Control of body temperature

Question 1

what are examples of ectotherms

Answer 1

Reptiles, fish etc

Question 2

What are examples of endotherms

Answer 2

Mammals, birds etc

Question 3

what type ( endo or ecto) can control their body temperature INTERNALLY.

Answer 3

• Endothermic organisms can control their body temperature internally by homeostasis.

Question 4

What is an example of a way an organism can combat extreme temperatures by changing their behaviour?

Answer 4

E.g for ectotherms- reptiles can gain heat by basking in the sun

• and Endotherms can lose heat by finding shade

Question 5

Out of endo/ecto whose internal temperature, depends more on the surroundings?

Answer 5

Ectotherms internal temperature depends more on their surroundings.

Question 6

which type of organism’s activity is not affected by external temperature?

Answer 6

• Endotherms are not affected by external temperatures, whereas ectotherms are,

Question 7

which type of organism has a high metabolic rate and generates a lot of heat from metabolic reactions

Answer 7

Endotherms

Question 8

What are the 3 mechanisms that REDUCE body temp:

when your hot

Answer 8

1) Sweating
2) Hairs lie flat
3) Vasodilation

Question 9

What are the 5 mechanisms that INCREASE body temp:

When your cold

Answer 9

1) Shivering
2) Less sweating
3) Hairs stand up
4) Vasoconstriction
5) Hormones (adrenaline and thyroxine)

Question 10

Sweating;

Answer 10

When the body is toooooo hot,

then more sweat is secreted from the sweat glands

how it actually works- The water in sweat evaporates from the surface of the skin and takes heat from the body.

Question 11

Hairs lie flat:

Answer 11

• We have a layer of hair that provides insulation by trapping air.
• When we are hot the erector pili muscles relax so our hairs lie flat.
• This means less air is trapped so screen is less insulated, so heat can be lost more easily

Question 12

Vasodilation:

Answer 12

This is when we are hot, and our arterioles near the surface of the skin dilate

• More blood flows through the capillaries
• which means more heat is lost from the skin by radiation so our temperature is lowered.

Question 13

Shivering:

Answer 13

When it is cold, muscles contract in spasms

- Which makes the body shiver and more heat is produced from an increase in respiration.

Question 14

Sweating less:

Answer 14

Less sweat is secreted from sweat glands when it is cold to reduce the amount of heat loss

Question 15

Hairs stand up:

Answer 15

When it is cold:

• Erector pili muscles contract
• which causes more air to be trapped
• So heat loss is reduced

Question 16

Hormones: ( to increase body temp)

Answer 16

2 hormones are released:

1) Adrenaline
2) Thyroxine

• These hormones increase metabolism so more heat is produced

Question 17

Vasoconstrictoin:

Answer 17

When it is cold:

• arterioles near the surface of the skin constrict
• so less blood flows through the capillaries in the surface layer of the dermis.
• so less heat is lost by radiation.

Question 18

When there is a “fall” in body temp ( thermoreceptors)

Answer 18

• Thermoreceptors detect that temperature is too low
• Hypothalamus sends signals to the effectors
• mechanisms to increase body temp occur ( EG vasoconstriction, shivering)
• More heat is produced and conserved by the body.

Question 19

When there is a “rise” in body temp ( thermoreceptors)

Answer 19

• Thermoreceptors detect that temp is too high
• Hypothalamus sends signals to the effectors
• mechanisms to decrease body temp occur ( EG sweating, vasodilation)
• more heat is lost and less heat is produced by the body.

Question 20

Thermoreceptors in the hypothalamus detect….

Answer 20

internal temp

Question 21

Thermoreceptors in the skin detect…

Answer 21

External temp

- thermoreceptors in the skin are called “ peripheral temperature receptors”