respiration Flashcards
what is meant by ‘partial pressure’?
the pressure exerted by a particular gas in a mixture of gases
what is the respiration quotient?
RQ= volume of CO2 produced/volume of oxygen consumed
outline the events of inspiration/inhalation
1) diaphragm contracts and moves down
2) chest expands, ribcage moves up and thoracic cavity is enlarged
3) pressure in the lungs decreases and air fills them
outline the events of expiration/exhalation
1) diaphragm relaxes and moves up
2) chest expands and ribcage moves down
3) thoracic volume restored by elastic recoil of the diaphragm
what is the relationship between airway resistance and lung volume?
inversely proportional
is asthma an obstructive or restrictive deficit?
obstructive
is pneumothorax an obstructive or restrictive deficit?
restrictive
explain what happens during an asthma attack
increase in airway resistance as bronchial smooth muscle contracts
what is meant by surface tension?
the pressure exerted on the alveoli to make them collapse
what is FVC?
total volume of air that can be breathed out with max effort in one breath
what is FEV?
how much air is breathed out in the first second
how can FEV and FVC be used in diagnosis?
obstructive deficits: FEV/FVC = <7, FEV <80%
restrictive deficits: FEV/FVC = normal, FEV <80%
what do pulmonary ARTERIES carry?
deoxygenated blood to right atrium
what do pulmonary VEINS carry?
oxygenated blood to the left atrium
what does p50 represent?
when Hb is 50% saturated/venous pO2 in exercise
which conditions cause affinity of Hb for oxygen to increase?
high pH
decrease in temp
decrease in pCO2
what does the Bohr effect refer to?
the effects of low pH and high pCO2 in causing a decrease in affinity of Hb for O2, resulting in release of O2 into oxygen poor tissues
what is the pO2 and pCO2 in the pulmonary veins/systemic arteries?
pO2 100 mmHg
pCO2 40 mmHg
what is the pO2 and pCO2 in the pulmonary arteries/systemic veins?
pO2 40mmHg
pCO2 46 mmHg
by which methods is CO2 transported?
8% in plasma
80% carried as bicarbonate via carbonic anhydrase
12% binds to carbamino compounds such as Hb
where is CO2 transported after it leaves the cell?
right atrium via systemic veins, then to alveoli by pulmonary arteries
which nerve controls inspiration?
phrenic nerve; provides nerve supply to the diaphragm
where are the respiratory receptors responsible for the control of rate and depth located?
brainstem and medulla
name the effects of high altitude
pO2 decreases
Hb less saturated
tissues receive less O2
respiration cannot provide sufficient ATP
increase in cardiac output and ventilation
