physiology Flashcards
internal respiration
intracellular mechanisms which consumes oxygen to produce carbon dioxide
external respiration
ventilation
exchange in lungs
transport
exchange in tissues
Boyles law
at any constant temperature the pressure exerted by a gas varies inversely with the volume of the gas. as the volume of a gas increases the pressure exerted by the gas decreases
forced vital capacity
maximum volume of air that can be forcibly expelled from lungs following a maximum inspiration
forced expiratory volume in one second
volume of air that can be expired the first second of FVC
FEV1/FVC
more than 70%
obstructive lung disease
lower FEV1
low FEV1/FVC
restrictive lung disease
lower FVC and FEV1
normal FEV1/FVC
dynamic airway compression
is the rising pleural pressure during active expiration compresses the alveoli and airways
makes active expiration more difficult in patients with airway obstruction
pulmonary compliance
measure of effort put into stretching or distending the lungs
pulmonary ventilation
tidal volume x respiratory rate
volume of air breathed in and out per minute
alveolar ventilation
(tidal volume - dead space) x respiratory rate
volume of air exchange between atmosphere and alveolar per minute
ventilation perfusion
mismatch is resolved by smooth muscle action of airways and arterioles
alveolar dead space
ventilated alveoli that are not perfused
rate of gas exchange is influenced by
partial pressure gradient of oxygen and carbon dioxide
diffusion coefficient for oxygen and carbon dioxide
surface area if alveolar membrane
thickness of alveolar membrane
Dalton’s law of partial pressures
the total pressure exerted by gaseous mixture is the sum of the partial pressures of each component
Fick’s law of diffusion
amount of gas that moves across a sheet of tissue in unit time is proportional to the area of the sheet and inversely proportional to its thickness
Henry’s law
amount of a given gas dissolve in a given type and volume of liquid at a constant temperature proportional to the partial pressure of the gas in equilibrium with the liquid
oxygen delivery index
oxygen content of arterial blood x cardiac index
means of carbon dioxide transport
solution 10%
bicarbonate 60%
carbamino compounds 30%
Haldane effect
is removing oxygen from Hb increases the ability of Hb to pick up CO2 and CO2 generated H+, workes with the Bohr effect
Bohr effect
the oxygen dissociation curve is shifted right due to conditions in the tissues, meaning more oxygen is released
where is breathing controlled
medulla
dorsal firing
results in inspiration - active
gaps in dorsal firing
results in expiration - passive
increased dorsal firing
activates ventral firing causing forceful expiration - active
PC in pons
stimulation terminates inspiration
is stimulated when dorsal fire, regulates rhythm
apneustic centre
excites inspiratory medulla
