SENSORY RECEPTORS
The principle function of the special sensory receptors is to detect environmental stimuli and transduce their energy into electrical impulses. These are then conveyed along sensory neurons to the central nervous system, where they are integrated and processed and a response is produced.
On the basis of stimuli receptors are categorised as:
(I) Mechanoreceptors : Respond to mechanical forces.
such as touch, pressure, vibration, etc.
(ii) Thermoreceptors Respond to temperature changes. Include free nerve endings and Krause's
end bulbs.
(iii) Chemoreceptors : Respond to chemicals. Include
olfactory cells in the nasal mucosa and taste buds.
(iv) Nociceptors: Respond to painful stimuli which may
be damaging to tissues. Include free nerve endings
(v) Photoreceptors : Respond to light energy. Include
cones and rods in the retina.
The most complex sensory receptors, are called sensory
organs. They consist of numerous sense cells, sensory neurons and associated accessory structures, e.g, eye and ear have a level of complexity of sense organs.
