Thermoregulation Flashcards
What happens if body temp is too high
- sweat glands release onto skin surface
= sweat evaporates
= takes heat energy away with it
= cools body down - blood vessels vasodilate
= more heat energy transferred to surroundings
What is flushing
When body temp too high body flushes
- blood vessels get wider
- more blood flows through capillaries
- heat can transfer out of blood
= return to normal temp
What happens if body temp too low
- blood vessels containing capillaries constrict
= less blood flow near surface
= less heat energy lost to surroundings - muscles contract
= produces a lot of energy from respiration
= a lot of chemical reactions take place
= result in a lot of heat energy produced as waste
What is shivering
- skeletal muscles contract to release heat
What’s the endocrine system
- consist of glands which secrete hormones directly into bloodstream
Compare endrocrine vs nervous system
Nervous
- faster signalling
- uses electrical impulses which travel down neurones
Endocrine
- uses hormones which are chemicals carried in the bloodstream
Pancreas function
Release hormones
- control concentration of glucose in blood
Ovaries and testes function
Release hormones
- involved in puberty and reproduction
Thyroid gland function
Produce hormones
- involved in growth and regulate body’s basal metabolic rate
Adrenal glands function
Release hormone adrenaline
- produced in fear or stress
Pituitary gland function
Release hormones into blood depending on conditions
- act on other glands
- trigger range of different effects on the body
What controls glucose concentration in blood
- pancreas monitors blood glucose concentration
- releases insulin if too high
Insulin function
Triggers body cells to take up glucose from blood
- also triggers liver and muscle cells to store excess glucose
= means glucose concentration returns to normal
What happens to type 1 diabetes
Pancreas doesn’t produce enough insulin
Describe type 2 diabetes
- body cells no longer respond to insulin produced by the pancreas - the person still makes insulin but their cells are resistant to it and don’t respond as well as they should
- treated with balanced diet and exercise
- obesity is a large risk factor
What happens if blood glucose too low
- pancreas releases glucagon
- triggers liver cells to convert glycogen stores back to glucose
- then glucose released into blood
= return to normal
Adrenaline function
- increase heart rate
= more oxygen and glucose delivered in the blood to the brain and muscles
= prepares body to either fight or run away
Where is the thyroid gland
Base of the neck
= produce thyroxine
What happens when thyroxine levels fall
(Negative feedback cycle)
- pituitary gland releases TSH into the bloodstream
= triggers thyroid gland to release more thyroxine into the blood
= increased level of thyroxine detected by the brain
= prevent pituitary gland from releasing TSH
= thyroid gland releases less thyroxine
Why we need to maintain body temp
Maintain temp that enzymes work best
Prevent damage to cells/ enzymes
How are hormones transported
Blood plasma
How does the decaying process warm things up
Microorganisms respire
Respiration releases thermal energy
Why urine on hot day has high concentration of mineral ions and urea
- more sweating on hot day
- more water loss by sweating
- more water reabsorbed by kidney
= lower volume of urine
Define a hormone
Chemical messenger
How does the body keep constant temperature
- temp receptors in thermoregulatory centre
- TC detects core body temp
- temp receptors in skin send impulses to TC= give info about skin temp
- if core body temp too high
= skin capillaries dilate
= more blood flows and more heat lost - sweat glands release more sweat to cool body by evaporation
- if core body temp too low
= blood vessels constrict
= reduce blood flow
= less heat lost - muscles can shiver to release heat energy
Perfect temp of internal body
37 deg
= best for enzymes to work
How to decrease body temp
Blood vessels supplying capillaries dilate
= more blood through skin leads to greater heat loss
Reason for increase core body temp
Increase in respiration
= releases energy as a waste product
Reasons for decreased skin temp
Sweating
= evaporates and cools the skin
Why is there increase of skin surface temp
Vessels supplying skin capillaries dilate
= more blood flows nearer to surface of the skin
= more heat lost
How does body react to low blood sugar levels
Pancreas detects low blood glucose
= produces glucagon
= glucagon converted into glucose
Why happens to amino acids that can’t be stored
Amino acids broken down to form urea in the liver
Urea filtered by kidney and stored in bladder
How does thermoregulatory centre send info to sweat glands in the skin
Via neurones
Why more water lost through breathing
more energy needed
= more respiration
= increased breathing
