mnsr 23

Question 1

To maintain body temp when the T is too low

Answer 1

• counter current exchange
• piloerection - vestigial response
• vasoconstriction
• shivering

Question 2

The concept of counter current exchange

Answer 2

heat lost by outgoing arterial blood reheats returning veinous blood and minimises heat loss in limbs

Question 3

the design of heat exchange vascular network varies from

Answer 3

simple side by side to complex rate structures

Question 4

the counter current exchange minimises

Answer 4

conductive and radiative heat loss in animals in cold conditions

Question 5

an example of counter current exchange mechanism is

Answer 5

keeping the testes at optimum temp to produce healthy sperm which is 3-4 lower than body temp. As temp increases, the cremaster and darts muscles relaxes, lowers the scrotum further away from the body which increases effective length pf venous paminiform plexus

Question 6

increased cooling in the testis is facilitated by

Answer 6

larger scortal surface area where body heat is lost. the body minimises the heat loss from blood by counter current exchange by passing it through pampinifrom plexus

Question 7

the concept of vasocostriction is when

Answer 7

-the veinous flow near skin reduces the temp
- its accomplished by shunts and sphincters
- blood flows through sub cutaneous capillaries network control by sphincters muscles and shunts

Question 8

frostbites are caused by

Answer 8

blood is redirected away from extremities supplying only vital organs

Question 9

shivering is when

Answer 9

-low frequency (2-3 hz) involuntary muscle spams
-shivering is strenuous vigours cycling
-55% of metabolic activity is lost as heat. heat energy released during metabolic activity is used to warm ur body

Question 10

mechanisms when the its too warm

Answer 10

• vasodilation: causes subcutaneous capillaries to be filled w blood ( fever)
• sweating ( perspiration ) steals latent heat of vaporisation from the skin to form vapour and loss of heat cools the body

Question 11

perspiration is the only cooling mechanism which

Answer 11

works when outside t > 37 degree c
( before paracetamol, ppl use isopropyl alcohol bc it has lower boiling point than water and evaporates more vigorously at 37 and accelerates cooling )