Nervous system Flashcards
Name the two parts of the nervous system
Peripheral nervous system
Central nervous system
What is the role of a sensory neurone?
Sends impulses from the peripheral sense organs to the central nervous system
Name the two organs found in the central nervous system
Brain and spinal cord
Describe the role of the myelin sheath of Schwann cells
Electrical insulation. Allows the impulse to jump between nodes of Ranvier.
Describe the role of the axon in a motor neurone
Sends electrical impulses from the central nervous system to the muscles and glands (effectors)
Give the role of the central nervous system in a reflex
Processes information
Name the ion that enters the axon when a nerve impulse is transmitted.
Sodium ions
Which part of the axon has a positive charge as a nerve impulse passes?
The cytoplasm is more positively charged than the outside of the cell
Which part of the axon has a positive charge when an impulse is not generated?
The outside of the membrane is more positively charged than the inside of the cell
List the correct order of neurones in a reflex arc
Sensory neurone
Relay neurone
Motor neurone
What is a synapse?
A physical gap between neurones
Name a neurotransmitter
Acetylcholine
Describe how a synapse allows an impulse to cross
An impulse arrives at the pre-synaptic membrane
Calcium ions enter the pre synaptic knob
Vesicles containing neurotransmitter fuse with the membrane
Neurotransmitter is released into the synapse and diffuses to the post synaptic membrane.
Neurotransmitter binds to a receptor
Sodium ions enter the post synaptic knob and an impulse is r=created
Name the enzyme used to break down the acetylcholine
Cholinesterase
How is the merging of impulses prevented at a synapse
Calcium ions are actively transported out of the pre-synaptic knob
Cholinesterase breaks down the neurotransmitter
Neurotransmitter molecules are reabsorbed
