SBA formative Flashcards
most important stimulus controlling level of ventilation at rest
low CSF pH on central chemoreceptors
majority of CO2 transported from tissues to lungs by blood as?
bicarb ions (70%) carbamino compounds (20%) dissolved CO2 (10%)
what factor has greatest effect in increasing oxygen delivery to muscles during exercise
large drop in p02 in tissues
flow volume loop for restrictive disease
tall and narrow
FVC dec!
normal slope expiratory part as there’s no obstruction
quiet expiration involves which muscles
relax of all respiratory muscles
quiet inspiration involves which muscles
contract diaphragm and external intercostal
forced expiration muscle
internal intercostals
+more ?
forced inspiration
SCM
scalene
+more
asthma triggers
exercise drugs (NSAIDs/B blockers) chemicals (varnish/paint) emotional distress allergens cold air car exhaust fumes
accessory muscles of respiration in neck
SCM scalee trapezius pectoralis major serrates anterior
cause for hypoaemia with pneumonia
VQ mismatch
how does septic shock affect acid base balance
lactic acidosis
low BP, tachycardia
what causes hypoxaemia in RDS of newborn
VQ mismatch
poorly ventilated alveoli secondary to inc surface tension > partial collapse but still perfused
and
poor compliance > hypoventilation of lungs
alkalosis effect on Hb curve and oxygen delivery to tissue
shift LEFT > less dissociation of oxygen in tissues
adaptations to live at high altitude
- inc 2,3 DPG
- inc tissue capillary density
- inc Hb secondary to hypoxia stimulating EPO release by kidneys
how does bronchial carcinoma cause left vocal cord paralysis
- left recurrent laryngeal nerve descends into thorax
> winds around aorta and travels up to larynx - damaged in thorax by bronchial carcinoma
describe cough reflex
- deep inspiration followed by closure of glottis
- strong contraction of expiratory muscles
- sudden opening of glottis > explosive discharge of air
why is cough less effective with left vocal cord paralysis
glottis can’t be closed properly
muscle contraction can’t build up sufficient intrapulmonary pressure for cough
complications of spread of bronchial tumour
- paralysis hemidiaphgram (phrenic nerve)
- pericardial effusion (spread to pericardium)
- lung collapse due to obstruction of bronchus
- pneumonia distal to partially obstructed bronchus
what’s the reason for the pleural pressure
balance at rest between inward elastic recoil and outward recoil of chest wall
why does the lung collapse in pneumothorax
pleural seal broken
inward elastic recoil no longer balanced by chest recoil
collapse towards hilum
treatment for large pneumothorax
chest drain connected to underwater seal > air drained out, lung expand
why does O2 treatment for COPD cause increased hypercapnia
with oxygen there is reduced pulmonary hypoxia induced vasoconstriction in poorly ventilated alveoli
> diverts blood away from better ventilated alveoli
> worsens VQ mismatch
how does Haldane effect result in hypercapnia for COPD its treated with oxygen
oxygenated Hb carries less CO2
oxygen therapy causes cO2 release in blood from the increased oxygenated Hb
pleural effusion
homogenous dense opacity
exudate vs transudate
ex- more protein
how does congestive heart failure cause pleural effusion
inc hydrostatic pressure at venous end of capillary of parietal pleura
more fluid leaving capillary causing pleural effusion
