The Sense Organ of Taste, Touch and Smell

The sense organ of taste: the tongue

The tongue is a muscular organ in the mouth cavity. The tongue is surrounded by endoderm. The endoderm has five vertical folds, which contain a number of papillae. The papillae consist of millions of test buds which are supplied with nerves. When wet food passes by these taste buds, the nerve fibres carry the sensations of the taste to the brain. There are different types of receptors on the tongue. Sweet receptors are located at the tip of the tongue, salt receptors at the tip and anterior sides of the tongue,sour taste receptors at the middle sides of the tongue and receptors of a bitter taste in the back of the tongue.

Care and protection of the tongue

• Very hot and very cold foods may harm our taste buds.
• We should consult a doctor in the case of infection on the tongue.
• We should wash the tongue cleaner to clean our tongue after brushing.

The sense organ of touch: the skin

Skin is the outermost covering of the body which is protective and sensitive in function. It helps to balance the internal environment of the body. The skin consists of three layers: Epidermis, Dermis, and Sub-cutaneous.

Epidermis is the outer most protective layer with hairs, nails, pores, etc. The dermis contains blood vessels, nerve endings, glands, etc. Nerve endings are also called touch corpuscles or touch receptors which are found especially numerous on the fingertips, lips, etc. They are sensitive to cold, hot, pain, pressure and touch. Dermis is followed by Sub-cutaneous.

Care and protection of skin

• We should bath daily as far as possible.
• We should wear sweet absorbing cloths.
• We should protect our skin from direct sun heat.
• We should consult a doctor in case of infection in the skin.

The sense organ of smell: the nose

The nasal cavity is divided into two nostrils by a vertical septum. The inner part of the nose is lined with epithelium. The roof of the nasal cavity is concerned with the senseof smell and remaining part concerned with breathing. The uppermost is covered with epithelium which is connected to the nerve fibres of the cranial called olfactory nerve.
When we breathe, the microscopic particles coming from the odorous substances are carried into our nose which comes in contact with olfactory nerves. Here, some chemical reaction takes places and stimulates the nerve ending forming sensory impulses for sensation. These impulses are carried by the cranial nerve into the brain.

When a person suffers from cold, the epithelium is swollen and the particles of odorous substances cannot reach the olfactory nerves and therefore, he/she does not get the sense of smell.

Care and protection of nose

• We should not have the habit of picking the nose.
• We should cover the nose in polluted zones.
• In a case of infection in the nose, we should consult a doctor.