SBA formative

Question 1

most important stimulus controlling level of ventilation at rest

Answer 1

low CSF pH on central chemoreceptors

Question 2

majority of CO2 transported from tissues to lungs by blood as?

Answer 2

bicarb ions (70%)
carbamino compounds (20%)
dissolved CO2 (10%)

Question 3

what factor has greatest effect in increasing oxygen delivery to muscles during exercise

Answer 3

large drop in p02 in tissues

Question 4

flow volume loop for restrictive disease

Answer 4

tall and narrow
FVC dec!
normal slope expiratory part as there’s no obstruction

Question 5

quiet expiration involves which muscles

Answer 5

relax of all respiratory muscles

Question 6

quiet inspiration involves which muscles

Answer 6

contract diaphragm and external intercostal

Question 7

forced expiration muscle

Answer 7

internal intercostals

+more ?

Question 8

forced inspiration

Answer 8

SCM
scalene

+more

Question 9

asthma triggers

Answer 9

exercise
drugs (NSAIDs/B blockers)
chemicals (varnish/paint)
emotional distress
allergens
cold air
car exhaust fumes

Question 10

accessory muscles of respiration in neck

Answer 10

SCM
scalee
trapezius
pectoralis major
serrates anterior

Question 11

cause for hypoaemia with pneumonia

Answer 11

VQ mismatch

Question 12

how does septic shock affect acid base balance

Answer 12

lactic acidosis

low BP, tachycardia

Question 13

what causes hypoxaemia in RDS of newborn

Answer 13

VQ mismatch
poorly ventilated alveoli secondary to inc surface tension > partial collapse but still perfused

and

poor compliance > hypoventilation of lungs

Question 14

alkalosis effect on Hb curve and oxygen delivery to tissue

Answer 14

shift LEFT > less dissociation of oxygen in tissues

Question 15

adaptations to live at high altitude

Answer 15

• inc 2,3 DPG
• inc tissue capillary density
• inc Hb secondary to hypoxia stimulating EPO release by kidneys

Question 16

how does bronchial carcinoma cause left vocal cord paralysis

Answer 16

• left recurrent laryngeal nerve descends into thorax
  > winds around aorta and travels up to larynx
• damaged in thorax by bronchial carcinoma

Question 17

describe cough reflex

Answer 17

• deep inspiration followed by closure of glottis
• strong contraction of expiratory muscles
• sudden opening of glottis > explosive discharge of air

Question 18

why is cough less effective with left vocal cord paralysis

Answer 18

glottis can’t be closed properly

muscle contraction can’t build up sufficient intrapulmonary pressure for cough

Question 19

complications of spread of bronchial tumour

Answer 19

• paralysis hemidiaphgram (phrenic nerve)
• pericardial effusion (spread to pericardium)
• lung collapse due to obstruction of bronchus
• pneumonia distal to partially obstructed bronchus

Question 20

what’s the reason for the pleural pressure

Answer 20

balance at rest between inward elastic recoil and outward recoil of chest wall

Question 21

why does the lung collapse in pneumothorax

Answer 21

pleural seal broken
inward elastic recoil no longer balanced by chest recoil
collapse towards hilum

Question 22

treatment for large pneumothorax

Answer 22

chest drain connected to underwater seal > air drained out, lung expand

Question 23

why does O2 treatment for COPD cause increased hypercapnia

Answer 23

with oxygen there is reduced pulmonary hypoxia induced vasoconstriction in poorly ventilated alveoli
> diverts blood away from better ventilated alveoli
> worsens VQ mismatch

Question 24

how does Haldane effect result in hypercapnia for COPD its treated with oxygen

Answer 24

oxygenated Hb carries less CO2

oxygen therapy causes cO2 release in blood from the increased oxygenated Hb

Question 25

pleural effusion

Answer 25

homogenous dense opacity

Question 26

exudate vs transudate

Answer 26

ex- more protein

Question 27

how does congestive heart failure cause pleural effusion

Answer 27

inc hydrostatic pressure at venous end of capillary of parietal pleura

more fluid leaving capillary causing pleural effusion