resp physiology quick Flashcards
“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”
Fick’s law of diffusion
“increased release of O2 from Hb at tissues - sigmoid curve moves to the right”
Bohr effect
“total pressure exerted by a gas mixture is the sum of the partial pressures of each individual component in the gas mixture”
Dalton’s Law
“at constant temperature as volume of gas increases the pressure exerted decreases”
Boyle’s Law
“the amount of gas that will dissolve in a given value is proportional to the partial pressure of the gas at equilibrium within the liquid”
Henry’s Law
What is the law of La Place
P= 2T/r
the inward directed collapsing pressure is proportional to 2 times the surface tension and inversely proportional to the radius of the alveoli
Removing O2 from Hb increases Hb’s affinity for CO2 and CO2 generated H+
Haldane effect
what do the external intercostal muscles do in inspiration
lift ribs
push out sternum
increase AP dimension of thoracic cavity
what are the accessory respiratory muscles used in forceful inspiration
scalenus
sternocleidomastoid
what are the muscles of active expiration
internal intercostal muscles
abdominal muscles
volume of air entering/leaving the lungs in a single breath
500ml
tidal volume
volume of air that can be maximally inspired beyond the tidal volume
3000ml
inspiratory reserve volume
what is the inspiratory capacity
3500ml
TV + IRV
volume of air that can be maximally expired beyond the tidal volume
1000ml
expiratory reserve volume
volume of air remaining in the lungs after maximal expiration
1200ml
residual volume
volume of air remaining in the lungs after a normal expiration
2200ml
functional residual capacity
volume of air that can be maximally expired following maximal inspiration
4500ml
vital capacity
what is the equation for total lung capacity
VC + RV
what is the equation for vital capacity
TV + ERV + IRV
volume of air that can be forcefully maximally expired following maximum inspiration
forced vital capacity
what is FEV1
the volume of air that can be expired during the 1st second in an FVC
what is peak flow
what does a decrease show
maximum speed at which a patient can move air out of lungs
obstructive disease
what does decreased pulmonary compliance show
restrictive lung disease
volume of air exchanged between the atmosphere and alveoli per minute
alveolar ventilation
volume of air breathed in and out per minute
pulmonary ventilation
part of airways not available for gas exchange
anatomical dead space
ventilated alveoli that aren’t adequately perfused
alveolar dead space
physiological dead space
anatomical dead space + alveolar dead space
what is the main influence for the rate of transfer of O2
partial pressure
what is the main influence for the rate of transfer of CO2
diffusion coefficient
what type of alveolar cell does gas exchange occur accross
type I alveolar cells
what is the enzyme in RBCs that catalyses the formation of bicarbonate for transport of CO2 in blood
carbonic anhydrase
what is the name of the complex that generated normal breathing rhythm and where is it
pre-botzinger complex in medulla
where can the breathing rhythm be modified
pons
what causes inspiration
firing of dorsal neurones in medulla
what causes passive expiration (ceased inspiration)
ceased firing of dorsal neurones
what causes active expiration
firing of ventral neurones - cause excitation of secondary respiratory muscles
when ventral neurones fire what happens to the pneumotaxic centre in the pons
inhibits inspiration
what kind of breathing occurs without the pneumotaxic centre
apneusis
what does the apneustic centre in the pons do to inspiration
prolongs it
stretch receptors detect when the lung is sufficiently inflated and send afferent trigger to inhibit inspiration
hering-brueur reflex
is the HB reflex active during normal respiration
no
increased moving to limbs leads to increased breathing
joint receptor reflex
what do central chemoreceptors detect and where are they found
[H+] of CSF
near medulla
what receptors are responsible for CO2 drive of respiration
central
what do the peripheral chemoreceptors detect and where are they found
tension of O2 CO2 and [H+]
carotid and aortic bodies
what receptors are responsible for H+ drive of respiration
peripheral
what receptors adjust for metabolic acidosis
peripheral
what receptors mediate the hypoxic drive of respiration and when are they stimulated
peripheral
PaO2 < 8
give 4 things that occur in adaptations to high altitude
increased no. of capillaries and mitochondria
polycythaemia
increased 2,3-biphosphoglycerate
kidneys conserve acid
what does 2,3-biphosphoglycerate do
liberates O2 from haemoglobin
