Sense organs are made up of sensory cells that allow us to respond to physical stimulus. The human body consists of five sense organs which are the eyes (for vision), nose (for smell), ears (for listening), tongue (for tasting), and skin (for touch).
Sense organs have cells present inside them that detect sensations which are sent to our brain via nerves. Stimuli in the environment generate sensations and lead to activation of the receptor cells in the peripheral nervous system.
There are two different categories of receptors in our body, which are the general and special receptors. General receptors are present throughout our body whereas special receptors are confined to specific places. Let us now study these five sense organs and their functions in detail.
Five Sense Organs and their Functions
As stated above, the eyes, nose, ears, tongue, and skin have different functions; you can understand the structure and function of each sense organ in detail here.
Eyes are sense organs that provide us with the ability to see things around us. It allows us to see objects by collecting light and converting it into electro-chemical impulses in neurons. In humans, the main components of eyes are cornea, iris, pupil, eye-lens, ciliary muscles, and retina.
Our eye is roughly spherical in shape. Let us discuss the functions of each component in brief.
Component of Eye
It is the outer coat of the eye that performs the function of protection.
Iris is present behind the cornea. Its function is to regulate the amount of light entering the eye by adjusting the size of the pupil.
The size of pupil contracts when the amount of light around is high while its size grows bigger when the amount of light around is less.
The eye lens is located behind the pupil and made up of transparent material. It focusses the image of an object on the retina.
The ciliary muscles are responsible for adjusting the focal length of the eye-lens in accordance with the distance of the object from the eye.
Retina helps to form an image in the eye. It is attached to the optic nerves, which carries the image in the form of signals to the brain.
The nose is the most protruding part of the face that helps us to smell and breathe. As the nose is the first part of the respiratory system, air enters our body through nostrils. As soon as it goes past the olfactory system, the brain recognizes and identifies smells.
The structure of our nose is determined by the presence of nasal bones and the nasal cartilages. This framework is well supported by different types of soft tissues such as skin, epithelia, muscles, nerves, blood vessels, and mucous membrane.
Ears are sense organs that allow us to hear the sound around us caused by sound waves. When any external object generates a noise, sound waves get converted into the electrical impulse. The compressed is converted into electrical signals that are carried to the brain via auditory nerves.
The human ear is made up of three parts which are as follows.
Parts of Ear
Components and Structure
It comprises an ear canal, eardrum and a pinna.
It is made up of three delicate bones which are- anvil, hammer, and stirrup. These three bones are interlinked with each other. The lower part of the ear is characterized by the presence of the Eustachian tube.
The path of the middle ear leads to a coiled tube called the cochlea, which is composed of nerve cells that are sensitive to the sound. Auditory nerves present inside the ear carries the sound signals to the brain.
The tongue is not only a sensory organ but also an important part of the digestive system. With the help of our tongue, we can perceive tastes and flavours. The upper surface of the tongue contains taste buds that are found between papillae.
Another important role of the tongue is that it helps in the mastication of food and its swallowing. Due to the presence of salivary glands in the mouth, the tongue is kept moist by saliva.
Skin is the fifth sense organ of our body that perceives the feeling of being touched. It is the largest organ of the body; it protects our organs from microorganisms and also helps control body temperature.
The skin is made up of three layers, the epidermis, the dermis, and the hypodermis. The epidermis protects us from environmental elements. The dermis, beneath the epidermis, comprises strong connective tissue, sweat glands, and hair follicles. The innermost layer, the hypodermis is made of fat and connective tissue.
This was all about the five sense organs and their functions. You must know the functionalities and structure of each organ as it is a key topic from the perspective of competitive exams. You can expect a few questions related to five sense organs in the general awareness section of any competitive exam.
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