Physiology 3

Question 1

What are the two ways which O2 is transported in the blood

Answer 1

Dissolved into the blood
- only a small percentage due to high temp of blood
Bound to hemoglobin = majority of O2
- each binds up to 4 O2
- makes up 1/3 RBC
has cooperative binding

Question 2

What are the three ways which CO2 is carried around the blood stream

Answer 2

Dissolved into the blood
- only a small percentage due to high temp of blood
some bound to hemogobin HbCO2
Majority convered to bicarbonate
- CO2 + H2O -> carbonic acid (H2CO3) -> H+ and HCO3-
HCO3- undergoes chloride shift -> HCO3- leaveRBC Cl- enters
H+ in tissue lowers pH

Question 3

What is a hemoglobin binding curve

Answer 3

Hemoglobin binding cuves display O2 saturation vs pO2
Cooperative behavier creates sigmoidal shape -> difficulties to bind first O2 then becomes progressivly easier to bind subsequent
This shape enables Hb to hold onto O2 unless tissue pO2 is very low

Question 4

What are the two roles of Hb and how does curve shifting effect Hb ability to do these roles

Answer 4

External respiration -> gain O2 at alveolar membrane
Internal respiration -> loss O2 at tissue

Curve shift = shift right -> reduced O2 binding effinity -> easier release
- increased temp leads to curve shift
- decrease in pH leads to curve shift

Both occur in tissue due to excersise which promotes O2 release when more is required

Question 5

How is control of respiritory function controled

Answer 5

Via ventilation to keep O2 and CO2 within normal range
challage as they are highly variable dependant on activity

Uses receptors send afferent information -> control center in brain stem sends afferent information -> effector

Question 6

What is the function of chemoreceptors in respiritory control

Answer 6

CO2 and O2 chemoreceptors detect blood levels -> send afferent information
Increased respirotry rate if O2 is to low or CO2 is to low

primary detector is CO2 as it is a more controled variable

Question 7

What is the function of barrowreceptors in respiritory control

Answer 7

Barrow receptors detect MAP (aortic arch + carrotid sinuses)
If MAP decreases -> respitory rate increases
If MAP increases -> respiritory rate decreases

Question 8

What is the function of protective reflexes in respiritory control

Answer 8

protective reflexes detect the streach of the lungs
afferent information is sent and efferent returns to prevent overstreaching and damage to the lungs

Also detect irritations which can lead to sneeze or coughing