thermogenisesis Flashcards
most of the heat in the body is generated how
by deep organs such as liver, brain, heart, GI and skeletal muscle
the rate of heat loss I dependent on what
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
what is the maximum heat can the body absorb before it become fatal
50º
which one before heat or cold receptor that is ten time more present
cold
what does hot receptor produce if the temperature is too hot
activation potential
what does cold receptor produce if the temperature is too cold
action potential
T/F receptor are found superficialy on the skin and on deep body organ
t
what happen when the receptor produce an AP
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.
what happen with the hypothalamus if the body becomes too cold or too hot
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.
to make temperature change the hypothalamus need to regulate what
peripheral vasoconstriction, peripheral vasodilation, shivering, brown adipose tissue, metabolic rate and sweating.
T/F thermoregulation has passive and active process to loose or gain heat
true
how does passive heat transfer occurs
by radiation, conduction, convection.
how does radiation occurs
Radiation is not nuclear! It is infrared radiation is emitted form the skin. Here is an infrared camera picture of the academic advisor.
how does conduction occurs
Conduction is when your body heats up surrounding air or water, or objects like seat you are sitting in.
how does convection occurs
Convection is when your body heats up air, and air is taken away by a breeze.
the body can actively loose heat by what
evaporation
what is evaporation
. Evaporation is panting, or sweating.
how can heat can be done passively
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.
how does the body actively generate heat
Shivering thermogenesis ,Non-shivering thermogenesi
what is shivering thermogenesis
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.
what is non shivering thermogenesis
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.
which tissue regulate non-shivering thermogenesis
brown dispose tissue
is the amount of heat made by BAT significant for overall body heat
no
is BAT considerer an endocrine gland
no
structure of BAT is derived from what
mesenchymal stem cell
how does brown adipose tissue generate heat
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.
someone lacking UCP-1 gene means what
means that they can’t make the uncoupling protein to they are only capable of creating heat using shivering thermogenesis
BAT gets energy from
fat droplets within the brown adipose cells, it can also obtain fat and glucose from the extracellular fluid (blood plasma)
explain the mechanism of heat production from BAT
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.
to power the proton gradient BAT uses what
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.
who have more BAT between men and women
women
Older individual have more or less BAT
less
if you have high glucose in blood you have more or less BAT
more
people who live in cold temperature zone have more or less BAT
moer
acute cold exposure (16º for two hours) result in
ncreased the number
of BAT-positive people
in health people BAT is located where
supraclavicular and around scapula
which hormone is a neurotransmitter-hormone produced in brain neutron
orexin
function of orexin
regulate arousal, wakefulness, appetite,also promotes the differentiation of BAT cells from mesenchymal stem cells
which hormone of thermogenesis regulate arousal, wakefulness, appetite andalso promotes the differentiation of BAT cells from mesenchymal stem cells
orexin
which hormone are required for non-shivering thermogenesis
orexin, diiodothyronine
which hormone increase non-shivering thermogenesis
diiodothyronine
which hormone increase the amount of insulin released by beta islet cells of the pancreases
incretin
which hormone promote BAT thermogenesis
incretin
which hormone stimulate receptor in hypothalamus
incretin
which hormone increase the size, number, and efficiency of mitochondria throughout the body, resulting in higher basal metabolic rate and heat generation\
T3, T4
which hormone induce mitochondria up regulation in BAT
T3, T4
what happen in chronic cold temperature with TH
in chronic cold temperature thyroid stimulating hormone is elevated and can lead to a goiters in
people constantly exposed to cold
what are the impact of norepinephrine on thermogenesis
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
which hormone increase overall body metabolism of glucose
norepinephrine
which hormone directly communicate with BAT to increase uncoupling and heat generation
norepinephrine
which test is done by immersing and individual hand in ice water
cold pressor test
cold pressor test is what
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.
