physiology supplementary

Question 1

boyle’s law

Answer 1

pressure is inversely proportional to volume

Question 2

how are lungs linked to thorax (2 ways)

Answer 2

intrapleual fluid cohesiveness negative intrapleural pressure (lungs push out and thorax pushes in )

Question 3

what is alveolar surface tension

Answer 3

attraction between water molecules at liquid air surface, resist lung stretching

Question 4

laplaces law

Answer 4

P = (2T) / r

Question 5

what does laplaces law mean

Answer 5

smaller alveoli have a greater tendency to collapse

Question 6

how are smaller alveolis prevented from collapse

Answer 6

surfactant reduces surface tension

Question 7

alveoli interdependence

Answer 7

if one alveoli collapses the others save it

Question 8

what is the normal inspiratory capacity

Answer 8

females - 3500ml males - 4500 ml

Question 9

what is FRC

Answer 9

volume of air in lungs at the end of a normal passive expiration. ERV+RV

Question 10

what is IC

Answer 10

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

TV + IRV

Question 11

Answer 11

Question 12

when does residual volume inc

Answer 12

when the elastic recoil of the lungs is lost eg emphysema

Question 13

can total lung volume be measured by spirometry?

Answer 13

no because RV cant be measured by spirometry

Question 14

what does dec pulmonary compliance cause

Answer 14

SOB on exertion

Question 15

what is dec pulmonary compliance seen in

Answer 15

restrictive diseases

Question 16

why is alveolar ventilation less than pulmonary ventilation

Answer 16

because of anatomical dead space

Question 17

define pulmonary ventilation

Answer 17

vol of air breathed in and out per minute

Question 18

define alveolar ventilation

Answer 18

vol of air exchanged between the atmosphere and the alveoli per minute

Question 19

what is physiological dead space

Answer 19

anatomical + alveolar dead space

Question 20

what is alveolar dead space

Answer 20

ventilated alveoli that are not adequately perfused with blood

Question 21

daltons law

Answer 21

total pressure exerted by a gaseous mixture is the sum of the partial pressures of each individual component in the gas mixture

Question 22

compare the diffusion coefficient of CO2 to O2

Answer 22

CO2 is 20x more than O2

Question 23

ficks law

Answer 23

The amount of gas that moves across a sheet of tissue in unit time is proportional to the area of the sheet but inversely proportional to its thickness

Question 24

henrys law

Answer 24

The amount of a given gas dissolve in a given type and volume of liquid (e.g. blood) at a constant temperature is: proportional to the partial pressure of the gas in equilibrium with the liquid

Question 25

how is most O2 found in the body

Answer 25

bound to Hb

Question 26

what is the primary factor that determines the percent saturation of Hb with O2

Answer 26

PO2

Question 27

how does anaemia effect O2 conc of bood

Answer 27

dec Hb concentration and dec O2 conc of blood

Question 28

describe the oxygen Hb binding curve

Answer 28

sigmoidal

Question 29

what is the taut form of Hb

Answer 29

deoxyHb

Question 30

what is the relaxed form of Hb

Answer 30

oxyHb

Question 31

what is the Bohr effect

Answer 31

The Bohr Effect Facilitates the Removal of O2 from Haemoglobin at Tissue Level by Shifting the O2-Hb Dissociation Curve to the Right

Question 32

foetal Hb subunits

Answer 32

2 alpha and 2 gamma

Question 33

compare foetal Hb affinity or Hb

Answer 33

higher than normal - curve is shifted left

Question 34

when if foetal Hb replaced by adult Hb

Answer 34

a few months after birth

Question 35

where is myoglobin present

Answer 35

skeletal and cardiac muscle

Question 36

ratio of haem molecule to myoglobin binding

Answer 36

1:1

Question 37

what does the presence of myoglobin in the blood indicate

Answer 37

muscle damage

Question 38

what does myoglobin provide

Answer 38

a short term storage for O2 in anaerobic conditions

Question 39

describe the myoglobin curve and what it means

Answer 39

hyperbolic - myoglobin releases O2 at a very low PO2

Question 40

how is the majority of CO2 transported

Answer 40

as bicarbonate

Question 41

what helps the formation of bicarbonate from CO2 and H2O and where does this occur

Answer 41

carbonic anhydrase, occurs in RBC

Question 42

describe the haldane effect

Answer 42

removing oxygen from Hb inc the ability of Hb to pick up CO and H ions

Question 43

what is the point of the Bohr and haldane effect

Answer 43

O2 liberation and uptake of CO and H ions at tissues

Question 44

what generates the breathing rhythm

Answer 44

pre botzinger complex

Question 45

how does normal inspiration come about

Answer 45

firing of the dorsal respiratory group neurones

Question 46

how does passive expiration come about

Answer 46

the dorsal neurones cease firing

Question 47

how does active expiration come about

Answer 47

ventral neurones fire - excite the internal intercostals and abdominals etc

Question 48

where can the breathing rhythm be modified

Answer 48

pons - pneumotaxic centre

Question 49

what does the PC do

Answer 49

inhibit inspiration

Question 50

wha would happen without PC

Answer 50

apneusis

Question 51

when is the PC stimulated

Answer 51

when the dorsal neurones fire (inspiration)

Question 52

what does the apneustic centre do

Answer 52

prolong inspiration

Question 53

describe general breathing rhythm control

Answer 53

generated in the medulla and modified in the pons

Question 54

which receptors guard against hyperinflation

Answer 54

pulmonary stretch receptors - Hering Breuer reflex

Question 55

what are the juxtapulmonary receptors stimulated by

Answer 55

pulmonary congestion and oedema (LVF), also pulmonary emboli cause rapid shallow breathing

Question 56

what TV will the pulmonary stretch receptors be activated at

Answer 56

\>1 l

Question 57

which receptors contribute to the inc ventilation during exercise

Answer 57

joint

Question 58

what do chemoreceptors sense

Answer 58

the value of gas tensions

Question 59

what do peripheral chemoreceptors sense

Answer 59

oxygen and CO2 and H conc in blood

Question 60

what do central chemoreceptors respond to

Answer 60

H conc of CSF

Question 61

how is CSF separated from the blood

Answer 61

blood brain barrier

Question 62

what can cross the BBB

Answer 62

CO2 NOT H and HCO3

Question 63

when is the hypoxic drive important

Answer 63

at high altitudes and with COPD

Question 64

when is the hypoxic drive stimulated

Answer 64

PO2 \<8kPa

Question 65

what is hypoxia at high altitudes stimulated by

Answer 65

dec partial pressure of insired oxygen

Question 66

what is the acute reponse to hypoxia at high altitudes

Answer 66

hyperventilation and inc CO

Question 67

what are the symptoms of acute mountain sickness

Answer 67

headache, fatigue, nausea, TACHYCARDIA, dizziness, sleep disturbance, exhaustion, shortness of breath, unconsciousness

Question 68

what does the chronic adaption to hypoxia involve

Answer 68

inc RBC production, inc 23 DPG production, inc number of capillaries, inc no of mitochondria and kidneys conserve acid and METABOLIC ACIDOSIS

Question 69

what is inc RBC production called

Answer 69

polycythaemia

Question 70

how do the peripheral chemoreceptors adjust for acidosis

Answer 70

sense H ions and cause hyperventilation and inc elimination of CO2 from the body

Question 71

what is diabetic ketoacidosis

Answer 71

Hyperventilation with a severe metabolic acidosis.