Thermoregulation

Question 1

How do core temperatures vary?

Answer 1

1-2 degrees over a 24 hour period and is at 36.7 degrees C in the morining

Question 2

What are the jobs of the viscera thermoreceptors?

Answer 2

1) Detects core temp

2) Detects threats to core temp

Question 3

What is a threat to our core temperature that can be detected by the viscera thermoreceptors?

Answer 3

Temp of food

Question 4

Thermoreceptors in what location are often bimodal (respond to temperature change and high pressure stimulus)?

Answer 4

Cutaneous

Question 5

Cutaneous thermoreceptors can either be warm or cold sensitive. There are 10x the amount of thermoreceptors that are sensitive to what?

Answer 5

Cold sensitive

Question 6

What do cutaneous thermoreceptors tell us?

Answer 6

About environmental conditions

Question 7

What structure does the visceral thermoreceptors signal to about threats to the core temperature?

Answer 7

Hypothalamus

Question 8

Where is the major site for thermoregulation?

Answer 8

Hypothalamus

Question 9

Where in the hypothalamus are the thermoreceptors located?

Answer 9

Pre-optic and supraoptic regions

Question 10

In the hypothalamus, there are 3x the amount of thermoreceptors that are sensitive to what?

Answer 10

Warm sensitive

Question 11

What receptors work together to detect core temperature?

Answer 11

Visceral and brain thermoreceptors

Question 12

What does the hypothalmus determine?

Answer 12

The set point of the core temp

Question 13

When you are sleeping what happens to your core temperature?

Answer 13

It decreases (decrease in set point)

Question 14

When you are exercising what happens to your core temperature?

Answer 14

It increases (Increase in set point)

Question 15

If you start to cool down what part of the hypothalamus starts to become more active in order to increase heat production behavior?

Answer 15

The posterior aspect

Question 16

If you start to get too hot what part of the hypothalamus starts to become more active in order to increase heat loss behavior?

Answer 16

The anterior aspect

Question 17

In babies, the high surface area in proportion to their size means they lose heat better than adults. What do babies have to combat this?

Answer 17

Lots of Subq fat

Question 18

What are some hormones that are released to increase heat production?

Answer 18

Thyroxine and Epi

Question 19

What part of the hypothalamus causes shivering?

Answer 19

Dorsomedial posterior hypothalamus

Question 20

The dorsomedial posterior hypothalamus sends axons down the spinal cord to the?

Answer 20

The motoneurons and increases their excitability

Question 21

What does thyroxine do?

Answer 21

Increases metabolic rate

Question 22

What are some ways to induce non-shivering thermogenesis?

Answer 22

1) Thyroxine and Epi release
2) Increase food intake to increase metabolism
3) Brown adipose tissue

Question 23

Low efficiency hydrolysis of ATP via uncoupling proteins leading to more heat production than otherwise is seen in what?

Answer 23

Brown adipose tissue

Question 24

What is brown fat innervated by?

Answer 24

Sympathetic fibers and also activated by circulating epinephrine

Question 25

What population is brown fat critical in?

Answer 25

Infants

Question 26

What is the term for heat lost as water evaporates?

Answer 26

Evaporative heat loss

Question 27

What are the two types of evaporative heat loss?

Answer 27

1) Insensible (breathing)

2) Sweating (controlled)

Question 28

What is the term for movement of molecules away from contact (air heating and rising)?

Answer 28

Convection heat loss

Question 29

What is the term for transfer of heat between objects in physical contact with one another?

Answer 29

Conduction heat loss

Question 30

What is the term for transferring heat between two objects not in physical contact?

Answer 30

Radiation heat loss

Question 31

How much blood is sent to the skin determines how much heat moves from?

Answer 31

Blood to external environment

Question 32

What is the innervation of the sweat glands?

Answer 32

Sympathetic muscarinic receptors

Question 33

What is the initial process of sweating?

Answer 33

Filtration of serum, including the Na, Cl

Question 34

During sweating, as the fluid travels up to the skin surface what are reabsorbed (taken back to the blood) in the duct of the sweat gland?

Answer 34

Water and sodium

Question 35

What is the flow rate of sweating when the sweat has little water (lots reabsorbed) and high sodium?

Answer 35

Low flow rate (not that hot)

Question 36

What is the flow rate of sweating when the sweat has lots of water (no time) and low sodium?

Answer 36

High flow rate (very hot)

Question 37

What causes sodium to not be lost in sweat during high flow rates?

Answer 37

Aldosterone

Question 38

What happens to the set point during the start of a fever?

Answer 38

The set point becomes greater than body temp

Question 39

What happens to heat production and heat loss during a fever when the immune cells are active?

Answer 39

Increase heat production and decrease heat loss because the set point is higher than body temp

Question 40

What happens to the set point during a fever after there is no more activation of immune system?

Answer 40

The set point is less than the body temp

Question 41

What happens to heat production and heat loss during a fever when the immune cells are inactive?

Answer 41

Decrease in heat production and increase in heat loss because the set point is lower than body temp