5 Sense Organs & their Functions
5 Sense Organs: Have you ever thought about how you feel about the seasonal changes in the environment? How do you see an object and its color in your surrounding? How do you hear the birds chirping? The answer to these questions is the presence of sense organs. Sense Organs are the unique organs of the human body that gather information and further respond to stimuli. The neural system is formed from highly specialized sensory neurons which gather raw information and translate them into signals which are taken up by the nervous system and respond immediately. Basically, we have five sense organs, namely, eyes, ears, nose, tongue, and skin. These specialized sensory organs are used to see, hear, smell, taste, and smell.
Sense Organs & Their Functions
The sensory organs detect all types of changes in the surroundings and send appropriate signals to the Central Nervous System, where all the inputs are processed and analyzed. Signals are then further sent to different parts/centers of the brain. So, in this article, we will discuss 5 sense organs in the human body which are essential and which respond to the external environment. The five sense organs are, namely:
1. Eyes- Visual Sensory Organs for Vision (Ophthalmoception)
The visual sensory organs of the human body are the eyes which are sensitive to light images. The color of our eyes depends on the amount of melanin in our bodies, and they aid in our sense of sight by detecting and focusing on light images. The iris is the visible colored portion of the eye that governs the pupil’s size and diameter. The amount of light entering the eyes is influenced by the size of the pupil. The aperture present around the iris is called the pupil.
The gelatinous fluid called vitreous humor which gives shape to the eyeball is located behind the lens of the eye. It also transfers light to the retina, which is the inner layer that has three neural cells, that is, ganglion cells, bipolar cells, and photoreceptor cells. These photoreceptors are of two types, Rods, and cones.
Cones: The daylight (photopic) vision and the color vision are functions of cones. Red, Green, and Blue are three different types of cones.
Rods: The twilight (scotopic) vision is the function of the rods. The rods contain a purplish-red protein called rhodopsin or visual purple, which contains a derivative of Vitamin A.
2. Ears- Auditory Sensory System for Hearing (Audioception)
The auditory sense organs ears play an important role in hearing or recognizing sounds. After the detection of sound waves or vibrations in the air, our auditory system helps us in hearing sounds. The ear is also an important sense organ for maintaining body equilibrium as the vestibular organ is present inside the ears.
Three parts of the ear are, namely-
Outer Ear: It consists of the visible portion known as the auricle or pinna, and a short external auditory canal (eardrum) enclosed by the tympanic membrane. The outer ear collects sound waves and makes these reach the tympanic membrane.
Middle Ear: It is a narrow air-filled cavity in the temporal bone and surrounded by three tiny bones that include a hammer (malleus), anvil (incus), and stirrup (stapes). Auditory ossicles are the name given to the combination of these bones.
Inner Ear: Two functional units of the inner ear are the vestibular apparatus having vestibule and semicircular canals, and the cochlea having sense organs of hearing.
3. Nose- Olfactory Sensory System for Smell (Olfacoception)
The nose is the olfactory organ of the human body. Its function is to perceive a variety of smells. The nose has olfactory cells(chemoreceptors), and as the air gets into the nose the receptors activate themselves and send signals to the brain which recognizes different smells. The hairs in the nose called cilia help to filter the foreign particles.
4. Tongue- Sensory Organs for taste (Gustaoception)
One of our sense organs is the tongue which helps in perceiving tastes and flavors due to the presence of taste buds. The little bumps on the top of the tongue called Papillae consist of these taste buds on the tongue and it helps in sensing different tastes. The nose and tongue, together are associated with, deciding flavors and work together to create a taste. Chemoreceptors are the receptors present in the taste buds which function similarly to that those present in the nasal cavity. The four essential taste buds on the tongue are sweet, bitter, sour, and salty.
5. Skin- Sensory Organs for touch(Tactiception)
The largest sense organ of our body is Skin and it relates to the sense of touch known as tactioception. It is a flexible outer covering of the body that comprises hair follicles, nerves, nails, and glands. The three major functions of Skin are protection, sensation, and regulation. It consists of sensory nerve structures or receptors that detect surface temperature, pain, physical touch, and chemical stimuli. The three layers of the skin include the following:
Epidermis: It is the outermost layer called keratinocytes that contain a protein called keratin. Melanocytes, Merkel cells, and Langerhans cells are also present in this layer. It is further divided into multiple layers.
Dermis: It is located beneath the epidermis and consists of papillae. It is responsible for making skin flexible and sturdy due to the presence of fat, collagen, and fibers. It plays an essential role in supplying blood for new cell formation via blood vessels.
Hypodermis: It is a subcutaneous layer made up of fat that provides energy and regulates temperature. It is highly beneficial for cushioning internal organs, bones, and muscles, and protecting these from injuries.
Other Sense Organs
Apart from the five sense organs mentioned above, there are other organs too that assist us in sensing things around us:
Vestibular System: The vestibular system serves as a sensory system for the body, delivering information about motions, head position, and spatial orientation to the brain. In addition, this system is involved in motor functions. It aids in maintaining body posture, body balance, head and body stabilization during movement, and even understanding our bodies’ orientation and posture with respect to the environment.
Proprioception system: The proprioception system aids the body in identifying the muscles, joints, and limbs located in 3D space, as well as the direction it is moving with respect to the body, whether it is conscious or unconscious.