Chapter 10 part 4: temperature regulation

Question 1

what are some functions that our skin serves?

Answer 1

1. protects body surface
2. regulates body temperature
3. acts as an excretory organ
4. acts as a sense organ.

Question 2

what are the organs of the vertical section of the skin?

Answer 2

1. blood capillaries
2. hair follicle
3. arteriole
4. hair excretor muscle
5. adipose tissue
6. hair
7. sweat pore
8. nerve ending
9. sweat duct
10. sweat gland

Question 3

what are the structures of the skin that help to regulate body temperature?

Answer 3

1. blood vessels/arterioles
2. shunt vessels
3. sweat glands
4. sensory receptors

Question 4

how does blood vessels and arterioles regulate body temperature?

Answer 4

description:
- present under the skin surface.
- contraction of muscles in arteriole walls that causes the contraction and dilation of arterioles.
how:
- when skin arterioles dilate, more blood is sent to the blood capillaries in the skin which increases heat loss.
- when the skin arterioles constrict, less blood is sent to the blood capillaries in the skin which decreases/reduces heat loss.

Question 5

how does shunt vessels regulate body temperature?

Answer 5

description:
- connects skin arterioles to the skin venules.
- controls blood flowing through skin capillaries.
how: (antagonistic in movement)
- when the shunt vessels constrict, the skin arterioles dilate.
- when the shunt vessels dilate, the skin arterioles constrict.

Question 6

how does the sweat glands regulate body temperature?

Answer 6

description:
- coiled tube surrounded by numerous blood capillaries.
- secrete sweat made up mainly of water, dissolved salts and small amounts of urea.
- sweat flows through a sweat duct to a sweat pore at the skin surface.
how:
- sweats remove excess heat from the body by evaporation.
- the amount of sweat produced depends on the body’s external and internal environment.

Question 7

how does the sensory receptors regulate body temperature?

Answer 7

description:
- nerve endings that detect changes in the environment such as pain, pressure and temperature.
how:
- send nerve impulses to the hypothalamus in the brain when a stimulus is detected.

Question 8

how does the hypothalamus monitor and regulate body temperatures?

Answer 8

the hypothalamus receives information from:
- thermoreceptors in the skin which detect temperature changes in the environment.
- thermoreceptors in the hypothalamus which detect changes in the temperature of the blood.

Question 9

how is excess heat removed to prevent the body from overheating?

Answer 9

• the body gains heat and loses heat all the time and excess heat needs to be removed to prevent the body from overheating.
  
  • heat is released during cellular respiration, especially in the muscles and liver. this heat is distributed to the rest of the body through the bloodstream.
  • the body gains extra heat during (1) vigorous muscular activity, (2) consumption of hot foods and (3) being in warm environments.
    - the body loses heat through the skin, evaporation of water in sweat from the skin through exhaled air, faeces, and urine.

Question 10

what is the homeostasis control of body temperature when it rises above normal levels?

Answer 10

1. first stimulus: blood and skin temperatures rise above normal (e.g. on a hot day/due to vigorous muscular activity)
   RECEPTORS AND CONTROL CENTRE:
   - thermoreceptors in the hypothalamus and skin detect the temperature changes in the blood.
   - the hypothalamus of the brain is then stimulated and sends nerve impulses to relevant body parts.
   CORRECTIVE MECHANISM:
   - arterioles in the skin dilate and more blood capillaries in the skin, so more heat is lost.
   - sweat glands become more active and more sweat is produced, resulting in more heat being lost.
   - metabolic rate decreases and less heat is produced.
   RESULT:
   - blood and skin temperatures decrease to normal level.

Question 11

what is the homeostasis control of body temperature when it falls below normal levels?

Answer 11

2. second stimulus: blood and skin temperatures fall below normal (e.g. on a cold day)
   RECEPTORS AND CONTROL CENTRE:
   - thermoreceptors in the hypothalamus and skin detect the temperature changes in the blood.
   - the hypothalamus of the brain is then stimulated and sends nerve impulses to relevant body parts.
   CORRECTIVE MECHANISM:
   - arterioles in the skin constrict so less blood flows through the blood capillaries in the skin, so less heat is lost.
   - sweat glands become less active and more sweat is produced, resulting in less heat is lost.
   - metabolic rate increases and more heat is produced.
   - will shiver when it is very cold.
   RESULT:
   - blood and skin temperatures rises to normal level.