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Flashcards in Physiology Deck (63):
1

what modifies respiration

the pons

2

what modifies resp rhythm

medulla

3

what are the peripheral chemoreceptors

carotid bodies
aortic bodies

4

what so the peripheral chemoreceptors do

sense tension of oxygen and carbon dioxide and [H+] in the blood

5

where are the central chemoreceptors located

medulla of the brainstem

6

how do the central chemoreceptors work

respond to [H+] of the CSF

7

what is the most potent stimulant of respiration in normal people

Arterial PCO2 acting
through the central
chemoreceptors ([H+] in CSF)

8

what receptors does hypoxia affect

peripheral chemoreceptors

9

when are the peripheral chemoreceptors stimulated in regards to hypoxia

<8.0 kPa

10

what does and does not cross the blood brain barrier

H+ doesn't

CO2 does

11

what plays a major role in adjusting for acidosis

peripheral chemoreceptors

12

what can cause acidosis

lactic acid during exercise
diabetic ketoacidosis

13

how do the peripheral chemoreceptors correct acidosis

stimulation by H+ causes hyperventilation and increases elimination of CO2 from the body

14

what does inspiration depend on

muscle contraction
- is an active process

15

what nerve controls the diaphargm

phrenic nerve
- cervical 3,4 and 5

16

what muscles are involved in inspiration

diaphragm
external intercostal muscles

17

what are muscles of active expiration

internal intercostal muscles
abdominal muscles

18

what 3 pressures are important in ventilation

atmospheric pressure
intra-alveolar pressure
intrapleural pressure

19

what are the forces keeping the alveoli open

transmural pressure gradient

pulmonary surfactant

alveolar interdependence

20

what are the forces promoting alveolar collapse

elasticity of stretched pulmonary connective tissue fibres

alveolar surface tension

21

what type of stimulation causes broncho-constriction

parasympathetic

22

what type of stimulation causes broncho-dilation

sympathetic

23

how is intrapleural pressure affected during respiration

falls during inspiration

rises during expiration

24

what is compliance

measure of effort that has to go into stretching or distending the lungs

25

what is the O2 partial pressure

60mmHg

26

what is the CO2 partial pressure

6mmHg

27

what factors can affect gas exchange

decreased surface area
increased thickness
decreased perfusion

28

what is cardiac output

The volume of blood pumped by each ventricle per minute

29

how is CO calculated

CO = SV x HR

30

what is stroke volume

the volume of blood ejected by each ventricle per heart beat”

31

how is SV calculated

End Diastolic Volume (EDV) – End Systolic Volume (ESV)

32

what can bring about changes in SV

changes in the diastolic length of myocardial fibres

33

what is preload

EDV
the volume of blood within each ventricle at the end of diastole

34

what determines EDV

venous return

35

what relationship does the Frank-Starling mechanism describe

the relationship between venous return, EDV and SV

36

what does Frank-Starling mechanism describe

the more the ventricle is filled with blood during diastole (EDV), the greater the volume of ejected blood will be during the resulting systolic contraction (SV)

37

causes of left side HF

pulmonary capillary congestion
pulmonary oedema

38

how is left sided HF caused

Stimulation of J-receptors + impaired gas exchange + decreased lung compliance

39

what is the primary factor which determines the percent saturation of Hb

Po2

40

what does anaemia lead to

impairs the o2 carrying capacity of the blood

increased CO

41

what is tidal volume

Volume of air entering or leaving lungs during a single breath

42

what is inspiratory reserve volume

Extra volume of air that can be maximally inspired over and above the typical resting tidal volume

43

what is inspiratory capacity

Maximum volume of air that can be inspired at the end of a normal quiet expiration

44

what is expiratory reserve volume

Extra volume of air that can be actively expired by maximal contraction beyond the normal volume of air after a resting tidal volume

45

what is residual volume

Minimum volume of air remaining in the lungs even after a maximal expiration

46

what is functional residual capacity

Volume of air in lungs at end of normal passive expiration (FRC = ERV + RV)

47

what is vital capacity

Maximum volume of air that can be moved out during a single breath following a maximal inspiration (VC = IRV + TV + ERV)

48

what is total lung capacity

Maximum volume of air that the lungs can hold (TLC = VC + RV)

49

what is FEV1

forced expiratory volume in one second

50

what is FVC

maximum volume that can be forcibly Expelled from the lungs following a maximum inspiration

51

what would the spirometry results be in an airway obstructive disease

FVC - low or normal
FEV1 - low
FEV1/FVC - low

52

what would the spirometry results be in a lung restrictive disease

FVC - low
FEV1 - low
FEV1/FVC - normal

53

what would the spirometry results be in a restrictive and obstructive disease

FVC - low
FEV1 - low
FEV1/FVC - low

54

what is the normal range of PaCO2

4.7-6 kPA

55

what does a high PaCO2 indicate

respiratory acidosis

56

what does a low PaCO2 indicate

respiratory alkalosis

57

how does PaCO2 play into metabolic alkalosis

body will try to compensate by raising PaCO2 (by hypoventilating)

58

how does PaCO2 play into metabolic acidosis

body will try to compensate by lowering PaCO2 (by hyperventilating)

59

what is base excess a measure of

metabolic acidosis or alkalosis

60

what does a negative BE indicate

metabolic acidosis

61

what does a positive BE indicate

metabolic alkalosis

62

how does the kidneys play into resp acidosis

try to compensate by creating metabolic alkalosis (by retaining bicarbonate)

63

how does the kidneys play into resp alkalosis

try to compensate by creating metabolic acidosis (by excreting bicarbonate)