section 6 - coordination and response Flashcards
what do receptors do
detect stimuli from changes in environment
what do effectors do
response to stimuli - include muscle cells and cells found in glands
what are neurones
nerve cells
what are 3 main types of neurone
sensory, relay, motor
what does the CNS consist of
brain and spinal chord
how do neutrons transmit information
high speed impiulses and rapid responses
what is the connection between 2 neurone called
synapse
what are the chemicals called that transfer nerve signals
neurotransmitters which diffuse across the gap
what to the chemicals set off
a new electrical signal in the next neurone
what is an example of a reflex
bright light causing ur pupils to get smaller. blinking
describe the reflex arc
stimulus detected by receptors causes and electrical impulse to be sent along a sensory neurone to CNS. in the CNS the sensory neurone passes to relay neurone to the motor neurone to the effector. it is quicker than a normal resp[onse
what is the conjunctive for
protects the eye
what is the function of the cornea
refracts light into the eye
what is the iris for
controls diameter of the pupil and how much light enters the eye
what is the lens for
focuses the light onto the retina
fovea
blind spot
what is the retina for
captures the light
what does the optic nerve do
carries impulses from the receptors to the brain
at happens in bright lite
circular muscles contract, radial muscles relax and the pupils constrict
what happens in dim light
circular muscles relax, radial muscles contract causing the pupil to dialate
what is changing the shape of the lense called
acommodation
what happens at distant objects
cililary muscles relax, suspensory muscles pull tight, lens goes thin and less curved so refracts light by smaller amount
what happens with near objects
ciliary muscles contract, suspensory ligaments slacken. lens becomes fat and more curved which increases the amount of light it refracts
what happens to eyes as you get older
lens loses flexibility so cant easily spring back to round shape which means light can’t be focused well for near viewing.
what happens with short sighted people
unable to focus on distant objects. cornea or lens bends the light to much or eyeball is so long. distant objects are bought into focus in front of the retina
what happens with long sighted peopel
unable to focus on near objects. cornea or lens doesn’t bend the light enough oor eyesball is to short. the images of near objects are brought into focus behind the retina
what are 3 differences between nerves and hormones
- nerves are fast, hormones are slow
- nerves act for a very short time hormones act for long time
- nerves are a precise area, hormones are in a general area
what is source, role and effect of adrenaline
adrenal glands, fight or flight response, increases heart rate and blood flow to muscles
what is source, role and effect of insulin
pancreas, controls blood sugar level, stimulates liver to turn glucose into glycogen for storage
what is source, role and effect of testosterone
testes, main male sex hormone, promotes male secondary characterists
what is source, role and effect of progesterone
ovaries, supports pregnancy, maintains lining of uterus
what is source, role and effect of oestrogen
ovaries, main famale sex hormone, controls menstrual cycle and promotes female secondary characteristics
what is source, role and effect of ADH
pituitary gland, controls water content, increases permeability of collecting duct
what is source, role and effect of FSH
pituitary gland, female sex hormone, causing egg to mature in ovary, stimulates the ovaries to produce oestrogen
what is source, role and effect of LH
pituitary gland, female sex hormone, stimulates release of an egg from ovary
what is homeostasis
the maintenance of a constant internal environment
3 ways water is lost
- skin as sweat
- lungs as break
- kidney as urine
what happens if you are to hot
- sweet produced, when evaporates it transfers energy from skin to environment
- blood vessels close to the surface of the skin widen - vasodilation allowing more blood near surface so it can transfer more energy to surroundings
- hairs lie flat
what happens when your cold
- little sweat is produced
- blood vessels near the surface of the surface constrict - vasoconstriction. less blood flows near the surface so less energy is transferred to surroundings
- shiver increases rate of respiration which transfers more energy to warm body
- hairs stand on air to trap an insulating layer of air which keeps you warm
why do seller organisms cool faster
bigger SA:V ration so loose heat faster
hoe fo animals in cold conditions reduce heat loss
have compact shape to keep SA to a minimun
what are auxins
plant growth hormones which control growth at tops of shoots and roots
what are shoots called if they grow toward the light
positive phototrophic
what happens when a shoot tip is exposed to light
accumulates more auxin on the side thats in the shade than in the light. this makes the cells elongate faster or the shared side so the shoot bends towards the light
what are shoots that grow away from gravity called
negatively geotrophic
what happens when a shoot is growing sideways
gravity produces an unequal distribution fo auxin in the tip with more auxin on the lower side. this causes the lower side to grow faster, bending the shoot upwards
the name when roots grow towards gravity
positively geotropic
what’s the name when roots grow away from light
negitively phototrophic
what happens when roots grow sideways
more auxin on lower side. root with extra auxin inhibits growth. the cells on top elongate faster and the root bends downwards.
what happens when root is exposed to light
more auxin accumulate on more shaded side. auxin inhibits cell elongation on the shaded side so the root bends downwards, back into the ground. roots that are underground aren’t exposed to light so they grow downwards due to positive gravitropism
