ventilation continued

Question 1

poiseulle’s law

Answer 1

R = 8nl/pi(r)to power of four

Question 2

boyle’s law

Answer 2

Pgas (proportion symbol) 1/Vgas

Question 3

alveolar ventilation

Answer 3

the volume of air reaching the respiratory zone per minute

Question 4

pulmonary ventilation

Answer 4

is the air flowing in and out of the lungs

Question 5

how do lung volumes change in obstructive lungs

Answer 5

residual air increase - bronchoconstriction and elastic properties of parenchyma lost
IRV, ERV and TV decreased
airflow out of the lungs obstructed
COPD, emphysema, bronchitis, asthma`

Question 6

how do lung volumes change in restrictive lungs

Answer 6

everything decreased
inflation and deflation of the wall restricted
lungs operate at lower volumes
lung fibrosis, interstitial lung disease, obesity, neuromuscular disease
obesity - resp muscles a=have to work harder to move weight inc diaphragm - weight of abdomen

Question 7

alveolar dead space `

Answer 7

capacity of airwasy that should be able to undertake gas exchange but cannot - eg hypopervused alveoli
non-perfused parenchyma  
no GE 
0ml in adult
lower generations to generation 23 `

Question 8

anatomical dead space

Answer 8

capacity of airways incapable of gas exchange
conducting zone
upper branch
16generations
typically 150ml at func residual capacity

Question 9

physiological dead space

Answer 9

equivalent to the sum of alveolar and anatomical dead space

Question 10

changing dead space

Answer 10

smoking increases it - not reversible
tracheostomy/cricothyrotomy - reduction in dead space
anaesthetic tubing/snorkelling/ventilator increase dead space from mouth

Question 11

effect of increasing ventilation on the circulation

Answer 11

alveoli bigger = compression of the capillary
extraalveolar vessels open up - increase perfusion into the chest
alveolar capillaries compressed
high vascular resistance `

Question 12

effect of expiration on vascular resistance

Answer 12

+ve intrathoracic pressure
alveola vessels distend closer to alveoli
thorax vol has decreased - compress vessels associated with mechanical structures
increased vascular resistance

Question 13

Edit Delete

relationship between vascular resistance and lung volume

Answer 13

they’re proportional

Question 14

Ventilation and perfusion in the lungs

Answer 14

because of gravity more pressure needed to ventilate the apex
at apex Ppl higher = greater transmural pressure = alveoli large and less compliant = less vent
at base Ppl less -ve = smaller transmural pressure = alveoli smaller = more vent
apex - lower intravascular pressyre - gravity = less recruitment, greater resistance = lower flow rate of blldo
base = higher intravacular pressure - gravity, more recruitment, less resistance, higher flow rate = more perfusion at the base
base more willing to be ventilated and perfused

Question 15

effect of exercise on perfusion in the lung

Answer 15

the under perfused vessels at the apex of the lung are recruited meaning the pressure doesn’t increase

Question 16

cause of hypoxaemia in lung disease

Answer 16

V/Q mismatching

blood not reach ventilated alveoli GE cant occur