressure?
increasing sympathetic activity - increasing HR Kidneys retain more salt and increase K excretion, increases water retention >> increasing blood volume and pressure vasoconstriction of arterioles pituitary gland releases ADH
74
What can be taken if RAAS system is faulty?
ACE (angiotensin converting enzyme) inhibitors so the angiotensin I is not converted.
75
how does exercise effect blood vessels?
endothelial cells in the lining release nitric ocide, a vasodilator, increasing the diameter of the lumen, decreasing blood pressure.
76
how is blood pressure reduced during exercise?
nitric oxide - vasodilatory Atrial natriuretic peptide (ANP) reduces renin release hypothalamus and pituitary reduce release of ADH drop in aldosterone from adrenal cortex, stopping absorption of water

Physiology Year 1 (4 decks)

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