Nervous system Flashcards
What does the nervous system do?
coordinate behaviour
respond to surroundings
Use of neurons
carry electrical impulses
Neurones adaptations
many dendrites: connect to more, pass more msg
myelin sheath: insulates impulses, speeds up impulse conduction
what are synapses, how do they work
gap between neurones
neurotransmitters are released to pass electrical impulses in a chemical way
post- receptors synapse membrane doesn’t allow backflow of impulses
electric current triggered and is transmission is continued
possible problems with synapses
interfered by other imitating or blocking chemicals
v drugs to deal
3 types of neurones
sensory, relay, motor
components and uses of CNS
brain + spinal cord
take in sensory info, instruct body to work
flow chart from stimulus to response
stimulus → receptor cells → sensory neurone → CNS (relay neurone) → motor neurone → effector → respons
spine isnt the same as spinal chord
types of receptors
eyes (light), ears (sound), nose (chemical), pain, pressure (KE / chem), temperature (thermal)
what’s a reflex arc
it’s the nerve pathway that underlies our unconscious reflexes
rapid and automatic, involuntary
avoid danger, protect
how is a reflex arc different from a normal reaction
a reflex arc doesn’t involve the brain, only spinal cord
What is homeostasis
Maintenance of a constant internal environment
Body temp & water content
What does co-ordinated response require
Stimulus, receptor, effector
Function of lens
Change shape to bend light onto retina
Lens vs cornea in terms of light refraction
Cornea: refracts light in the same amount, x flexible
Lens: adjust amount of light refracted
Function of optic nerve
Neurones to carry impulse
Suspensions ligament isn’t a muscle
What’s special about the blind spot
There aren’t any cones or rods, x image forms
What is the fovea (spelling!)
Place where light should bend to
What are the 2 types of cells the retina contain
- Cone cells: works in bright light, sensitive to red, green, blue, found in fovea only
- Rod cells: works in dim light, only black and white, found all over the retina
A: vitreous humour
B: lens
C: cornea
D: pupil
E: iris (control pupil size)
F: sclera
G: optic nerves
H: choroid (spelling!)
I: aqueous humour
J: ciliary muscle
K: suspensory ligament (fibre)
L: fovea
M: blind spot
A: vitreous humour
B: lens
C: cornea
D: pupil
E: iris (control pupil size)
F: sclera
G: optic nerves
H: choroid (spelling!)
I: aqueous humour
J: ciliary muscle
K: suspensory ligament (fibre)
L: fovea
M: blind spot
