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STRUCTURE OF A NEURONE
Receptors are special nerve endings found within our skin and include: touch, pain, pressure and
temperature receptors. It is their job to detect changes in the environment. These changes, known as
stimuli may include temperature changes, pain or pressure, are carried in the form of electrical
impulses from the receptors along the Peripheral Nervous System (PNS) to the Central nervous
System (CNS) of the spinal cord and finally to the Brain. The electrical impulses travel through the
nervous system via neurones.
Neurones are the basic cells of the nervous system. There are three different types of neurones:
NEURONE
Sensory neurone
Inter neurone
Motor neurone
FUNCTION
Carry the impulse generated by the stimuli to the Central Nervous System
(CNS)
Carry the impulse through the Central Nervous System (CNS)
Carry the impulse from the Central Nervous System (CNS) to the effectors,
which may be muscles or glands
Each neurone consists of three key structures:
NEURAL
COMPONENT
Dendrite
Cell Body
Axon
FUNCTION
A group of fine branches that receive messages from receptors and other
neurones and convey nerve signals to the cell body
Contains a nucleus which supplies nutrients and energy for the activity of the
neurone
A long structure through which nerve impulses pass from the cell body. There
are axon branches at the end of the axon. It is covered by an insulating sheath
of myelin.
Nerve impulses travel along a neuron in ONE direction only – from dendrite to axon branch.
Neurons grouped together form a nerve.
SOME RECEPTORS FOUND IN
HUMANS
RECEPTOR
TYPE
Rods and cones
Auditory
Olfactory
Taste buds
Pain
Compression
Temperature
Posture
Blood pressure
Breathing
Water
Temperature
Sugar
Acidity
STIMULUS
WHERE FOUND
Light
Vibrations
Gases and vapours
Dissolved substances
Strong, potentially damaging stimuli
Touch, pressure
Heat loss of gain
Stretch
Tension
Position of bones
Force of blood
Oxygen
Carbon dioxide
Lung inflation
Lung deflation
Lung irritants
Change in water content
Core temperature
Glucose level in blood
Changes in pH
Eye
Ear
Nose
Tongue, epiglottis, pharynx
Throughout the body
Skin, muscles, joints, internal organs
Skin
Muscles
Tendons
Joints
Main blood vessels
Main artery
Hind brain
Lung
Lung
Trachea, bronchi
Hypothalamus
Hypothalamus
Hypothalamus
Hind part of brain