Temperature Regulation (Pages 29-34)

nutrient pools

built up storage of nutrients (amino acids/carbs/fats)

nutrient pools

form when a molecule is taken into the body, but is not needed for energy, growth, or maintenance

CO2 and urine

two waste produces

gluconeogenesis

process of creating glucose or glucose derivatives from noncarbohydrate sources

proteins

can be deaminated and converted to Krebs cycle intermediates

lipids

can be converted to Kreb cycle intermediates

glycogenolysis

breakdown of glycogen into glucose

absorptive state

occurs when digesting a meal

absorptive state

anabolic reactions occur, high levels of nutrients in the bloodstream

absorptive state

leads to storage molecules, getting nutrients into our body

postabsorptive state

long periods between meals cause this to occur

postabsorptive state

nutrient levels are low in bloodstream, leads to breakdown of storage molecules

postabsorptive state

catabolic reactions, occur when blood glucose is low

insulin

causes a reduction in blood glucose

insulin

released during the absorptive state, causes uptake of glucose by cells

insulin

promotes production of insulin, related to protein synthesis

glucagon

causes increase in blood glucose

glucagon

released during postabsorptive state, promotes glycogenolysis, gluconeogenesis, and lipolysis

sympathetic stimulation

low blood glucose levels cause ______ of adipose tissue

epinephrine

neurotransmitter used for sympathetic stimulation

epinephrine

can be released from the adrenal medulla

epinephrine

causes glycogenolysis and lipolysis to occur

liver

binds cholesterol to lipoproteins

cholesterol

fat soluble and cannot travel through the bloodstream freely, bound to lipoproteins

liver

produces very low density lipoproteins (VLDL)

LDL

carries cholesterol to cells

liver

85% of cholesterol is made by the

basal metabolic rate (BMR)

metabolic rate for life essential reactions

basal metabolic rate (BMR)

postabsorptive state, must be relaxed as possible, must be reclined

calorimeter and respirometer

two common ways to measure basal metabolic rate (BMR)

calorimeter

measured by lowering someone in water, measures heat generated

calorimeter

most accurate measure of BMR

respirometer

measures O2 consumed or CO2 produced using a respirometer

respirometer

indirectly measures energy expended

total metabolic rate (TMR)

occurs during activity, includes basal metabolic rate + the energy consumed to do activity

homeothermic

humans are warm-blooded, 37C

blood

our method of heat exchange is through the

heat

when hot, blood is sent to the surface to release

heat loss

when cold, blood is brought to the core to prevent

radiation

heat moves from hot to cold

conduction

when a transfer if heat occurs when two things come in physical contact (warmer object -> colder object)

convection

movement of heat due to air currents (warm air rises, cold air sinks)

evaporation

when a liquid converts to a gas, it takes heat with it

sensible water loss

occurs during sweating

insensible water loss

water loss due to things other than sweating, through breathing or urination for example

heat promoting mechanisms

1. vasoconstriction

2. increase metabolic rate

3. shivering

4. thyroxine release

5. behavioral mechanisms

vasoconstriction

decrease the flow of blood to the skin, heat loss is reduced

increase metabolic rate

nonshivering thermogenesis

adrenal medulla

secretes norepinephrine, causes an increase in cellular respiration

shivering

involuntary skeletal muscle contractions that produce heat

pilomotor response

contraction of arrector pili muscle makes hair stand up straight to trap warm air

thyroxine release

Babies and infants can release thyroid hormone to increase metabolic activity, lose this mechanism as you age

heat loss mechanisms

1. vasodilation

2. sweating

3. behavioral mechanisms

vasodilation

increase blood flow to the surface of the skin; increases heat exchange/loss at skin surface

sweating

activate certain glands to release fluid through our skin

inflammatory response

cells release pyrogens due to

pyrogens

cause the hypothalamus to release prostaglandins

prostaglandins

reset the internal thermostat

fever

vasoconstriction and shivering result, body temperature increases

hypothermia

being used in medicine to allow doctors more time to fix things at a slower pace. The body is then warmed to the appropriate temperature.

hyperthermia

can destroy cancerous tumors, beam intense heat at tumor to burn it

hypothalamus

major regulator of body temperature, acts through medulla and pons

metabolic activity

Major mechanism to generate heat for bodies is

non shivering thermogenesis

Norepinephrine causes increase in cellular respiration