The human body has 5 sense organs, that are essential for life. These include
- Eyes
- Ears
- Nose
- Tongue
- Skin.
They are special because they provide up to 80% of the sensory stimuli we perceive.
These organs enhance convenience and protect life.
Damage to these organs will lead to disability for life.
Sense Organs in detail
Eyes
These are the organs of sight, and a pair exists. They are prominent sense organs and are connected to the brain by the optic nerve (3rd cranial nerve).
👉 Read our detailed article on the structure and function of the eye.
Features and functions
- Eyes are located in the orbital cavity of the skull near the forehead.
- They are spherical in shape, with a diameter of 2.5 cm.
- The retina is the critical part of the eye, containing sensory receptors.
- The photons from the light falling on the retina are converted into an electrical impulse passed on to the optic nerve for processing.
- Though two eyes are separate, they are coordinated in such a way that they function as a pair.
- The eyes are always kept moist by lacrimal secretions to keep them clean.
- Even if one eye is restricted, vision can be impaired to some extent.
- They are so delicate, and if they are damaged, it could be hard to restore their function.
- Loss of vision greatly affects one’s life, as one cannot see and needs daily assistance.
Ears
The ear is the sense organ responsible for hearing and balance.
A pair of ears is present, with one on each side of the head.
👉 Read our detailed article on Anatomy of the Ear.
They are supplied by the 8th cranial nerve, which is called the auditory nerve.
Features and functions
- The ear has distinct parts, including the tympanic membrane, ear ossicles, vestibule, and cochlear apparatus.
- Sound waves (mechanical energy) are converted into electrical energy and transmitted to the auditory nerve for perception.
- This process is helped by the tympanic membrane, ear ossicles, and the cochlear apparatus.
- If there is a problem with the ear, it affects balance more than hearing.
Nose olfactory apparatus
This is the organ of smell, and is also part of the respiratory system.
- It is the opening through which air enters and also leaves the lungs.
- But in the roof of the nose, there are olfactory nerves that help in the perception of the sense of smell.
- The chemicals in the air (volatile form) are captured by the olfactory receptors.
- This chemical signal is processed into a sense of smell upon reaching the brain’s olfactory center.
- Since the olfactory receptors are present on the roof of the nose, sniffing helps to concentrate the sense of smell.
- This sense of smell helps in appetite and also protects from consuming harmful foods.
Tongue
The tongue is the organ of the sense of taste.
It is a solid organ with a mass of tissue. But, yet it is quite flexible in its movements.
- There are many taste buds on the tongue which have chemoreceptors.
- These chemoreceptors sense the taste of chemicals in the liquid form and pass impulse on to the taste center in the brain.
Basically, the tongue can recognize 4 major tastes like the sweet, salt, bitter, and sour.
However, it can also recognize many other tastes.
Functions of tongue:
- Tongue helps in speech
- In sense of taste
- In chewing the food
Skin
Skin is the organ of sense of touch and it covers the whole body.
- It helps perceive the senses like heat, cold, hardness, smoothness, roughness, pain, pressure, etc.
- This sense of touch is essential to avoid injury to the body as seen in reflex
- It also helps excrete waste from the body.
Sense Organs Quiz
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