Nervous system Flashcards
What is the function of the myelin sheath?
It acts as insulation for the axon and dendron.
What is the node of Ranvier?
The node of Ranvier is the region where the myelin sheath is absent on an axon or dendron. As nerve impulses cannot be transmitted through the myelin sheath, they jump from one node to the next instead. This way, they help to speed up transmission of impulses along the nerve fibre.
What is the pathway of impulses during a reflex action?
Receptors in skin -> Sensory neurone -> Spinal cord -> Relay neurone -> Motor neurone
What is a synapse?
A synapse is a junction between two neurones/a neurone and an effector. It is the tiny space where impulses are transmitted from the axon of one neurone to the dendron of another neurone.
What does the grey matter and white matter consist of respectively?
The grey matter consists of cell bodies of neurones while the white matter consists mainly of nerve fibres.
What is the pathway of impulses during a voluntary action?
Forebrain -> Relay neurone in spinal cord -> Motor neurone -> Effector
