Temperature Regulation Flashcards
Nutrient pools
- are built up storage of nutrients (amino acids/carbs/fats)
- will form when a molecule is taken into the body, but is not needed for energy, growth, or maintenance
We can take glucose that is not needed at the moment and store it as glycogen
We can take amino acids and form structural or functional proteins
CO2 is waste, urine is waste
Pathways for interconversion
Gluconeogenesis
Glycogenolysis
Gluconeogenesis (Pathways for Interconversion)
The process of creating glucose or glucose derivatives from non-carbohydrate sources
- Proteins can be deaminated and converted to Krebs cycle intermediates
- Lipids can be converted to Krebs cycle intermediates
Glycogenesis (Pathways for Interconversion)
The breakdown of glycogen into glucose
Absorptive State
Occurs when digesting a meal
-Getting nutrients into our body
High levels of nutrients (like glucose) in the bloodstream
Anabolic reactions occur
-Leads to storage molecules
Postabsorptive State
Long periods between meals cause this to occur
Nutrient levels are low in the bloodstream
Leads to break down of storage molecules
-These are catabolic reactions
Occurs when blood glucose is low
What are major indicators to switch between absorptive and postabsorptive states?
Blood glucose levels in the body
Hormonal control
insulin
glucagon
Insulin (hormonal control)
Causes a reduction in blood glucose
Released during the absorptive state
-High levels of blood glucose cause the release of insulin
Causes an uptake of glucose by cells
The cells oxidate the glucose for energy
Promotes the production of glycogen
Also related to protein synthesis
Glucagon (hormonal control)
Causes an increase in blood glucose
Released during the postabsorptive state
-Low blood glucose levels stimulates the release of glucagon
Promotes glycogenolysis, gluconeogenesis, and lipolysis
Neural controls
sympathetic stimulation
epinphrine
Sympathetic stimulation (neural control)
Low blood glucose levels cause sympathetic stimulation of adipose tissue
-Brings fat out of storage
Breakdown of adipose tissue
- Causes an increase in energy production
- Occurs in the postabsorptive state
Epinephrine (neural controls)
Neurotransmitter used for sympathetic stimulation
Can be released from the adrenal medulla
Sympathetic stimulation of the adrenal medulla increases epinephrine levels in the blood
- Epinephrine acts on the liver and skeletal muscles to release glycogen
- Can act on adipose tissue to release material for energy
Causes glycogenolysis and lipolysis to occur
Role of liver in cholesterol regulation
The liver binds cholesterol to lipoproteins
The liver produces very low density lipoproteins (VLDL)
Low density lipoproteins (LDL) carries cholesterol to cells
85% of cholesterol is made by the liver
The liver binds cholesterol to lipoproteins (Role of liver in cholesterol regulation)
Cholesterol is fat soluble and cannot travel through the bloodstream freely
Cholesterol is bound to lipoproteins
-Lipoproteins act as carrier molecules
The liver produces very low density lipoproteins (VLDL)
Role of liver in cholesterol regulation
VLDL is converted to LDL in the liver
Low density lipoproteins (LDL) carries cholesterol to cells
Role of liver in cholesterol regulation
High levels of LDL leads to cholesterol build-up on the walls of blood vessels
As LDL delivers cholesterol to cells, LDL is converted to HDL
-HDL is high-density lipoproteins
Basal Metabolic Rate (BMR)
Metabolic rate for life essential reactions
Must be measured under certain conditions
Must be measured under certain conditions (BMR)
Postabsorptive state
-No eating 12 hours prior to testing
Must be relaxed as possible
Must be reclined
Two common ways to measure BMR
calorimeter
respirometer
Calorimeter (way to measure BMR)
Measured by lowering someone in water
Measures the heat generated in the water
-Measure the change in water temperature
Most accurate measure of BMR
RESPIROmeter (way to measure BMR)
Measures O2 consumed or CO2 produced using a respirometer
Indirectly measures energy expended
Total Metabolic Rate (TMR)
Occurs during activity
Include basal metabolic rate + the energy consumed to do activity
Describe how body temperature is regulated, and identify factors that increase/decrease body temperature.
Humans are warm-blooded (homeothermic)
Blood is our method of heat exchange
Our body is a balance of heat production and heat loss
Humans are warm-blooded (homeothermic)
Describe how body temperature is regulated, and identify factors that increase/decrease body temperature
Stable internal body temperature independent of the external environment
Humans stabilize around 37*C
Blood is our method of heat exchange
Describe how body temperature is regulated, and identify factors that increase/decrease body temperature
When hot, blood is sent to the surface to release heat
When cold, blood is brought to the core to prevent heat loss
- Radiation (heat exchange)
Heat always moves from hot to cold
-Heat leaves the body and moves to the colder external environment
- conduction (heat exchange)
When a transfer of heat occurs when two things come in physical contact
-Heat will be transferred directly from the warmer object to the colder object
- Convection (heat exchange)
Warm air rises, cold air sinks
Movement of heat due to air currents
- Evaporation (heat exchange)
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
-Losing water through breathing out
When you breathe out, water vapor is expelled
-Urination is another example of insensible water loss
Heat-Promoting Mechanisms
vasccontrcition increase metabolic rate shivering thyroxine release behavioral mechanism
Vasoconstriction
Heat-Promoting Mechanisms
Decrease the flow of blood to the skin
Heat loss is reduced
Body temperature increases
Increase Metabolic Rate
Heat-Promoting Mechanisms
Metabolic activity increases heat production
In adults, the adrenal medulla secretes norepinephrine
- Causes an increase in cellular respiration
- Creates heat
Non-shivering thermogenesis
Shivering
Heat-Promoting Mechanisms
Involuntary skeletal muscle contractions that produce heat
Pilomotor response
-Contraction of the arrector pili muscle makes hair stand up straight to trap warm air
Shivering thermogenesis
Thyroxine release (Heat-Promoting Mechanisms)
Babies and infants can release thyroid hormone to increase metabolic activity
-Metabolic activity increases heat
Lose this mechanism as you age
Behavioral mechanisms (Heat-Promoting Mechanisms)
If we lose heat at the surface of the body, we put on clothes
We can choose to become physically active to increase heat production
We can change posture
- Curling into a ball decreases the surface area in contact with the air
- Preserves heat
We can drink something warm to make the core temperature higher
Heat loss mechanisms
vasodilation
sweating
behavioral mechanisms
Vasodilation
Heat loss mechanisms
Increase blood flow to the surface of the skin; increases heat exchange/loss at skin surface
Sweating
Heat loss mechanisms
Activate certain glands to release fluid through our skin
Sweat glands release a watery secretion
Water on top of the skin can evaporate and carry heat away from the body
Behavioral mechanisms (Heat loss mechanisms)
We can stop being active to decrease muscle contractions
-This will decrease heat production
We can find a cool surrounding (go from sun into the shade)
We can lose more heat
wearing light/loose clothing
-Wearing light and loose clothing makes you cooler than being naked
We can wet the surface of the body by getting into a body of cool water
Mechanism for the generation of a fever.
Cells release pyrogens
-Typically due to the inflammatory response
Pyrogens cause the hypothalamus to release prostaglandins
Prostaglandins reset the internal thermostat
Vasoconstriction and shivering result
Body temperature increases
Hypothermia
exposure death
Body is in peril if the body temperature drops below 95*F
As body temperature decreases, shivering occurs to help increase body temperature
Shivering becomes uncontrollable
Shivering eventually stops, a person becomes sleepy and dies
Hyperthermia can ….
destroy cancerous tumors
Beam intense heat at the tumor to burn it.
More about hypothermia
is 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.
