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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
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
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
The nostrils lead into the nasal cavities which are lined by the olfactory epithelium. The sense organs of smell are situated in the epithelial lining of the upper part of the nasal cavity.
When we smell a strong odour, at first it reacts with the chemoreceptors of our nose and thus, we can identify it but as it felt for long time then the chemoreceptors become accustomed to it and thus, we cannot further identify it.
Flavor is the combination of taste and smell in which both senses i.e. gustatory and olfactory receptors are simulated at the same time. Therefore, we cannot receive the proper flavor of food when we are suffering from cold.
The receptors of salty taste lie at the tip of the tongue whereas those of bitter taste lie at back of the tongue. So, salty taste is felt faster than bitter taste.
When we are suffering from cold, the epithelium of our nose is swollen due to which the chemicals coming from the odorous substances could not reach to the olfactory nerves. So, they could not be identified.
Mainly, tastes are divided into 4 parts, which are listed below.
The tongue is cared by the following ways:
a) We should regularly clean our tongue at the time of brushing our teeth.
b) Very hot and very cold food destroys the taste buds and we may not further recognize the taste. So, we should not have such foods as far as possible.
The skin is cared by the following ways:
a) We must keep our skin clean regularly cleaning and bathing.
b) We should wear comfortable and sweat absorbing clothes.
c) In case of skin allergy or infection, we should consult with doctors.
d) We should not expose our skin to the direct UV-rays of the sun.
e) The wound and cuts should be treated with antiseptic liquids prevent it from infection.
The nose is cared by the following ways:
a) We should cover our nose in pollution zones. Using masks in such regions is very good for it.
b) We should not have the habits of putting finger in nose.
c) In the case of bleeding from nose we should rest our head by keeping the nose up.
d) In the case of infection in nose we should consult a doctor.
The outermost protective layer of the skin is called ______.
The nerve ending of the dermis are also called ______.
The inner lining of the nose surface is made up of ______.