B3.3 Maintaining Internal Environments Flashcards
body at 37C
ideal body temp
enzymes most efficient
body at 35C
enzymes too slow
respiration releases not enough energy
die from hypothermia
body at 40C
because of illness or external heat
enzymes could denature stopping some body processes
how is body temperature controlled
receptors detect external/internal stimuli
signal sent to thermoregulatory centre in brain
brain sends signal to appropriate effector
body stays normal - homeostasis
when it is too hot
body hair flatten (no insulation)
sweat glands secrete sweat to transfer energy out of body
vasodilation in capillaries that appear near skin to allow heat loss through radiation
when it is too cold
body hair stands up (insulation)
vasoconstriction to minimise heat loss
shivering (rapid muscle contractions) for more respiration to release more energy to heat up
high blood sugar levels (hyperglycemia)
damages blood vessels and nervous system
low blood sugar levels (hypoglycemia)
get tired quickly due to lack of respiration
hyperglycemia
pancreas detects sugar level is too high
insulin is secreted which stimulates liver
liver now turns glucose into glycogen through enzyme-controlled reactions
glycogen is now stored in liver
hypoglycemia
pancreas detects sugar level as too low
glucagon is secreted which targets liver
liver now turns stored glycogen into glucose through enzyme controlled reactions
glucose is released into blood
Type 1 Diabetes
when immune system has destroyed pancreatic cells that produce insulin
begins in childhood
countered by insulin injections, balanced diets and regular exercise
Type 2 Diabetes
when the body cells do not respond properly to insulin causing it to be less effective
happens in later life and linked to obesity
need to manage carb intake and exercise levels and encouraged to lose weight
some cases: drugs used to stimulate insulin production or insulin shots used
