Structure and Function of Neurones Flashcards
What are motor neurones?
Neurones that carry an action potential from the CNS to the effector.
What is a myelinated neurone?
Has an individual layer of myelin around it.
What is a non-myelinated neurone?
Has no individual layer of myelin
What are relay neurones?
Join sensory neurones to motor neurones.
What are sensory neurones?
Neurones that carry an action potential from the sensory receptor to the CNS.
Why are neurones long?
So that they can transmit the action potential over long distances.
What do dendrites do?
Carry impulses towards the cell body. Numerous dendrites connect to other neurones.
What does an axon do?
Carry impulses away from the cell body.
Neurones are surrounded by a fatty layer that insulates the cell form electrical activity in other nerve cells nearby. What is this fatty layer composed of?
Schwann cells.
What is the position of the motor neurones?
They have their cell body in the CNS and have a long axon that carries the action potential out to the effector.
What is the position of the sensory neurones?
Have a long dendron carrying the action potential from a sensory receptor to the cell body, which is positioned just outside the CNS. They then have a short axon carrying the action potential into the CNS.
What is the position of the relay neurone?
Relay neurones connect the sensory and motor neurones together. They have short dendrites and the number of divisions of the axon is variable.
What do relay neurones do?
Conduct impulses in coordinated pathways.
What are the gaps in the myelin sheath called?
The nodes of Ranvier
What does the myelin sheath do?
Prevents the movement of ions across the membrane so that it can only occur at the nodes of Ranvier.
