Mammalian Adaptation (Cram Set)

Question 1

How do you calculate PO2?

Answer 1

Barometric pressure x percentage composition

Question 2

PAO2 and PaO2?

Answer 2

A ? alveolar
a ? arterial
partial pressures

Question 3

Will PAO2 be higher or lower than PO2?

Answer 3

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

Question 4

Cardiovascular status of a cow at high altitudes?

Answer 4

High altitude pulmonary hypertension

Question 5

How does increased pressure in right ventricle come about at high altitudes?

Answer 5

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

Question 6

How does the oedema come about?

Answer 6

Increased pressure in blood vessels leads to more fluid in extracellular tissues ? Starling’s principle

Question 7

Why is brisket life?threatening?

Answer 7

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

Question 8

Treating an animal with brisket disease?

Answer 8

Decrease animal’s altitude
Centesis (pericardio, thoraco, abdomino)
Hypobaric chamber
Diruetics

Question 9

What do peripheral chemoreceptors respond to changes in?

Answer 9

Oxygen and pH

Question 10

Immediate effect to hypoxia?

Answer 10

Hyperventilation

Question 11

After 1?2 days?

Answer 11

Increase of DPG in red blood cells ? shifts O2 dissociation curve to right so more goes to tissues

Question 12

After 2?5 days?

Answer 12

Kidneys begin excreting HCO3

Question 13

After 2 weeks?

Answer 13

Increase of haemoglobin in blood

Production of erythropoietin from bone ? more RBCs

Question 14

How do you calculate mean arterial pressure?

Answer 14

1/3 x pulse pressure + diastolic pressure

Question 15

What do central chemoreceptors respond to?

Answer 15

H+ ions in CSF

Question 16

What is pulse pressure?

Answer 16

Difference between systolic and diastolic pressure readings

Question 17

Difference in histology between cow and yak pulmonary arterioles?

Answer 17

Yak ? less muscle in tunica media, less amount of vasoconstriction, less pressure

Question 18

What is p50?

Answer 18

The partial pressure of oxygen at which haemoglobin is 50% saturated

Question 19

P50 adaptation in high altitude dwelling animals?

Answer 19

Lower p50 values = higher affinity for oxygen, more oxygen taken up in lungs, useful in hypoxic conditions

Question 20

Disadvantage of low p50 value?

Answer 20

May not dissociate with oxygen well in tissues

Question 21

How does hypobaric hypoxia cause alkalosis?

Answer 21

Hypoxia ?> hyperventilation ?> CO2 blow off ?> increase in pH

Question 22

Cerebral blood vessels constrict in response to absence of CO2 in blood. Bird/mammal difference and advantage/disadvantage?

Answer 22

Birds ? do not vasoconstrict ? no fainting

Question 23

How is the avian respiratory system designed better than the mammalian system?

Answer 23

One way air flow through lungs ? maintains concentration gradient

9 air sacs

Countercurrent gas exchange between parabronchary and respiratory arterioles

Stiff lungs

Question 24

Respiratory adaptations of diving mammals?

Answer 24

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

Question 25

What is the most significant variable when talking about resistance?

Answer 25

Radius of vessel