homeostasis Flashcards
what is a reflex arc
the neural pathway which controls a reflex
whats a reflex
a rapid response to a stimulus without using the brain
whats the order of a reflex arc?
stimulus -> receptor -> sensory neurones -> relay neurones -> motor neurones -> effectors -> response
name the different parts of the brain
cerebral cortex, cerebellum, medulla, hypothalamus, pituitary gland, spinal cord
what are the 3 ways of studying the brain?
studying brains of those with brain damage, mri scans, and electrical stimulation.
why do we need to maintain water levels?
too much water in blood -> cells swell as water moves into them (due to conc gradient) -> cells burst / lysis.
too little water in blood -> cells lose water by osmosis -> cells dehydrate -> cell death
what is the endocrine system?
a group of glands which produce and secrete hormones (chemical molecules)
what are the 6 glands in the endocrine system, what do they produce and why
pituitary gland-hormones, to regulate body conditions. thyroid- thyroxine, rate of metabolism, heart rate and temperature. adrenal gland- adrenaline, can stimulate the body’s fight or flight mode. pancreas- insulin, glucose levels.ovaries- oestrogen, menstrual cycle. testes-testosterone, controls puberty and sperm production.
what happens on a hot day? body temp conditions + explain them in notes
hairs lie flat, vasodilation, sweat
what happens on a cold day? explain in notes too
muscles contract, vasoconstriction, hairs stick up
what are the differences between glucose, glucagon, and glycogen?
glucose - sugar. glucagon - hormone which increases blood levels . glycogen - the way we store glucose after eating.
what do the kidneys do?
act as a filter to help clean the blood
describe how excess amino acids is excreted from the body
amino acids -> ammonia -> urea -> urine
whats the name of the process where excess amino acids are converted into ammonia
deamination
when does the pituitary gland release ADH?
when water levels are low and blood is too concentrated.
what does ADH do?
helps increase water levels, as it causes kidney tubules to become more permeable and reabsorb h20.
what is a difference between type 1 and 2 diabetes?
type 1 - doesn’t produce much or any insulin. type 2 - insulin is still produced, but the person’s body is resistant to it and cell’s don’t respond to it
describe the menstrual cycle phases
uterus lining sheds, egg is matured and uterus lining is rebuilt, egg is released, then uterus lining is maintained
what’s the role of each hormone in the menstrual cycle?
fsh- matures egg. oestrogen- builds lining. lh- releases egg. progesterone- maintains uterus lining
how can hormones in a pill help to reduce fertility?
pills can contain oestrogen and progesterone. oestrogen inhibits the release of fsh, stopping egg development and production overtime. progesterone- by stimulating the production of thick mucus, stopping sperm from getting through and reaching the egg
what is IVF?
fertilisation happening outside the human body
what is a tropism?
growth in response to a stimulus
which way do shoots and roots grow to gravity and light?
shoots grow towards light and away from gravity. roots grow away from light and towards gravity
what happens in the eyes when focusing on a close object?
the lens becomes thicker and more curved and light is refracted more, the ciliary muscles contract, the suspensory ligaments loosen, need a convex lens
