topic 5,6 Flashcards
what is homeostasis
maintaining a stable internal environment
negative feedback
when the body senses something is too low or too high so to counteract does the opposite to reach a desired level
order which the nervous system kicks in
stimulus receptor sensory neurone cns motor neutron effector response
synapses
gaps between the nerves
the nerve signal is transferred by chemicals
reflex
stimulus sensory neurone relay neurone motor neurone effector
glands
pituitary gland - produces many hormones, called the master gland
thyroid - produces thyroxine to regulate rate of metabolism, heart rate and temp.
adrenaline gland - produces adrenaline for fight or flight
the pancreases - produces insulin to regulate blood glucose levels
controlling blood glucose
the pancreas’s detects a rise in glucose, so responds by secreting insulin into the bloodstream. insulin causes cells to take up more glucose from the blood and to store it as glycogen.
when levels are too low, glucagon is released into the blood. this does the opposite of insulin and causes glycogen to form into glucose.
hormones
hormones are chemical messenger which travel in the blood to activate target cells
type 1 diabetes
a condition where the pancreas doesn’t produce or doesn’t produce enough insulin
type 2 diabetes
when a dude becomes resistant to their own insulin
kidneys
kidneys filter the blood and substances removed are urea and urine
adh
the brain monitors the water levels within bloodstream. when it’s too low the pituitary gland releases adh so the kidney tubules become more permeable and more water is reabsorbed.
stages of menstrual cycle
stage 1 - uterus lining break down for 4 days
stage 2 - lining of uterus builds up again from day 4 to 14
stage 3 - egg is released from ovary at day 14
stage 4 - the wall is maintained for about 14 days until day 28
hormonal interaction in the menstrual cycle
FSH is produced in the pituitary gland and causes the egg to mature and stimulates ovaries to produce oestrogen
oestrogen stimulates growth of uterus and stimulates release of LH. stops FSH
LH made in pituitary, stimulates release of egg
progesterone produced by the ovaries to maintain the lining.
contraceptives
skin patches implants the pill barrier methods - condoms intrauterine devices ( T-shaped device) surgical methods natural methods
ivf
maturation of multiple eggs stimulates
eggs collected then from the ovaries
fertilised
eggs grow into embryos
one or two transferred into the woman’s uterus.
auxin
a plant hormone at the tip of a root or shoot. responsible for phototropism and gravitropism. also used to kill weeds and help grow cuttings
giberellins
controlling dormancy
inducing flowering
growing larger fruit
ethene
speed up ripening
gametes
sperm and egg
gametes ate made through meiosis
meiosis
chromosomes line up in pairs
cells pulled apart so that two cells have one copy of each chromosome
pulled apart again to them produce 4 gametes
mendel
monk who liked gardening. experimented with peas. crossed short pease with tall ones. all 4 offspring were tall.
crossed two tall peas. made 3 tall and 1 short
genetic engineering
to transfer a gene for a characteristic from one organism into another organism so that it has the characteristic
interdependence
all species rely on each other. if one goes this effects the entire ecosystem
