Sense Organs (Class VIII)

It is the outermost layer of the eye.

Conjunctiva covers and protects the cornea.

Cornea is the transparent scleroid, which is present in the anterior of the eye.

In bright light, the pupil of the eye becomes smaller to prevent too much light from entering the eye.

Lacrimal gland produces tears that wash away the foreign materials and irritants, and prevents injury.

Yellow spot is the most sensitive part of retina.

Vitreous humour is present in the posterior chamber.

Lens is present behind the iris and pupil. It is capable of exerting accommodation power.

The ability of the eye to bring objects lying at various distances to focus on the retina is called accommodation.

It is the shortest bone of our body and is present in the middle ear.

There are 3 small bones present in the middle ear, namely malleus, incus and stapes.

Sebum protects the skin from bacterial and fungal infections.

Cats have amazing hearing ability. A cat's ear has 30 muscles that control the outer ear (by comparison, human ears only have six muscles). These muscles rotate 180^o, so the cat can hear in all directions without moving its head.

Sweat glands keep the body cool by giving off moisture in the form of sweat.

Olfactory nerve is present in the nose. It sends the impulses to the brain.

Skin produces the sensation of touch, pressure, cold, heat and pain.

Skin is the largest organ of the body. It covers the whole of the human body.

Anterior chamber is present between the cornea and the lens.

In presbyopia, there is decrease in the accommodation power of the eye.

Choroid prevents the reflection of light rays within the eyeball and nourishes the retina.

Pinna and ear canal belong to the outer ear.

It collects sound waves and focuses them onto the eardrum.

Melanin determines the colour of the skin.

Cochlea contains receptors to detect sound vibrations and trigger impulses.