Homeostasis - Thermoregulation

Question 1

What is thermoregulation?

Answer 1

The regulation of body temperature. The balance of heat gain and heat loss in order to maintain a constant internal body temperature.

Question 2

What are the 4 methods of heat loss?

Answer 2

1. Evaporation
2. Convection
3. Radiation
4. Conduction

Question 3

What evaporation is?

Answer 3

Is the loss of heat by the evaporation of water into a gas.

Question 4

What is convection?

Answer 4

Moving air removes radiated heat.

Question 5

What is radiation?

Answer 5

Emission of electromagnetic radiation.

Question 6

What is conduction?

Answer 6

Transfer of heat by direct contact.

Question 7

What are the two forms of responses that come under thermoregulation

Answer 7

1. Behavioural responses
2. Physiological responses

Question 8

What are behavioural responses?

Answer 8

Involves peripheral thermoreceptors in the skin to detect hot or cold temperatures in the external environment. Behavioural responses are voluntary actions.

Question 9

What are physiological responses?

Answer 9

Involves central thermoreceptors in the hypothalamus to react to the internal environment. Physiological responses are involuntary responses.

Question 10

What are thermoreceptors?

Answer 10

A thermoreceptor will monitor the body’s core temperature in the hypothalamus, which detects the temperature of blood flowing through the brain.

Question 11

What are the types of thermoreceptors based on their location in the body?

Answer 11

1. Peripheral thermoreceptors
2. Central thermocreceptors

Question 12

What are peripheral thermoreceptors?

Answer 12

Peripheral thermoreceptors are temperature receptors in the skin or mucus that detect temperature changes in the external environment and send this information to the hypothalamus.

Question 13

What are central thermoreceptors?

Answer 13

Central thermoreceptors are receptors found in the hypothalamus that detect temperature changes in the internal environment.

Question 14

What are the two types of thermoreceptors

Answer 14

1. Cold receptors
2. Heat receptors

Question 15

What are cold receptors?

Answer 15

Cold receptors are stimulated by temperatures lower than normal. When cold receptors are stimulated the hypothalamus receives the information and initiates heat conservation and heat production mechanisms.

Question 16

What are heat receptors?

Answer 16

Heat receptors detect temperatures high than normal. When heat receptors are stimulated the hypothalamus receives this information and initiates a decrease in heat production and increase in heat loss mechanisms.

Question 17

What are 2 physiological changes controlled by the nervous system that prevents the temperature from falling?

Answer 17

1. Shivering
2. Vasoconstriction

Question 18

What are 2 physiological responses controlled by the endocrine system that prevent body temperature from falling?

Answer 18

1. Secretion of adrenaline and noradrenaline.
2. Increased production of thyroxine

Question 19

What are 2 physiological changes controlled by the nervous system to prevent the body temperature from rising?

Answer 19

1. Vasodilation.
2. Sweating.

Question 20

What is 1 physiological change controlled by the endocrine system to prevent the body temperature from rising?

Answer 20

1. Decrease metabolism - reduced secretion of thyroxine.

Question 21

What is shivering?

Answer 21

Is the continuous contraction and relaxation of the skeletal muscles. No work is done, so all energy goes towards heating the body.

Question 22

What is vasoconstriction?

Answer 22

Impulses from the hypothalamus via the sympathetic nerves cause smooth muscles in the arterioles in the skin to contract, reducing blood flow. Preventing heat loss due to radiation.

Question 23

What effect does the secretion of adrenaline and noradrenaline have?

Answer 23

The hypothalamus stimulates the adrenal medulla by sympathetic nerves secreting adrenaline and noradrenaline into the blood. These hormones increase cellular metabolism leading to increased heat production.

Question 24

What effect does the increased production of thyroxine have?

Answer 24

The hypothalamus causes the anterior lobe of the pituitary gland to secrete a thyroid-stimulating hormone, causing the thyroid gland to release thyroxine into the blood. Increased levels of thyroxine, increase metabolic rate resulting in an increase in body temperature.

Question 25

What is vasodilation?

Answer 25

Impulses from the hypothalamus via the sympathetic nerves cause the smooth muscle in the arterioles in the skin to relax, increasing blood flow and increasing heat loss due to radiation.

Question 26

What is sweating?

Answer 26

Sweating is the active secretion of fluid by the sweat glands onto the skin’s surface. The body will remove heat by using heat energy from the body to convert liquid (sweat) into gas (water vapour).

Question 27

What effect does a decreased metabolic rate have?

Answer 27

A decreased metabolic rate means less heat is produced in the body. This decrease is due to the reduced secretion of thyroxine.

Question 28

When does sweating occur?

Answer 28

When the external temperature is above 28 degrees.

Question 29

What happens when sweat is evaporated from the skin?

Answer 29

The body is cooled.

Question 30

Why sweating ineffective in environments with high humidity levels?

Answer 30

There is too much water in the air.

Question 31

What hormones increase metabolic rate?

Answer 31

1. Thyroxine
2. Adrenaline/noradenaline

Question 32

What are 4 methods to decrease heat loss?

Answer 32

1. Vasoconstriction
2. Reduction in sweating
3. Putting on a jumper and sheltering from the wind
4. Curling into a ball to reduce the surface area

Question 33

What are 3 methods to increase heat production?

Answer 33

1. Shivering
2. Increase voluntary activity
3. Increased metabolic rate

Question 34

What are 4 methods to increase heat loss?

Answer 34

1. vasodilation
2. Sweating
3. Removing clothing and turning on a fan
4. Spreading out to increase surface area

Question 35

What are 2 methods to decrease heat production?

Answer 35

1. Decrease voluntary activity
2. Decrease metabolic rate

Question 36

Heat is produced in the body via what process?

Answer 36

Cellular respiration.

Question 37

Describe how cellular respiration works.

Answer 37

Carbs, proteins and lipids are ingested. The chemical bonds that hold these molecules together are broken with ATP. When these bonds break they release energy used for muscular contractions and active transport but most energy is released as heat.

Question 38

What is the speed at which carbs, proteins and lipids are broken down known as?

Answer 38

Metabolic rate.

Question 39

What are the 3 main factors that influence an increase in metabolic rate?

Answer 39

1. Exercise
2. Stress
3. Body temperature

Question 40

What role does stress and the autonomic nervous system play in heat production?

Answer 40

Stress causes activation of the sympathetic system. This releases adrenaline and noradrenaline which increases metabolic rate. Therefore leads to an increased heat production.

Question 41

Write an SRMERF when the stimulus is an increase in temperature.

Answer 41

S - Increase in temperature.
R - Peripheral thermoreceptors in the skin.
M - Hypothalamus.
E - Sweat glans stimulate the production of sweat.
R - Sweat moves to the surface of the skin and is evaporated.
F - Decrease in temperature.