ch15 - thermoregulation

What is thermoregulation

Process of maintaining a relatively constant core body temperature 

Why is thermoregulation important 

To maintain optimum enzyme activity and prevent enzymes from denaturing

What process is thermoregulation an example of 

Negative feedback

What is an endotherm and name examples 

An animal which regulates their body temperature through various internal processes and behavioural changes 

e.g. mammals, birds

What is an ectotherm and name examples 

An animal whose body temperature fluctuates depending on changes in external temperature, however can regulate using some behavioural changes 

e.g. reptiles, fish 

Name 4 physiological responses involved in regulating body temp in Endotherms

Hairs on the skin 

Sweat glands in the skin 

Blood vessels 

Skeletal muscles

Describe how hairs on the skin operate when: too hot, too cold 

Too hot- hairs flatten because erector pili muscles relax 

Too cold- hairs rise because erector pili muscle contract 

Describe how sweat glands in the skin operate when: too hot, too cold 

Too hot- more sweat produced, more evaporates creating cooling effect 

Too cold- less sweat produced, conserves body heat

Describe how blood vessels operate when: too hot, too cold  

Too hot- vasodilation, arterioles near skin dilate increasing blood flow 

Too cold- vasoconstriction, arteriole near skin constrict decreasing blood flow 

Describe how skeletal muscles operate when: too hot, too cold 

Too hot- fewer contractions 

Too cold- muscles contract rapidly, shivering, this process requires ATP so there is increased cellular respiration which releases heat during the process

What parts of the body are involved in thermoregulation

peripheral receptors

hypothalamus

how do peripheral receptors help regulate temperature

detects changes in external skin temperature via thermoreceptors

how does the hypothalamus help regulate temperature

detects changes in core body temperature and blood temperature via thermoreceptors  

What two centres does hypothalamus use to regulate temperature

Heat gain centre 

Heat loss centre 

What occurs when there is an increase in body temp

-Peripheral receptors in skin detect change

-impulses are sent to heat loss centre in hypothalamus

-impulses sent to effectors e.g. muscle and sweat glands to bring temperature back down 

What occurs when there is decrease in body temp 

-Peripheral receptors in skin detect change

-impulses are sent to heat gain centre in hypothalamus

-impulses are sent to effectors e.g. muscle and sweat glands to bring temperature back up

Name a behavioural response to regulate body temp used by Endotherms and Ectotherms 

Too hot- move into shade

Too cold- move into sunlight