The 5 organs of the senses are the eyes, skin, nose, ears and tongue. Its main functions have to do with the interaction between the human body and the stimuli of its surroundings.
The information provided by the senses in the form of nerve impulses allows the human being to move safely and independently. With the sense organs people can perceive light, sound, temperature, tastes and smells.
These stimuli become nerve impulses that are interpreted by the brain to generate a response. This process is possible thanks to the sensory receptors.
What are sensory receptors?
The sense organs have sensory receptors. These are structures with cells specialized in detecting specific types of variations in environmental conditions.
If such variations exceed a given value (threshold), the nerve impulse that travels through the neurons is generated.
According to the type of stimulus they perceive, the sensory receptors are classified into chemoreceptors, mechanoreceptors, thermoreceptors and photoreceptors.
Chemoreceptors
They allow to perceive chemical elements related to flavors and odors.
Mechanoreceptors
They are receptors that allow you to perceive textures, pressure, vibrations (such as sound waves), the feeling of balance and the contact or not of objects or other people.
Thermostats
These types of receptors intervene in the perception of temperatures.
Photoreceptors
With this type of receivers you can perceive the electromagnetic energy.
The 5 sense organs and their main functions
1- The skin: the sense of touch
The skin is the largest organ of the human body since it covers it completely. In the skin works the sense of touch. This sense allows to perceive qualities of external objects as texture, temperature, pain, pressure, among others.
In this way, the human being can calculate whether or not he touches certain objects, according to his ability to resist the sensations that such objects produce him. Internal nerve endings can also function as touch sensors.
The sexual organs and fingertips are the parts of the body with most nerve endings.
The skin has mecano and thermoreceptors in all its layers, which are dermis, epidermis and hypodermis. These receptors are presented in the form of Meissner's corpuscles (allow to perceive shapes, sizes and textures), of Pacini (help the organism to perceive the pressure and the weight of the objects), of Ruffini (they intervene in the perception of the heat) and of Krause (allow to perceive the cold).
In addition, the hairiness of the skin magnifies the sensitivity to the stimuli.
2- The eyes: the sense of sight
The eye is an organ that allows to capture the image of the external world. It is related to the sense of sight. This is the sense that allows people to see and recognize the shapes, colors and dimensions of the objects of the outside world.
It also allows the human to calculate the distances between himself and the objects around him.
To determine the main functions of the eye it is important to know its parts. The following are the characteristics:
Cornea
It is the transparent surface in which rays of light are refracted.
Iris
It is the part that controls the amount of light that crosses the eye pupil thanks to the ciliary muscles. In the iris is where the color of the eye is distinguished.
Pupil
It is the opening that is located in the center of the iris through which the light passes.
Crystalline
It serves as a regulator of the direction of light so that it reaches the retina correctly.
Retina
It is located at the back of the eye and converts the rays of light into electrical energy, so that it reaches the optic nerve.
Optic nerve
It connects the eye with the brain stem so that the electric energy reaches the occipital lobe, place of the brain in which the electric energy is transformed into an image
The operation of the eye is similar to that of a camera: light passes through the lens and goes to the retina, where the optic nerve leads to the brain and there reproduces the image.
When there is a lot of light, the iris shrinks by decreasing the amount of light that can pass through it. The eye perceives a spectrum of light ranging from red to violet.
3- The nose: the sense of smell
The nose is an organ located in the center face that relates to the sense of smell. Its inner part is in the sky of the mouth.
It has two pits that serve for the exit and entrance of the air of the breath. These fossae are separated by the septum, a structure formed by cartilage and bone that is covered with mucosas.
Inside the nose are the yellow pituitary, which has the olfactory receptors, and the red one, which contributes to the regulation of the temperature of the air that enters and leaves the lungs.
Also inside the nose there are villi called cilia, which help to filter the air of the impurities.
Also in this organ are the paranasal sinuses, which are four pairs of air-filled cavities that are located near the nostrils. Paranasal sinuses are classified as edmoidal, maxillary, frontal efenoidal.
With human scent can detect up to 10 thousand odors. Smells are vapors emanating from the various substances. It is also believed that in the nose there is a structure specialized in perceiving the pheromones related to the reproductive cycle of the human being.
With the smell is stimulated appetite and digestive secretions, thanks to chemoreceptors of the nostrils.
4- The language: the sense of taste
It is an organ located inside the mouth that has the function of hydrating both the mouth and food, and making the language possible. It is related to the sense of taste, which allows to identify substances soluble in saliva, to complement the function of smell.
The parts of the tongue are: upper and lower face, lingual edges, base and tip. It also has an osteofibrous skeleton and several muscles that enable its movement.
On the upper face are the taste buds with the chemoreceptors that allow to perceive the dissolved substances in the saliva.
This sense fulfills the function of allowing people to distinguish different flavors, being able to detect those that indicate that a food is in bad condition.
How does it work?
If a papilla receives a stimulus through one of the dissolved substances, it sends nerve impulses to the brain that are interpreted as flavors. The main flavors that recognize this sense are: sweet, bitter, acid and salty.
Each part of the tongue is specialized in capturing a flavor: the sweet is captured in the tip, the bitter near the base, the acid in the lingual edges and salty in the tip or the edges.
Women usually have better developed this sense than men.
5- The ear: sense of hearing
The ear is an organ that allows to perceive the sounds and their different qualities (volume, tone, timbre and origin). Its structure can be divided into internal, external and medium.
Sound waves enter the outer ear and travel through the ear canal to the eardrum, where they cause a vibration. This vibration moves three ossicles of the middle ear (hammer, anvil and stirrup).
The waves of ossicle movement reach the fluid in the inner ear where thousands of hair cells are found that transform the waves into electrical signals, which go to the brain thanks to the superior auditory nerves.
There, the brain combines the signals perceived from both ears to determine the distance and direction of the sound.
In the middle ear, the semicircular canals of the vestibular system are those involved in the balance of the human body and its sense of spatial orientation.
The ear can perceive frequencies between 16 (lowest) and 28 thousand (highest) cycles per second.
The type of receiver that the ears possess is called phonoreceptors, although it also has the mechanoreceptors that help to perceive the balance.
In fact, balance is a complex sensation in which the brain uses stimuli from the middle ear, eyes, proprioceptive sensors (located in skin and muscles), and the central nervous system.
Some authors include kinesthesia and synesthesia among the human senses.
References
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- El Popular newspaper (2017). The sense of touch: its function and parts. Recovered from: elpopular.pe
- Dosshop (2014). About the eye. Retrieved from: docshop.com
- Healthy children. Eyes, nose and throat. Retrieved from: healthychildren.org
- Hear it (s / f). The ear: a magnificent organ. Retrieved from: m.hear-it.org
- Zamora, Antonio (2017). Anatomy and structure of human sense organs. Retrieved from: scientificpsychic.com