36b. hypoxia 2

Question 1

what is the amount of oxygen in the blood related too?

Answer 1

the artiole levels of amount of saturation of haemolglobin.

more oxygen in blood = higher affinity = more haemoglobin picks it up

Question 2

what mmHg is the blood level at at sea level?

Answer 2

100 mmHg, saturation of PO2 = 100. haemoglobin is saturated

Question 3

why dont the periferial chemoreceptors do anything until about 60 mmHg

Answer 3

because from the oxygen haemoglobin dissocation curve it can be seen that nothing happnes to the saturation (ie how many oxygen molecules binding to haemglobin, 4:1) until about 60 mmHg.

After 60mmHg its a rapid decline of the pO2 and decerease the oxygen to tissues

Question 4

what is the acute response to a lower level of haemolgobin affinity?

Answer 4

a left shift in the dissociation curve causes hyperventaliation because of the periferial chemoreceptors (oxygen sensing ones) sensing low blood pH

which changes the respiratory muscles (effector) which makes breathing increase

Question 5

what is acclimitasatin?

Answer 5

exposure to low oxygen levels (left shift in curve) over an extended period of time

Question 6

what are three responses to acclimitisation to O2

Answer 6

1. hyperventillation
2. increase O2 carrying capacity of blood
3. capillary recruitment (growing more capillaries and skeletal muscle)

Question 7

what is the evolutinary adaptation for animals living at high or low altitudes?

Answer 7

the shape/function of haemoglobin

Question 8

what is p50?

Answer 8

a haemoglbins affinity for oxygen (on the x axis)

measured in mmHg and its pressure

the PO2 required to saturated 50% of the haemoglobin molecules

Question 9

how does the p50 related from non adapted mammals (ie humans) to adapted marine mammals?

Answer 9

the haemoglobin at 50% satuation (in mmHg) for non adapted mammas is lower than the mammals at lower altitudes.

its a right shift

Question 10

what is the problem in marine mammal diving?

Answer 10

the mammals isnt breathing, therefore tissue hypoxia

Question 11

what two adaptations to marine mammals have to be able to dive?

Answer 11

they can store more oxygen in the body

can use oxygen more efficently

Question 12

how do mammals increase lung storage

Answer 12

1. they have an increased storage of O2 in blood and muscle
   - increased blod volume
   - increase haemoglobin
   - increased myoglobin in muscle

not an increase in lung capacity because nitrogen expands and decompression sickness occurs

Question 13

how are three ways marine mammals efficently use O2?

Answer 13

1. diving reflex (HR drops - it uses a lot of oxygen)
2. change in circulation (different concentrations of where blood goes ie need it in the brain, not the other tissues)
3. decreased metabolic rate (because of decreased oxygen use)