B3.3 - maintaining internal environments Flashcards
what temperature may you have a risk of hypothermia by?
35°C
how does exposure to extreme cold affect the body?
- core temperature may reduce
- causes enzyme reactions to occur too slowly
- respiration does not release energy fast enough
- cells begin to die
what does exposure to high temperature lead to?
- body overheats
- enzymes may denature
- body reactions cannot occur
state a key fact about homeostasis
it is a negative feedback loop
what area in your brain is responsible for regulating body temperatures?
- thermoregulatory centre
hypothalamus
what is a change in temperature detected by?
- skin receptors (external temperature)
- internal receptors (blood temperature)
what does a change in temperature result in?
the brain sends impulses to effectors
what happens when you get too hot?
- body hair lowers
- vasodilation
- sweat glands produce sweat
how does body hairs lowering cool you down?
prevents layer of insulating air being trapped around body
how does vasodilation cool you down?
- increases blood flow to capillaries (surface of skin)
- increasing heat loss via radiation
how does sweating cool you down?
- water in sweat evaporates
- energy is transferred by heating from body to environment
what happens when you get too cold?
- body hairs rise
- blood vessels = vasoconstriction
- shivering begins
how does body hair rising keep you warm?
- traps a layer of insulating air close to the skin
how does vasoconstriction keep you warm?
reduces blood flow through the capillaries (less heat lost)
how does shivering keep you warm?
- occurs when your muscles contract and relax quickly
- cells respire more quickly
- transfer extra energy by heating
what are the effects on the body if blood glucose levels are too high?
- affects concentration gradient in blood (negative impact on osmosis)
what are the negative effects on the body of blood glucose levels are too low? - not conc. gradient
- organism cannot produce enough energy
- prevents cell from respiring effectively
describe what happens when you eat food
1) glucose released by digestion passes into bloodstream
2) blood sugar levels rise
what happens when blood glucose levels are too high? - body’s response
- pancreas detects change
- releases (hormone) insulin
- insulin travels in blood to liver
- liver is stimulated to turn glucose into glycogen
- glycogen stored in liver
what happens if blood glucose levels are too low? - body’s response
- pancreas detects change
- releases glucagon (hormone)
- hormone makes liver change glycogen into glucose
- released into blood
what causes blood sugar levels to drop?
exercise (glucose used more during respiration)
what is the difference between glycogen, glucose and glucagon?
- glucose is released during digestion (sugar)
- glycogen is glucose stored in the liver
- glucagon is the hormone released by the pancreas to stimulate glycogen to be changed into glucose
Which organ helps to restore our glucose levels to normal when they fluctuate?
liver/pancreas
what does insulin do?
- bind to cells in body
- tells them to absorb excess glucose and turn it into glycogen
causes of type 1 diabetes
- Cannot produce insulin or very little insulin produced
- Immune system has destroyed pancreatic cells that make insulin
causes of Type II diabetes
- Cells do not produce enough insulin
- cells do not respond properly to insulin (may be resistant)
- cells won’t take in glucose from bloodstream
how is type 1 diabetes controlled?
- injecting insulin
how is type 2 diabetes controlled?
- healthy, low sugar diet
- regular exercise