Chapter 13- Nervous System Flashcards
Components of nervous system; job ; fucyions of different neurones; relation between receptors,the cns,the spinal nerves and effectors; reflex action
Role of nervous system
Controls the Activities of the body and how it reacts to the surrounding
Stimulus
Any change in the environment that causes an organism to react is called a stimulus.
Response
An organisms reaction to a stimulus
Nervous system consists
- brain
- spinal cord
- spinal nerves
- hughly soecialosrd sense organs
What do sense organs d⁷o
. Help body to adjust to stimulus
. Enable various parts of body to coordinate with one another quickly
Involuntary actions
Automatic and not controlled
. Heart beat
. Breathung
. Peristalisis
Voluntary actions
Controlled consciously
Components of nervous system
CNS: brain nd spinal cord
PNS peripheral cranial :(nerves from brain) spinal nerves( from spinal cord) and sense organs
How nervous system works
- Sense organs receive stimulus: receptors
- Through electrical impulses: nerve impulses, receptors inform CNS of any change in surroundings
- Nerve impulses are transmitted to CNS by nerves
- Muslces: Effectors rsspond to the processed stimulus
Things by
•brain
•spinal cord
°voluntary action by geneeating nerve inpulses
°controls cranialreflexes e.g. salivation
° transmits nerve impulses to nd from the brain
°controls spinal reflexes e.g. knee jerk reflex
Cranial nerves
Sensory nerves transmit impulses ftom receptors to brain
Motor nerves transmit impulses from brain to effectors
Spinal nerves
- Sensory nerves transmit impulses from receptor to spinal cord
- Motor nerves transmit impulses from spinal cord to effectors
Nervous tissue
It makes the nervous system. Consists of nerve cells called NEURONES.
Sensory neurone
Receptor neurone
Transmits nerve impulses from the sense organs or receptors to the cns
Motor neurones
Effectors neurones
Transmits nerve impulses from CNS to the effectors
Relay neurone
Intermediate neurone
Transmits nerve impusles from sesnsory neurone to motor neurone. Found with in CNS
Nerve fibre
Strand of cytoplasm extending from cell body
Dendron
A nerve fibre that transmits impulses towars the cell bodyof a neurone
Axon
Nerve fibre that transmits nerve impulse away from cell body