Thermoregulation

Question 1

What is the normal temperature for the body

Answer 1

the normal temperature is 36.7 oC (98.06oF)

the range is 36.3-37.1 oC

Question 2

What temperatures in the body are controlled

Answer 2

Core
Oral
Skin

Hands and feet are not controlled and are usually sacrificed

Question 3

How does the core temperature change with the circadian rhythm

Answer 3

temperature will flunctuate about 1 to 2 degrees over a 24 hour period with the coldest temperature being at about 6am in the morning

Question 4

What measures the temperature throughout the body

Answer 4

Thermoreceptors found in the skin, viscera, and the brain

viscera tells the temperature of the food

Question 5

How does temperature affect the body

Answer 5

temperature affects the enzyme activity and can change the cellular function

Question 6

What receptors tell us about the environment

Answer 6

Cutaneous thermoreceptors

these are often bimodal and distinguish temperature and touch

they can be warm or cold sensitive

there are 10x more cold sensitive thermorecptors than warm

Question 7

where does thermoreceptors send their information

Answer 7

to the hypothalamus specifically the Preoptic and the superoptic regions

Question 8

What sets the temperature for the body

Answer 8

the Hypothalamus

it has the connections to control the hormonal and autonomic and behavioral changes that are part of thermoregulation

Question 9

WHat are the three jobs of the hypothalamus when it comes to controlling the temperature

Answer 9

Determing the set point

Receiving info about current temperature

Deciding what to do based on these findings

Question 10

How does set point change with enviromental factors

Answer 10

with sleep: the temperature in the body decreases

with excersise: The temperature increases and there fore increases its set point

Question 11

what part of the hypothalamus responds to heat

Answer 11

Anterior hypothalamus

promotes heat loss behaviors

Question 12

What part of the hypothalamus responds to cooling

Answer 12

Posterior hypothalamus

Heat production behaviors

Question 13

What are ways the body produces heat

Answer 13

Autonomic nervous system (sympathetics)

Endorine: thyroxine and epinephrine

muscular activity

Non shivering thermogenesis

Question 14

How is muscle activity activated via being cold

Answer 14

shivering:
dorsomedial posterior hypothalamus will increase motor neuron excitation

INcrease in muscular voluntary activity:
Via the cortex to make an individual jump and run

Question 15

What are ways Non shivering thermogenesis occurs

Answer 15

Strong hormonal influence

• Thyroxin increases metabolic rate (cold is a stimulus for TRH release)
• Epinephrine

INcrease food intake to increase metabolism to produce heat

Drown adipose tissue for babies (innervated by the sympathetic nervous system)

Question 16

How does brown adipose tissue work

Answer 16

Low efficiency hydrolysis pf ATP via the uncoupling proteins that leads to heat production

has been found that white fat does express some of these uncoupling proteins to produce heat

Question 17

What are the two kinds of evaporative heat loss

Answer 17

insensible (respiratory)
Sweating (controlled)

Evaporative heat loss is energy that is lost as water evaporates

Question 18

what is convection

Answer 18

form of heat loss that is the movement of molecules away from contact (air heating and rising)

Question 19

what is conduction

Answer 19

form of heat loss that is the transfer of heat between objects in physical contact with one another

Question 20

What is radiation

Answer 20

form of heat losss where the infrared radiation transferring heat between 2 objects not in physical contact

you and the walls of the room

Question 21

significance of blood and heat loss

Answer 21

How much blood that is sent to the skin determines how much heat moves from the blood to the external environment

this is whay if someone is hot they become flushed so that the heat in the blood can escape through the skin

Question 22

How does sweating occur and what innervates it

Answer 22

Innervated by sympathetic cholinergic neurons that release acetylcholine that binds to a muscarinic receptor

Question 23

What is the two step process of sweating and the differences between a high and low flow rate

Answer 23

Step 1: Filtration of serum including the ions from the blood into the sweat gland

Step 2: as the fluid travels up to the skin surface, water and sodium are reabsorbed in the duct of the gland which creates a osmotic gradient to pull back water

Low flow rate:
-concentrated due to little wter being absorbed

high flow rate: lots of water and little sodium do to aldosterone keeping the Na+ in the body

Question 24

How is a fever produced and reduced

Answer 24

the hypothalamus increases the set point therefore the body will increase the bodies temperature this is done by:

Hypothalamus is informed by the Immune cells that release prostagladin E2 in the presence of endotoxins

therfore the hypothalamus increases the Temperature of the set point and the body will increase its temperature through shivering and moving blood flow away from the skin

once the bug is gone, no more prostagladin to tell the Hypothalamus to increase the bodies temperature so the hypothalamus sets the temp back to normal and the body will follow with heat loss