Thermoregulation

Question 1

What is the normal body temperature in celsius and farenheit?

Answer 1

37 degrees celsius

98.6 degrees farenheit

Question 2

What is the normal range of body temperature in celsius?

Answer 2

36.3 - 37.1

Question 3

What happens to core temperature over a range of environmental temperatures?

Answer 3

It is MAINTAINED, thus we know it is controlled!

Question 4

What is the fluctuation range of core temperature over a 24 hour period?

Answer 4

1-2 degrees

Question 5

When is core temperature the lowest?

Answer 5

6 am

Question 6

When is core temperature the highest?

Answer 6

Evening

Question 7

What is the reasoning behind core temperature fluctuations?

Answer 7

Circadian rhythm

Question 8

What measure temperature of our body and of the environment around us?

Answer 8

Thermoreceptors

Question 9

What are the locations for thermoreceptors?

Answer 9

Brain, viscera and cutaneous skin

Question 10

Where are the thermoreceptors that convey information about our core temperature?

Answer 10

Brain and/or viscera

Question 11

Where are thermoreceptors that convey information about the environmental temperature?

Answer 11

Cutaneous skin and or/viscera

Question 12

What do visceral thermoreceptors tell us?

Answer 12

Information about both our core temperature and the environmental temperature

Question 13

Cutaneous thermoreceptors tell us about the environmental temperature. Do we have more warm or cold sensitive thermoreceptors there?

Answer 13

10X more cold sensitive compared to warm sensitive

Question 14

Most common place to find visceral thermoreceptors?

Answer 14

Gut

Question 15

Visceral thermoreceptors sense the core temperature and?

Answer 15

Temperature of ingested food because it may change body temperature

Question 16

Brain thermoreceptors are located where?

Answer 16

Preoptic and superoptic regions of the hypothalamus

Question 17

Do we have more warm or cold sensitive thermoreceptors in the brain?

Answer 17

3X more warm sensitive compared to cold sensitive

Question 18

Where do the brain, visceral and cutaneous thermoreceptors relay their information about temperature?

Answer 18

Other parts of the hypothalamus for further processing

Question 19

What controls the set point for core temperature?

Answer 19

Neurons in the Hypothalamus

Question 20

With sleep, what happens to the core temperature set point?

Answer 20

It decreases

Question 21

With exercise, what happens to the core temperature set point?

Answer 21

It increases

Question 22

What region of the hypothalamus is responsible for heat loss?

Answer 22

Anterior hypothalamus

- In response to high temps. to avoid an increase in core temp.

Question 23

What region of the hypothalamus is responsible for heat production?

Answer 23

Posterior hypothalamus

- In response to low temps. to avoid a decrease in core temp.

Question 24

What type of tissue prevents heat loss?

Answer 24

Adipose tissue

Question 25

The high surface area in proportion to their size means that babies ___ heat better than adults

Answer 25

Lose

Question 26

What division of the ANS helps with heat production?

Answer 26

Sympathetic

Question 27

What endocrine molecules help with heat production?

Answer 27

Thyroxin and Epinephrine

Question 28

What controls voluntary muscular activity to produce heat?

Answer 28

Cortex (i.e jumping around)

Question 29

What controls involuntary muscular activity (shivering) to produce heat?

Answer 29

Dorsomedial posterior hypothalamus

Question 30

What does the dorsomedial posterior hypothalamus do?

Answer 30

Controls shivering - Sends excitatory signals down the spinal cord to help activate alpha motoneurons along with voluntary motion to produce heat -- why we shiver when we breath or do an activity

Question 31

Non-shivering thermogenesis

Answer 31

Increase in metabolism not due to muscles to produce heat

Question 32

What helps to activate non-shivering thermogenesis?

Answer 32

Thyroxin and epinephrine

Question 33

Where does non-shivering thermogenesis reside?

Answer 33

Brown adipose tissue

Question 34

Via _____, ATP hydrolysis leads to energy production

Answer 34

Uncoupling proteins

Question 35

Who is non-shivering thermogenesis critical in?

Answer 35

Infants

Question 36

Brown adipose tissue is innervated by?

Answer 36

Sympathetics

Question 37

Types of heat loss?

Answer 37

Evaporative, convection, conduction, radiation

Question 38

Heat evaporates as water (sweating or panting)

Answer 38

Evaporative heat loss

Question 39

Movement of molecules away from contact

Answer 39

Convection

Question 40

Transfer of heat between objects in physical contact with one another

Answer 40

Conduction

Question 41

Infrared radiation transferring heat between 2 objects NOT in physical contact

Answer 41

Radiation

Question 42

Change behavior to PREVENT a change in core temperature

Answer 42

Feed forward

Question 43

Change in core temperature has already occurred before a behavior could be changed

Answer 43

Feed back

Question 44

What determines how much heat is lost?

Answer 44

How much blood is sent to the skin

Question 45

How much blood is sent to the skin surface in a cold person?

Answer 45

Not much! (decrease heat loss)

Question 46

How much blood is sent to the skin surface in a warm person?

Answer 46

A lot! (increase heat loss)

Question 47

What is the innervation of sweating?

Answer 47

Sympathetic cholinergic

Question 48

The innervation of sweating releases what NT to what receptor?

Answer 48

Acetylcholine to muscarinic receptors

Question 49

Describe a sweat gland anatomically

Answer 49

Coiled region nearby many blood vessels and a duct that leads to skin surface

Question 50

First step of producing sweat from the blood?

Answer 50

Filter serum to include Na+ and Cl-

Question 51

Describe the filtrate content of sweat with low flow rates?

Answer 51

A lot of water resorbed in the duct and a lot of sodium released as sweat (very concentrated)

Question 52

Describe the filtrate content of sweat with high flow rates?

Answer 52

Little water resorbed in the duct and a lot of sodium resorbed so sweat is very dilute

Question 53

What causes little sodium to be released in the sweat with high flow rates?

Answer 53

Aldosterone reaction

Question 54

Controlled increase in body temperature as set point is increased

Answer 54

Fever

Question 55

Compare the body temperature to the set point in fever conditions

Answer 55

T set point >> T body

Question 56

Compare the body temperature to the set point in hyperthermia

Answer 56

T body >> T set point

Question 57

When T set point is >> T body, what happens?

Answer 57

Decrease heat loss and produce heat

Question 58

When T set point is << T body, what happens?

Answer 58

Increase heat loss and decrease heat production

Question 59

Explain why fever patients feel cold

Answer 59

As the set point temp increases, the body temp is lower than that and actively trying to heat up. This causes the patient to be producing heat and feel cold as their body temperature is behind the set point

Question 60

How do patients with hyperthermia feel?

Answer 60

They feel hot because their body temperature is higher than the set point temperature, so they are sweating and actively trying to lose heat

Question 61

Site where the hypothalamus regulates the ANS

Answer 61

Paraventricular nuclei

Question 62

Major efferent pathway for hypothalamus to regulate ANS

Answer 62

Dorsal Longitudinal Fasciculus (DLF)

Question 63

Main targets of the efferent pathway for hypothalamus to regulate ANS

Answer 63

Dorsal motor nucleus of vagus Nucleus ambiguus Parasymp. and sympathetic neurons in spinal cord