Thermoregulation Flashcards

1
Q

What is the normal body temperature in celsius and farenheit?

A

37 degrees celsius

98.6 degrees farenheit

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2
Q

What is the normal range of body temperature in celsius?

A

36.3 - 37.1

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3
Q

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

A

It is MAINTAINED, thus we know it is controlled!

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4
Q

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

A

1-2 degrees

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5
Q

When is core temperature the lowest?

A

6 am

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6
Q

When is core temperature the highest?

A

Evening

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7
Q

What is the reasoning behind core temperature fluctuations?

A

Circadian rhythm

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8
Q

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

A

Thermoreceptors

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9
Q

What are the locations for thermoreceptors?

A

Brain, viscera and cutaneous skin

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10
Q

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

A

Brain and/or viscera

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11
Q

Where are thermoreceptors that convey information about the environmental temperature?

A

Cutaneous skin and or/viscera

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12
Q

What do visceral thermoreceptors tell us?

A

Information about both our core temperature and the environmental temperature

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13
Q

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

A

10X more cold sensitive compared to warm sensitive

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14
Q

Most common place to find visceral thermoreceptors?

A

Gut

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15
Q

Visceral thermoreceptors sense the core temperature and?

A

Temperature of ingested food because it may change body temperature

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16
Q

Brain thermoreceptors are located where?

A

Preoptic and superoptic regions of the hypothalamus

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17
Q

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

A

3X more warm sensitive compared to cold sensitive

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18
Q

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

A

Other parts of the hypothalamus for further processing

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19
Q

What controls the set point for core temperature?

A

Neurons in the Hypothalamus

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20
Q

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

A

It decreases

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21
Q

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

A

It increases

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22
Q

What region of the hypothalamus is responsible for heat loss?

A

Anterior hypothalamus

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

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23
Q

What region of the hypothalamus is responsible for heat production?

A

Posterior hypothalamus

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

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24
Q

What type of tissue prevents heat loss?

A

Adipose tissue

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25
Q

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

A

Lose

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26
Q

What division of the ANS helps with heat production?

A

Sympathetic

27
Q

What endocrine molecules help with heat production?

A

Thyroxin and Epinephrine

28
Q

What controls voluntary muscular activity to produce heat?

A

Cortex (i.e jumping around)

29
Q

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

A

Dorsomedial posterior hypothalamus

30
Q

What does the dorsomedial posterior hypothalamus do?

A

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

31
Q

Non-shivering thermogenesis

A

Increase in metabolism not due to muscles to produce heat

32
Q

What helps to activate non-shivering thermogenesis?

A

Thyroxin and epinephrine

33
Q

Where does non-shivering thermogenesis reside?

A

Brown adipose tissue

34
Q

Via _____, ATP hydrolysis leads to energy production

A

Uncoupling proteins

35
Q

Who is non-shivering thermogenesis critical in?

A

Infants

36
Q

Brown adipose tissue is innervated by?

A

Sympathetics

37
Q

Types of heat loss?

A

Evaporative, convection, conduction, radiation

38
Q

Heat evaporates as water (sweating or panting)

A

Evaporative heat loss

39
Q

Movement of molecules away from contact

A

Convection

40
Q

Transfer of heat between objects in physical contact with one another

A

Conduction

41
Q

Infrared radiation transferring heat between 2 objects NOT in physical contact

A

Radiation

42
Q

Change behavior to PREVENT a change in core temperature

A

Feed forward

43
Q

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

A

Feed back

44
Q

What determines how much heat is lost?

A

How much blood is sent to the skin

45
Q

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

A

Not much! (decrease heat loss)

46
Q

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

A

A lot! (increase heat loss)

47
Q

What is the innervation of sweating?

A

Sympathetic cholinergic

48
Q

The innervation of sweating releases what NT to what receptor?

A

Acetylcholine to muscarinic receptors

49
Q

Describe a sweat gland anatomically

A

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

50
Q

First step of producing sweat from the blood?

A

Filter serum to include Na+ and Cl-

51
Q

Describe the filtrate content of sweat with low flow rates?

A

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

52
Q

Describe the filtrate content of sweat with high flow rates?

A

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

53
Q

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

A

Aldosterone reaction

54
Q

Controlled increase in body temperature as set point is increased

A

Fever

55
Q

Compare the body temperature to the set point in fever conditions

A

T set point&raquo_space; T body

56
Q

Compare the body temperature to the set point in hyperthermia

A

T body&raquo_space; T set point

57
Q

When T set point is&raquo_space; T body, what happens?

A

Decrease heat loss and produce heat

58
Q

When T set point is &laquo_space;T body, what happens?

A

Increase heat loss and decrease heat production

59
Q

Explain why fever patients feel cold

A

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

60
Q

How do patients with hyperthermia feel?

A

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

61
Q

Site where the hypothalamus regulates the ANS

A

Paraventricular nuclei

62
Q

Major efferent pathway for hypothalamus to regulate ANS

A

Dorsal Longitudinal Fasciculus (DLF)

63
Q

Main targets of the efferent pathway for hypothalamus to regulate ANS

A

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