Question

Write short notes on major methods of heart gain in homeotherms exposed to cold temperature

Answer 1

Heat production in homeotherms
1] Exergonic oxidative reaction
• Food is oxidised to produce energy.
These reactions are carried through out
the life. Heat production is non-
shivering type heat energy or
thermogenesis.
• Ingestion of food – Casuses rise BMR &
also lead to increase in temperature.
This is known as specific dynamic
action of food. Spicy food causes more
rise in temperature.

• 2] Muscular contraction
• High muscular activity& exercises
increases body temperature (tb)from 37o
C upto 40 0C.
• Shivering thermogenesis – When
exposed to cold, rapid muscle contraction
is shown by the animals. It produces
16000 Kcal/m2/24hrs
• Ex. Man in 40C bath show 18 fold rise in
heat production by shivering.

3] Endocrine factors ( are fast in action )
• Non-epinephrine & epinephrine rise
metabolic rate, therefore temperature
increases.
• Thyroxins - (are slow in action)
• Hyperthyroidism – rises metabolic rate
rises temperature by 0.50C
• Hypothyroidism – decreases metabolic
rate decreases temperature by 0.50C

Answer 2

Answer:

If our body needs to warm up, the mechanisms of thermoregulation include: Vasoconstriction: As the blood vessels under the skin receive signals they become narrower to decrease the blood flow and retain heat to warm the inner body. Thermogenesis: This process is mainly seen in all warm-blooded animals.