2j coord and response Flashcards
define homeostatis
maintaneince of a constant internal environent = body water content and temp
describe the process of synapses
- electrical impulse travels along axon
- triggers nerve-ending of nuerone to release the chemical messengerss = neurotransmitters
- neurotransmitters diffuse across synape and bond w receptor molecules on next neruone
- receptor moleucles bidn only to the specific neurotransmitters released
- stimulates the recieving neurone to transmit the electrical ip
optic nerve
carries the impulse from retina to brain
retina
made up of light sensitive reeptor cells = rode and cone cells
convert light –> electrical energy
rod cells
sensitive to low light intensity
MORE sensitive > cones
cone cells
sensitive to colour
sclera
tough outer layer of eye
protects eye and holds it in place
cornea
-transparent sclera at the front
- refracts light, bending it to enter the eye
iris
- has a set of muscles that control the size fo the pupil
- regulates amnt of light reaching retina
cilliary + suspensory
- changes shape of lens to focus lightrays on retina
choroud
- underneath sclera
- dark layer contains pigment cells + bv which stop light from being reflected aorund inside
fovea
centre of retina, highest cones conc
blidn spot
no rods and no cones
lens
focuses light rays on retina
pupil
hole in the iris
allows light to pass through
where does light refraction to form an image hapoens?
cornea
lens
iris reflex, DIM LIGHT
- circular muscles relax
- radial muscles contract
= dialation
iris reflex, NRIGHT LIGHT
- circular msucles contract
- radial msucles relax
= contraction
accomadation, CLOSE
- cilliary muscles contract –> choroid towards lens
- susnpesnoary ligaments relax
- lens thicker
accomadation, FAR
- Cilliary muscles relax –>choroid away from lens
- suspensory ligamanets contral
- lens becomes flatter
what hormones released from pituitray?
FSH, ADH, LH
nervous characteristics:
response: rapid and precisie
nature: electrical, nerve impulse
action: carried to nerves to a specific effector
endocrine characteristics
response: slower, longer acting
nature: hormone, chemical
actoion: carried in blood to all organs, but affects target organ only
NEURONE TYPES
SENSORY: receptor –> CNS
RELAY: CNS
MOTOR: CNS –> EFFECTOR
REFLECX ARC
STIMULUS
RECEPTOR
SENSORY NEURONE
SYNAPSE
RELAY
CNS (SPINAL CHORD)
SYNAPSE
MOTOR
EFFECTOR
REPONSE
NEURONE ADAPTATIONS (..as a specialised cell)
- extended shape: impulses from long range
- fine branches (axon & dendrites terminal) to communicate w other neurones (during synapses)
-myelin sheath: electrical insulatir and ensures impulse stays in termnial, fatty mats and speeds up transmission.
ADRENALINE
source: adrenal glands
effects: increases HR, BR, BLOOD SUGAR, BLOOD FLOW TO MUSCLES
INSULIN
source: pancreas
effects: controls blood glucose levels, stimulates glucose to be stored as glycogen in the liver
TESTOSTERONE
source: testes
effects: male secondary sexual charcateristcs + sperm production
OESTROGEN
source: ovaries
effects: female secondary sexual charcatestics, thickens uterus lining
PROGESTORONE
source: ovaries
effects: preps uterus lining, maintains preganncy
ADH
source: pituitary
effects: controls water vol of urine, osmoregualtion, CD
FSH
source: pituitray
effects: cuases follicle to mature so ovulation, and produces oestrogen
LH
source: pituitary
effects: ovulation
