1. TOPIC OF PRESENTATION .
THERMOREGULATION IN
MAMMALS

2. WHAT IS THERMOREGULTION?
IT IS THE ABILITY OF AN ORGANISM
TO KEEP ITS BODY TEMPERATURE WITHIN CERTAIN BOUNDARIES ,EVEN WHEN TEMPERATURE SURROUNDING IS VERY DIFFERENT..

3. WHAT IS HEAT STROKE? If the body is unable to maintain
a normal temperature and it
increases significantly above normal ,a
condition called heat stroke.

4. What is hypothermia? The opposite condition, when body temperature
decreases below normal levels, is
known as hypothermia.

5. Mammals are endothermic.
They are warm blooded.
They are homeotherms

6. IN HOT CONDITIONS.
1.By sweating.
Sweat glands under the skin secrete sweat on to the surface of the skin .This causes heat loss by a evaporation.

7. By relaxing these muscles hairs on the skin become flat which
BY RELAXING THE ERRECTOR
PILI MUSCLES
By relaxing these muscles hairs
on the skin become flat which
increase the flow of hair by
trapping it next to the skin,
increasing heat loss
by convection.

8. ARTERIOLES VASODILATION
In arterial walls the smooth muscles
relax allowing increase blood flow
which comes to the
superficial Capillaries in the skin
increasing heat loss byradiation
and conduction.

9. PANTING Many animals pant rather than
sweat .This is the because of the large area of lungs and highly vascularised.

10. IN COLD CONDITIONS…..
Sweat stops being produced.
By contraction of errector pili muscles.
By contraction of these muscles attach hair on the skin become erect ad standing on end which acts as an insulating layer, trapping heat

11. Arteries present on the superficial surface of the
BY VASOCONSTRICTION
Arteries present on the superficial surface of the
skin constrict as a result blood is rerouted
away from the skin and towards the warme
r core of the body.

12. BY SHIVERING THERMOGENESIS
Muscles can also receive messages
from the thermoregulatory centre of
the brain (the hypothalamus)
to cause shivering.

13. THERMOREULATION IN OTHER MAMMALS.
Insulation by pelage or fat deposits.
By lowering the temperature of surface tissue .
Heat loss by poorly insulated patches of skin .
By countercurrent mechanism.

14. Winter sleep.
Hibernation .
Hibernation is a period of winter inactivity in which the hypothalamus of the brain slows the metabolic ,heart, and respiratory rates.
Following changes takes place during hibernation,

15. These mammals accumulate large quantitites of body fat before hibernations.
They retreat to a burrow or a nest during hibernation.
Their hypothalamus sets the thermostat of body at about 2C .
The respiratory rate of a hibernating ground squirel falls from 100 to 200 breaths per minute to about four breaths per minute.

16. The heart rate falls from 200 to 300 beats per minute to about 20 beats per minute.
A mammal may lose one third of its body weight during hibernation.