Download 10.2 Neurones

10.2 Neurones
AQA A2 2011 ad
Learning objectives:
Name and give location of the three types
of neurones.
Relate the structure of the neurone to its
function.
Structure of neurone
Cells specialised for rapid transmission of electrical impulses.
Consist of
Cell body: contains large nucleus, large amount RER for
protein and neurotransmitter production
Dendrons: extensions of the cell body subdivided into
dendrites carrying impulses to the cell body
Axon:long fibre carries nerve impulses away from cell body
Schwann cells: wrap round axon with many layers of
membrane, providing electrical insulation. Phagocytic
removing cell debris and involved in nerve regeneration.
Myelin sheath: axon covering made of the membranes of
Schwann cells. Membranes rich in lipid myelin. Myelinated
axons transmit impulses faster than non-myelinated axons.
Nodes of Ranvier: 2-3µm gaps every 1-3mm between
Schwann cells where there is no myelinated sheath
Neurones
Motor neurone
Sensory neurone
Intermediate neurone
Summary
Neurones are adapted to carry electrochemical
changes called (1). Each neurone comprises a cell
body that contains a (2) and large amounts of (3),
which is used in the production of proteins and
neurotransmitters. Extending from the cell body is a
single long fibre called an axon and smaller branched
fibres called (4). Axons are surrounded by (5) cells,
which protect and provide (6) because their
membranes are rich in a lipid called (7). There are
three types of neurone. Those that carry nerve
impulses to the effectors are called (8) neurones.
Those that carry impulses from a receptor are called
(9) neurones and those that link the other two types
are called (10) neurones.
1. Nerve impulse/action potential
2. Nucleus
3. RER
4. Dendrites
5. Schwann cells
6. Insulation
7. Myelin
8. Motor
9. Sensory
10. Intermediate