Thermoregulation (Karius) Flashcards

1
Q

What parts of the body change temperature the most rapidly?

A

Feet, then hands, then skin

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2
Q

About how much does the core temperature change throughout the day?

A

1-2 degrees

Lowest at 6 am

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3
Q

What measures core temperature & the temperature around us?

A

Thermal Receptors

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4
Q

What are the cutaneous thermoreceptors most sensitive to?

A

Cold (10x as much as warm)

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5
Q

What information do the visceral thermoreceptors transmit?

A

Threats from ingested food that may change body temperature => hypothalamus

  • Example: ice cream (causes brain freeze which would decrease blood temp. of brain)
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6
Q

Where are the thermoreceptors of the brain located?

A

Pre-optic and superoptic region of hypothalamus

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7
Q

What are the thermoreceptors in the brain most sensitive to?

A

Heat (3x as much as cold)

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8
Q

What structure determines the set body temperature, receives info about current temperature and decides what to do?

A

Hypothalamus

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9
Q

What happens to the core temperature when you sleep and exercise?

A
  • Sleep: T decreases b/c set point decreases
  • Exercise: T increases b/c set point increases
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10
Q

What receptors determine the core temperature of the body

A

Visceral and hypothalamic (preoptic & superoptic) thermal receptors

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11
Q

What does the posterior region of hypothalamus respond to?

A

Responds to cold by activating heat producing behavior

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12
Q

What does the anterior region of the hypothalamus respond to?

A

Responds to heat by activating heat loss behaviors

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13
Q

Why do babies need more adipose tissue?

A

Babies have higher surface area in proportion to size and will lose heat faster than adults

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14
Q

What systems can be used to produce heat

A
  • Autonomic nervous system (esp. sympathetic)
  • Endocrine
    • Thyroxine
    • Epinephrine
  • Muscular activity
    • Voluntary
    • Involuntary (shivering)
  • Non-shivering thermogenesis
    • increase in metabolism
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15
Q

What part of the hypothalamus is responsible for shivering?

How does it do this?

A

Dorsomedial posterior hypothalamus => increase motor neuron excitation

You are cold and trying to produce heat

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16
Q

What division of the autonomic nervous system is involved in heat production?

A

Sympathetic Nervous System

17
Q

In non-shivering thermogenesis, what hormone is released in response to cold?

A

Thyroxin-Releasing hormone => Thyroxin

Epinephrine

18
Q

What activates hydrolysis of ATP in brown fat?

A

Sympathetic fibers & circulating Epinephrine

19
Q

How is Brown Adipose Tissue used to produce heat

A

Hydrolysis of ATP via uncoupling proteins leads to heat production

20
Q

What are the two kids of evaporative heat loss?

A

Insensible (respiratory)

Sweating (controlled)

21
Q

What is convection?

A

Movement of molecules away from contact

Air Heating and Rising

22
Q

What is conduction?

A

Transfer of heat between objects in physical contact with one another

heat from body dissipating to chair

23
Q

What is radiation?

A

Transfer of heat between 2 objects that are not in physical contact

24
Q

What is the innervation to the sweat glands?
Activated by what NT & what receptor does it bind?

A

Sympathetic cholinergic innervation

NT: Acetylcholine - binds mAChR

25
Q

If there is a low flow rate of sweat, what is the sodium concentration in sweat?

A

High (couldn’t follow water)

26
Q

If there is a high flow rate of sweating, what is the sodium concentration?

A

Low (no time to reabsorb water)

27
Q

What happens to the body when there is a fever?

A

Set Point increases and will be greater than body temperature

  • Endotoxins and Prostaglandin released
28
Q

Explain the following characteristics of a Fever

  1. Core Temp
  2. Set Point
  3. Active Thermoregulatory response
  4. Signs present
  5. Subjective perception
  6. Cause
A
  1. Increased
  2. Increases
  3. Heat production
  4. Pallor, shivering, behavioral changes associated with being cold
  5. Subjectively cold
  6. Infectious agents producing inflammatory mediators acting in brain
29
Q

Explain the following characteristics of Hyperthermia

  1. Core Temp
  2. Set Point
  3. Active Thermoregulatory response
  4. Signs present
  5. Subjective perception
  6. Cause
A
  1. Increased
  2. Normal
  3. Heat loss
  4. Flushes skin, sweating, behavioral changes associated with being hot
  5. Patient describes as being hot
  6. Increased heat production or decreased ability to eliminate heat (dehydration)
30
Q

How does the hypothalamus regulate the autonomic nervous system for thermoregulation

A
  • Dorsal longitudinal fasiculus (MAJOR)
  • Medial forebrain bundle
  • Mammillotegmental tract
31
Q

What is the major hypothalamic nucleus associated with autonomic control of temperature

A

Paraventricular nuclei via dorsal longitudinal fasciculus (DLF)

32
Q

Where does the dorsal longitudinal fasciculus send it’s axons

A

Dorsal motor nucleus of the vagus

Nucleus ambgiguous

Parasympathetic and sympathetic neurons in spinal cord