(a) What is a receptor?
(b) Describe the general features common to all receptors.
(c)(i) Make a labelled diagram 8cm – 10cm long, to show the outer and middle ear only of human.
(ii) List three ways of caring for the ear.
Explanation
(a) A receptor; is a sensory cell which receives stimuli, initiates and transmits an impulse through neurons to the brain, spinal cord or the central nervous system.
(b) General features common to all receptors: Generally, receptors consist of a group of sensory cells with their free surfaces bearing, short hair-like processes otherwise called dendrites. Around their basal portions are nerve fibres which lead to the spinal or cranial nerves and the central nervous system.
(c) Diagram showing the outer/external and middle ear of human.
(ii) How to care for the ear:
(i) avoid inserting sharp objects into the ear
(ii) clean regularly with cotton buds
(iii) report any ear discharge or problem to the medical doctor
(iv) avoid places of loud noise
(v) avoid misuse of ear-phones
(vi) avoid introducing hot liquid into the ear
(vii) treat measles and meningitis instantly to prevent deafness
(viii) avoid using quinine carelessly