nervous system ! Flashcards
role of nervous system !
allows organism to detect changes in their surroundings & respond to it
enables coordination of different parts of body
components of nervous stem !
central nervous system (CNS) : brain, spinal cord
peripheral nervous system (PNS)
- cranial nerves : branch from brain
- spinal nerves : branch from spinal, cord
- sense organs
neurone !
basic functional units of nervous system
generate nerve impulses : quickly transmit information over long distance to other nerve cells
- sensory neurone
- motor neurone
- relay neurone
sensory neurone !
conducts nerve impulses from receptor to CNS
motor neurone !
conducts nerve impulses from CNS to effector
relay neurone !
transmit nerve impulses from
- sensory neurone -> brain
- brain -> motor neurone
- sensory neurone -> motor neurone
form synapses with sensory & motor neurones
synapse !
junction/connection between 2 neurones
reflex action !
involuntary response
immediate response to a specific stimulus w/o conscious control
reflex arc !
shortest pathway of nerve impulses from receptor to effector
spinal reflexes
controlled by spinal cord
- knee-jerk reflex
cranial reflexes
controlled by brain w/o person’s consciousness
- pupil reflex
- blinking
- salivation
process !
e.g : heat
heat stimulates receptors in skin -> nerve impulses produced -> transmitted along sensory neurone to spinal cord
in spinal cord : nerve impulses transmitted across synapse to relay neurone -> across another synapse to motor neurone
relay neurones transmit nerve impulses to brain -> brings about sensation of pain
relay neurone transmit nerve impulses to motor neurone -> transmit nerve impulses to effector
effector muscle : contracts -> withdrawal of hand from hot object
