The nervous system (coordination and control) * Flashcards
What are sensory receptors?
they detect stimuli and initiate responses to them
What is the CNS?
(four points)
the Central Nervous System
it is where information from the receptors is sent, and where reflexes and actions are coordinated
includes the brain and spinal chord
What are effectors?
muscles or glands that respond to nervous impulses and bring about a response to the stimulus
What do sensory neurones do?
they carry information (electrical impulses) from the receptors to the CNS
What do relay neurones do?
they carry electrical impulses from sensory neurones to the motor neurones
Where are relay neurones found?
in the CNS
What do motor neurones do?
they carry electrical impulses from the CNS to the effectors
What is the structure of a sensory neurone?
- receptor cells connected to end of dendron
- one long dendron -> carries impulse from receptor to cell body
- cell body located in the middle of the neurone
- one short axon -> carries impulse from cell body to CNS
What is the structure of a relay neurone?
- many short dendrites -> carries impulse from CNS to cell body
- cell body located near the start/middle of the neurone
- one axon -> carries impulse from cell body to motor neurones
What is the structure of a motor neurone?
- many short dendrites -> carries impulse from CNS to cell body
- cell body located at the start of the neurone
- one long axon with a myelin sheath -> carries impulse from cell body to effector
What is a myelin sheath?
an insulating layer that allows electrical impulses to transmit quickly and efficiently - the impulse ‘jumps’ between gaps
What is the synapse?
the gap between two nerves
What happens at the synapse? - fill the gaps :
1 the _______ travels into the _______ _____
2 the ________ _______ move down to the end of the ______ and release ______________
3 _____________ ________ enter the receiving _______ by binding to _______ sites
5 the _____________ ________ / _______ travel through the receiving ______
1 the impulse travels into the synaptic bulb
2 the synaptic vesicles move down to the end of the neurone and release neurotransmitters
3 neurotransmitter molecules enter the receiving neurone by binding to receptor sites
5 the neurotransmitter molecules / impulse travel through the receiving neurone
What is the cell body?
contains the nucleus an organelles in cytoplasms
What are dendrites?
tiny branches at the start of a sensory neurone where the impulse from the receptor cell arrives
