The Senses

The Senses

By Naomi Keddy

The human body contains five known senses which are taste, touch, smell, hearing and sight.

Taste:

The tongue is the organ of taste. The taste buds taste the following:

• sweet
• Sour
• Salt
• Bitter

The nose is the organ of smell. Olfactory neurons in the nose detect many smells.

The Eye:

The Eye is the organ of sight and it maintains many parts of the eye and functions are as follows:

Eyelids: can cover and protect the eyes. 

Conjunctiva: thin transparent lining protecting the cornea

Cornea: front transparent part of the sclera. It focuses light rays on the retina.

Sclera: is a though, white coat that holds the eye in place.

Choroid: contains blood vessels supplying food and oxygen to the cells of the eye. 

Retina: the innermost layer that contains the receptor cells (rods and cone shape).

The fovea: is where our best vision is (mainly cone shape)

Iris: contains blood vessels and melanin [giving us our eye colour], and controls the amount of light entering the eye 

Pupil: is the black circle at the front of the eye. It lets light into the eye.

Cillary muscles: change the shape of the lens to focus the light on the retina.

Aqueous and vitreous humours: keeps the eye in shape.

Optic nerve: carries impulses to the brain.

Lens: focuses light on retina.

The Ear:

The Ear is the organ of hearing and balance. The functions of the parts of the ear are as follows:

• Pinna: outer visible ear, funnels sound into the ear canal
• Auditory canal: tube leading to the ear drum. It has hairs and wax glands to trap dirt and germs
• Eardrum: membrane of skin that vibrates when sound waves hit it and carries vibrations to the middle ear
• Ossicles: (the hammer, anvil, stirrup) amplify the vibrations and pass them on the cochlea.
• Cochlea: is responsible for hearing. It contains nerves that convert sound vibrations into electrical impulses.
• Semi-circular canals: help us keep our balance and posture.
• Eustachian tube: is not part of the ear, it connects the middle ear the pharynx and equalises pressure.
• Organ of corti: in the cochlea which contains receptor cells that allow hearing.

Hearing disorder:

Glue Ear is:

• A hearing disorder
• Caused by too much sticky fluid in middle ear
• Corrected by decongestants and grommets.