Page 51 - PRE-U STPM BIOLOGY TERM 1

Biology Term 1 STPM Chapter 2 Structure of Cells and Organelles

synaptic knobs.
5. There are three types of neurones namely the motor, sensory and
associative neurones.
(a) Motor neurone
Motor neurone transmits impulse from the central nervous
system to the effector i.e. muscle or gland. Its structure is as
2 shown in Figure 2.47.
Dendron

Axon Nerve impulse Myelin sheath

Cell body Node of Ranvier Nucleus of Schwann Effector

Figure 2.47 Structure of a motor neurone
(b) Sensory neurone
Sensory neurone transmits impulse from the receptor to the
central nervous system.
Dendron Nerve impulse Cell body
Nucleus

Receptor cell Axon Myelin sheath Synaptic knob
Figure 2.48 Structure of a sensory neurone
(c) Interneurone (associative / intermediate neurone)
Interneurone receives impulse from the sensory neurone and
transmits it to the motor neurone. It is found in the brain or
spinal cord. Some can generate impulse and others transmit
impulse from one to the other. It varies in shape, bipolar and
multipolar with one or more dendrons or axons.

Axon Nucleus Dendron Dendrits

Axon
Cell body
Dendrons
Bipolar

Multi-polar
Figure 2.49 Types of interneuron

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