Nose is the sense organ for smelling. It is also the
important organ of respiratory system.
Our nose is
divided into two parts – external nose and internal nose. The external nose
consists of two openings called nostrils. The internal nose consists of a wide
cavity known as nasal cavity. The nasal cavity is divided into two cavities by
nasal septum. The nasal cavity consists of hairs which prevent the entry of
dust particles during respiration. The upper part (roof) of the nasal cavity
contains a special tissue known as olfactory mucosa. This mucosa consists of
cells called sensory cells. When a smell reaches to nasal cavity, it activates
the sensory cells of the olfactory epithelium. The sensory cells that send the
smell to the brain. Then we find out the smell.
Actually, the
nasal cavity is lined by mucous membrane. The olfactory epithelium covers the
small area of mucous membrane in human beings. In hence, they can detect very
faint smell also.
Defects of nose
Common cold causes the inflammation of the
nasal mucous membrane. It is due to the viral infection. The inflammation
hinders the smells from reaching the olfactory are and results in loss of sense
of smell. This is known as rhinitis.
Bleeding from
nose is common in children due to the minor trauma in nose. In such case, we
should keep our head little up and pinch the nose for some minutes.
Similarly,
when a person inhales a substance with a strong smell again and again, the
sense of smell for that substance decreases gradually and may disappear
altogether. This is due to the changes in sensory cells of nose and olfactory
region of the brain. This process is known as olfactory adaptation.
Care of nose
We should be careful for the
cleanliness and protection of our nose. We should take the following
precautions to protect our nose:
1.
We should blow and wash our nose to keep it clean.
2.
Fingers, pencils, matchsticks, etc should not be
inserted into the nostrils.
3.
If our nose is blocked, we can use nasal drops. But
excessive use of such drops is harmful. They should be used according to the
advice of doctor.
4.
We should inhale the strong smells or stenches.
They can damage our smelling capacity or make us sick.
5.
We should not take smell of flowers from a close
distance.
Tongue
The tongue is the sense organ of
taste. You can see a number of tiny knobs if you deserve the upper surface of
your tongue in a mirror. These tiny knobs present in the tongue are called
taste buds. There are about ten thousands taste buds in our tongue.
The surface
of the tongue is very sensitive in sensing sweet, salt, sour and bitter tastes.
There are different regions to notice
the different tastes in our tongue. The sweet taste is noticed by the tip of the
tongue whereas the bitter taste is noticed by the back part of the tongue. That
is why we know sweet taste earlier than the bitter one.
Sweet: The sweet taste is noticed by the tip of the
tongue.
Salty: The salty taste is noticed by the
region just inside (after) the tip.
Sour: The sour taste is noticed by the middle of the
tongue.
Bitter: The bitter taste is noticed by the
back part of the tongue.
Defects of tongue
The taste buds can be damaged by
very hot foods and drinks and the use of sharp things (while cleaning the
tongue). The tongue with damaged taste buds cannot detect the taste of food
properly. The sensory cells of the nose also help the taste buds while
determining the taste. Therefore, we cannot find the taste of food while we are
suffering from common cold.
Our tongue
is helpful not only to taste the food but also move food while chewing. It also
helps to produce different sounds while speaking, talking, singing, etc.
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