thermogenisesis Flashcards

1
Q

most of the heat in the body is generated how

A

by deep organs such as liver, brain, heart, GI and skeletal muscle

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2
Q

the rate of heat loss I dependent on what

A

body composition :more fat is a good insulator and prevent heat loss, people with low BMI will loose more heat

environmental temperature: colder environment = body loose heat, higher temperature = body gain heat

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3
Q

what is the maximum heat can the body absorb before it become fatal

A

50º

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4
Q

which one before heat or cold receptor that is ten time more present

A

cold

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5
Q

what does hot receptor produce if the temperature is too hot

A

activation potential

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6
Q

what does cold receptor produce if the temperature is too cold

A

action potential

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7
Q

T/F receptor are found superficialy on the skin and on deep body organ

A

t

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8
Q

what happen when the receptor produce an AP

A

it sends a message back to the hypothalamus. The hypothalamus controls temperature, it has temperature regulation centers connected to the hot and cold sensor neurons. The hypothalamus has a ‘set point’, this is the desired body temperature of 37°C.

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9
Q

what happen with the hypothalamus if the body becomes too cold or too hot

A

the hypothalamus will raise the set point, which tells the body to conserve heat and produce more heat.
the hypothalamus will raise the set point, which tells the body to loose heat and produce less heat.

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10
Q

to make temperature change the hypothalamus need to regulate what

A

peripheral vasoconstriction, peripheral vasodilation, shivering, brown adipose tissue, metabolic rate and sweating.

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11
Q

T/F thermoregulation has passive and active process to loose or gain heat

A

true

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12
Q

how does passive heat transfer occurs

A

by radiation, conduction, convection.

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13
Q

how does radiation occurs

A

Radiation is not nuclear! It is infrared radiation is emitted form the skin. Here is an infrared camera picture of the academic advisor.

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14
Q

how does conduction occurs

A

Conduction is when your body heats up surrounding air or water, or objects like seat you are sitting in.

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15
Q

how does convection occurs

A

Convection is when your body heats up air, and air is taken away by a breeze.

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16
Q

the body can actively loose heat by what

A

evaporation

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17
Q

what is evaporation

A

. Evaporation is panting, or sweating.

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18
Q

how can heat can be done passively

A

Adenosine triphosphate (ATP) is loaded with energy, up to 12,000 calories can be released. Thus, heat can be generated based on control of the chemical reaction rate of cells.

The digestion of food also releases heat

Exercise causes heat as a byproduct, normal muscle contractions when rapid can release energy from 150 times the amount of ATP than a resting muscle. Energy production is inefficient and so heat is released.

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19
Q

how does the body actively generate heat

A

Shivering thermogenesis ,Non-shivering thermogenesi

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20
Q

what is shivering thermogenesis

A

Cold environment or illness (e.g. flu) sympathetic nervous system causes muscles to tremor, the rapid contraction of muscle myosin proteins releases heat.The cold sensors will trigger this shivering response, and well as prevent sweating by sending signals to the hypothalamus.

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21
Q

what is non shivering thermogenesis

A

The sympathetic nervous system and the hormones including catecholamine hormones epinephrine, norepinephrine, and triiodothyronine, thyroxine, and others, increase metabolic rate of body resulting in more heat being generated. Brown adipose tissue is an endocrine tissue that specializes in non-shovering thermogenesis.

22
Q

which tissue regulate non-shivering thermogenesis

A

brown dispose tissue

23
Q

is the amount of heat made by BAT significant for overall body heat

A

no

24
Q

is BAT considerer an endocrine gland

A

no

25
Q

structure of BAT is derived from what

A

mesenchymal stem cell

26
Q

how does brown adipose tissue generate heat

A

using energy uncoupling, using uncoupling protein 1 (UCP1)
uncouples mitochondrial ATP energy production, generating heat instead. It does so by allowing protons to pass the membrane of the mitochondria without interacting with the normal ATP-generating proteins. This is considered to be a ‘leaky membrane’. Instead of chemical energy, heat is produced.

27
Q

someone lacking UCP-1 gene means what

A

means that they can’t make the uncoupling protein to they are only capable of creating heat using shivering thermogenesis

28
Q

BAT gets energy from

A

fat droplets within the brown adipose cells, it can also obtain fat and glucose from the extracellular fluid (blood plasma)

29
Q

explain the mechanism of heat production from BAT

A

Neural Control of BAT involves the sympathetic nervous interacts directly with BAT. Cold receptor nerves send signal to the brain ➔ Neural stimuli from autonomic nervous system ➔ increases energy consumption and uncoupling of mitochondria in BAT➔production of heat and secretion of other hormone-peptides.

30
Q

to power the proton gradient BAT uses what

A

uses free fatty acid and also glucose. It responds to nervous system directly, and responds to other hormones to regulate the amount of uncoupling and heat produced.

31
Q

who have more BAT between men and women

A

women

32
Q

Older individual have more or less BAT

A

less

33
Q

if you have high glucose in blood you have more or less BAT

A

more

34
Q

people who live in cold temperature zone have more or less BAT

A

moer

35
Q

acute cold exposure (16º for two hours) result in

A

ncreased the number
of BAT-positive people

36
Q

in health people BAT is located where

A

supraclavicular and around scapula

37
Q

which hormone is a neurotransmitter-hormone produced in brain neutron

A

orexin

38
Q

function of orexin

A

regulate arousal, wakefulness, appetite,also promotes the differentiation of BAT cells from mesenchymal stem cells

39
Q

which hormone of thermogenesis regulate arousal, wakefulness, appetite andalso promotes the differentiation of BAT cells from mesenchymal stem cells

A

orexin

40
Q

which hormone are required for non-shivering thermogenesis

A

orexin, diiodothyronine

41
Q

which hormone increase non-shivering thermogenesis

A

diiodothyronine

42
Q

which hormone increase the amount of insulin released by beta islet cells of the pancreases

A

incretin

43
Q

which hormone promote BAT thermogenesis

A

incretin

44
Q

which hormone stimulate receptor in hypothalamus

A

incretin

45
Q

which hormone increase the size, number, and efficiency of mitochondria throughout the body, resulting in higher basal metabolic rate and heat generation\

A

T3, T4

46
Q

which hormone induce mitochondria up regulation in BAT

A

T3, T4

47
Q

what happen in chronic cold temperature with TH

A

in chronic cold temperature thyroid stimulating hormone is elevated and can lead to a goiters in
people constantly exposed to cold

48
Q

what are the impact of norepinephrine on thermogenesis

A

NE interacts with the beta3 adrenergic receptor causing activation of hormone sensitive lipase
which in turn processes fat into free fatty acids, which is used by BAT to generate proton
gradient and heat

49
Q

which hormone increase overall body metabolism of glucose

A

norepinephrine

50
Q

which hormone directly communicate with BAT to increase uncoupling and heat generation

A

norepinephrine

51
Q

which test is done by immersing and individual hand in ice water

A

cold pressor test

52
Q

cold pressor test is what

A

is a cardiovascular test that is done by immersing an individuals hand in ice water and measuring the changes in blood pressure and heart rate. These responses occur as part of a non-shivering thermogenesis response.