homeostasis and response Flashcards
(30 cards)
what’s a nerve cell
adapted to carry electrical impulses from one place to another
how is a nerve cell adapted
long
th in
lots of branches
increase surface area
what is a synapse
a gap between neurones which chemical messengers diffuse across
what is the refelx arc cycle
stimulus
receptor
sensory neurone
CNS
relay neuron
motor neurons
effector
response
what is one way to remember reflex arc
SILLY
RABBITS
SEE
CONNIE
REALLY
MOVING
EVERY
RESPONSE
6 marker about hot pans
The heat stimulus is detected by temperature receptors in the skin
electircal impulse carried from the sensory neurone to the CNS
chemical transmission across synapse
via relay neurone
electrical impulse carried from motor to the effector
muscle contracts moving the hand away
what are all diffrent parts of the brain and what do they do
cerebral cortex( big bit)
controls consciousness, memory, senses, language, intelligence
cerebellum
bottom right
controls coordination and balence
medulla (long tail)
controls unconcious activity’s (e.g breathing)
hypothalamus (regulate body temp)
what are some ways that scientists study the brain
study people with brain damage
electrically stimulate diffrent parts of the brain
scan
why is treating the brain so difficult
wide range of things that could go wrong
brain is so complex and hard to understand
brain tissue is fragile
what does each part of the eye do
Iris - controls size of the pupil
Lens- Can change its shape to controls light refraction
retina -
optic nerve- impulses generated by receptor cells
cornea- transparent and has no blood vessels
what does the eye do when it’s dark or light
dark = circular muscles relax and radial muscles contract
light= radial muscles relax
circular muscles contract
describe oral contraceptives (e.g pill)
it’s hormonal
prevents the body from producing FSH( hormone that causes egg to mature)
advantage - highly effective if taken correctly
disadvantage- must remeber to take it everyday
may have side effects
doesn’t protect against STIS
describe implant, injection , skin patch
hormonal contraception
contains progesterone that stops egg from maturing or being released
advantage - more convinuent that taking a daily pill
disadvantage- dosent protect against STIS
explain barrier method of contraception ( condom)
non hormonal
prevents the sperm from reaching the egg as it acts as a barrier
advantage- protects against STIS
no side effects
disadvantage- may break
not entirely effective
explain spermicide
kills sperm
explain IUD (coil)
hormonal
prevents embryo from implanting
releases hormones to reduce chances of fertilisation
advantage- highly effective
lasts a long time
disadvantage- does not protect against STIS
explain sterilisation
surgical method of conraception
women- prevents egg from reaching the uterus
men - prevents sperm from leaving the penjs
advantage
highly effective
disadvantage- hard to reverse
doesn’t protect against STIS
explain abstinence
natural form of contraception
not having sexual intercourse when the woman is ovulating
disadvantage- hard to tell when a woman is ovulating
doesn’t protect against STIS
Why are contraceptions controversial
Catholic church teaches that all contraption exempt natural ones are unethical
other people believe it’s their right to choose and condoms actually reduce the risk of STIS
what does FSH do
hormone that trigger egg to mature
what does LH do
triggers the mature egg to be released
what is the process of IVF
happens in labs
1) mother is treated with FSH and LH
2) causes several eggs to mature
3) collects egg from mother
4) collects sperm with father
5) fertiles them
6) fertilised eggs turn into embryos
7) embryos are inserted into mothers uterus
what are some problems with IVF
success rates aren’t that high
emotionally and physically stressful
can lead to multiple births
unethical - embryos that aren’t transferred are destroyed
people believe they are killing human life and others believe it’s just a ball of cells.
what is the stem response to light stimulus
positive phototropism
bends towards the light
