Mammalian Adaptation (Cram Set) Flashcards
How do you calculate PO2?
Barometric pressure x percentage composition
PAO2 and PaO2?
A ? alveolar
a ? arterial
partial pressures
Will PAO2 be higher or lower than PO2?
Lower when air inhaled because oxygen moves into blood via gas exchange diffusion down a conc gradient
Picks up water vapour pressure
Lung CO2 dilutes O2 concentration
Cardiovascular status of a cow at high altitudes?
High altitude pulmonary hypertension
How does increased pressure in right ventricle come about at high altitudes?
Increased respiration rate Increased heart rate Increased blood flow Vasoconstriction in lungs due to hypoxia Increased resistance in pulmonary capillaries, arterioles, artery ?> right ventricle pressure increases
How does the oedema come about?
Increased pressure in blood vessels leads to more fluid in extracellular tissues ? Starling’s principle
Why is brisket life?threatening?
Right sided congestive heart failure ? left sided ventricular failure
Pulmonary oedema ? lungs cannot expand, drown in own fluid
Pressure can blow out right ventricle valves
Treating an animal with brisket disease?
Decrease animal’s altitude
Centesis (pericardio, thoraco, abdomino)
Hypobaric chamber
Diruetics
What do peripheral chemoreceptors respond to changes in?
Oxygen and pH
Immediate effect to hypoxia?
Hyperventilation
After 1?2 days?
Increase of DPG in red blood cells ? shifts O2 dissociation curve to right so more goes to tissues
After 2?5 days?
Kidneys begin excreting HCO3
After 2 weeks?
Increase of haemoglobin in blood
Production of erythropoietin from bone ? more RBCs
How do you calculate mean arterial pressure?
1/3 x pulse pressure + diastolic pressure
What do central chemoreceptors respond to?
H+ ions in CSF
What is pulse pressure?
Difference between systolic and diastolic pressure readings
Difference in histology between cow and yak pulmonary arterioles?
Yak ? less muscle in tunica media, less amount of vasoconstriction, less pressure
What is p50?
The partial pressure of oxygen at which haemoglobin is 50% saturated
P50 adaptation in high altitude dwelling animals?
Lower p50 values = higher affinity for oxygen, more oxygen taken up in lungs, useful in hypoxic conditions
Disadvantage of low p50 value?
May not dissociate with oxygen well in tissues
How does hypobaric hypoxia cause alkalosis?
Hypoxia ?> hyperventilation ?> CO2 blow off ?> increase in pH
Cerebral blood vessels constrict in response to absence of CO2 in blood. Bird/mammal difference and advantage/disadvantage?
Birds ? do not vasoconstrict ? no fainting
How is the avian respiratory system designed better than the mammalian system?
One way air flow through lungs ? maintains concentration gradient
9 air sacs
Countercurrent gas exchange between parabronchary and respiratory arterioles
Stiff lungs
Respiratory adaptations of diving mammals?
Exhale before diving ? so lungs collapse, lungs are designed for this ? also no nitrogen bubbles ? reduces buoyancy
Higher concentration of haemoglobin and myoglobin and air stored in blood and muscle, not lungs
Lowered heart rate
More adapted to anaerobic respiration
Ribs squeeze air out of lungs at deep dives
Seals ? little sensitivity to CO2
No increase in ventilation rate ?> no alkalosis
Conscious breathing
