【The five senses】

The body of a human being is made up of many parts, ranging from the smallest cells to the largest organs that form various systems. Each of these systems has specific functions that contribute to the natural development of the organism.

Among those is the sensory systemresponsible for receiving information from outside that will be processed in the brain through the five senses: sight, smell, taste, hearing and touch. More information on this topic will be given below.

What are the five senses?

The senses of the human body are the means that a person has to receive information, from the inside or outside, to then be processed by the brain.

Human beings have five senses, which are: hearing, sight, smell, touch and taste.

The five senses are important to people because they give them the opportunity to explore the environment around them. Through them, you can look where you are passing, smell different fragrances, taste food, listen to the sound of the sea and the rain, touch and feel the textures and shapes of objects, among other things.

Sensory system and its receptors

He Sensory System It is composed of a set of highly specialized organs that allow the body to capture the different signals that come from the environment, to provide the nervous system with this information, which in turn will be responsible for processing it to react in favor of the body. healthy and coordinated.

Those responsible for collecting information from the environment that surrounds human beings are the sensory organs: eyes, ears, nose, tongue and skin. The tissues and cells of these organs receive untreated stimuli and transform them into signals available to the nervous system. Likewise, the nerves send these signals to the brain, which interprets them as sight (eyes), sound (hearing), smell (nose), taste (tongue and nose) and touch (skin).

Receiving organs of the five senses

For the sensitive or sensory system, the existence of receptor cells is essential, because they are the ones that translate the energy of the stimulus such as light, sound, pain, cold, heat, flavor, among others; into signals that are manageable and recognizable by the organism. Each of the five senses uses different organs, and in turn, different types of receptors.

The eye converts light into an image signal

The human eye is a photoreceptor organ that allows it to capture light rays from each object in the environment, and then convert them into electrical signals that generate a reaction. The information is collected in the retina and travels through the optic nerve, until it reaches the brain where it is processed to form meaningful images.

The images that are captured through the eyes provide human beings with information about the color, shape, distance, position and movements of objects. This allows them to know the environment that surrounds them and relate better to their peers.

How is the eye formed?

The organ of sight is made up of: the eyeball, the protective apparatus of the eye and the ocular movement apparatus. Furthermore, it is divided into three layers, internal, middle and external.

Knowing the parts of the eye is very important to understand how it works, and avoid injuries that affect the health of this essential organ for the visual system. Its parts are described below:

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Inner part

Retina: It is the layer located at the back of the eye that has tissue that is very sensitive to light. Optic nerve: group of nerve fibers that transmit light impulses from the retina to the brain. Macula: yellowish part of the retina, with the specific function of allowing the movements of images to be seen.

Middle Part

Lens of the eye: it is a transparent lens located behind the iris, which allows images to be focused from any distance. Iris: it is a muscle that regulates the amount of light that must pass through the pupils, and is also responsible for the color of the eyes. Vitreous gel: is the colorless gelatinous liquid found between the lens and the retina. This gel is responsible for the rigidity of the eye and for keeping the retina fixed. Pupil: it is the circular hole found in the center of the iris and that, depending on the amount of light perceived, dilates (becomes large) or contracts (becomes small). Ciliary body: covering of blood vessels and tissues located between the retina and the white part of the eye. It is what produces the aqueous humor, a colorless liquid that oxygenates the lens and the cornea, contributing to the retraction of light

External part

Eye orbit: it is the bony socket where the eye is located. This orbit has six extraocular muscles that give mobility to the eye. Sclera: is the white area of the eye of thick tissue that connects the six extraocular muscles. It covers the entire surface of the eyeball. Conjunctiva: is the transparent mucous membrane that covers the inner part of the eyelids and the sclera, to protect them. Cornea: transparent front layer of the eye that covers the iris and allows light to pass through.

The ear converts sound waves into acoustic signals

The ear is the organ responsible for the sense of hearing. Through it you can perceive the volume, tone and timbre of sounds, in addition to distinguishing where they come from. This organ receives the vibrations and then transmits them to the brain.

On the other hand, nerve terminals rest in the ear that collect information regarding the body’s movements, and contribute to its balance and stability. When a person has a small irritation or infection in the ear, they may have variations in the way they walk or stand.

Parts of the ear and their functions

The ear structure is divided into three parts: outer ear, middle ear and inner ear.

External ear: It is the pinna and the ear canal that ends in the eardrum that separates the outer ear from the middle ear. In this area the waves from the ear canal are concentrated and propagated to the eardrum. When sound waves collide with the eardrum, mechanical vibrations are created that reach the three small bones of the middle ear through the eardrum.
Middle ear: It is located inside the temporal bone of the skull. The middle ear is a system of cavities composed of: the tympanic cavity with three bones called the incus, hammer and stapes, responsible for transferring sound to the inner ear. The mammary cavity with the air cells of the mastoid process and the Eustachian tube.
Inner ear: It is formed by the labyrinth or snail, and the static auditory nerve. From this area of the ear, the vibrating signals from the middle ear are transformed into electrical impulses that travel through the cochlear nerve until they reach the brain, which interprets them as sound.

The skin sends tactile signals to the brain

The skin is the largest organ in the body, its main function is to cover all the internal organs and bones that make it up. Special receptor cells found within the skin panicles detect tactile sensations that transmit signals via peripheral nerves to the brain.

Layers of skin

It consists of three main layers, the outer epidermis, the middle dermis and the inner subcutaneous tissue.

Epidermis

The outermost part of the skin, the epidermis, is made up of several layers of epithelial cells, often called squamous epithelium. The thickness of the skin varies from place to place on the body. On the palms and soles of the feet there are thick layers since the wear is great. Otherwise, on the body the thickness is between approx. 0.05 and 0.1 mm.

Dermis

It is located under the epidermis, it is essentially composed of connective tissue and many elastic protein fibers, its thickness ranges between half and three millimeters thick, strong and elastic, and it protects what is underneath from blows and wounds. The dermis also has blood vessels and sensory cells. Blood vessels play an important role in regulating body temperature such as heat, cold or humidity. Likewise, it regulates blood flow when certain emotions occur in humans, such as blushing due to embarrassment.

Tissue subcutaneous It is the lower layer of the skin that is composed of fat cells and a small amount of connective tissue. Its thickness depends on the type of build the person has, it can be a few millimeters in thin individuals, up to more than 10 cm in others who are overweight. The fat that is deposited in this area, apart from molding the body, serves as an insulator against cold and heat, and also provides, along with the other layers of the skin, protection against shocks and blows.

Nose for smell

The organ of the body responsible for developing the sense of smell is the nose, however, it also provides its contributions to the sense of taste. Through the nasal passages, substances in a gaseous state can be inhaled that are dissolved in the thin liquid membrane that covers the sensory cells of the nasal mucosa.

There are a large number of receptors in the upper part of the nose, which detect odors using mucus-covered cilia, which are tiny villi that react to bad odors. The olfactory cortex that receives and processes these signals is located in the front part of the brain.

Parts of the nose and reception of odors:

The nose It is located in the center of the face, and is made up of two structures, the external and the internal. They are explained in the following lines.

External nasal structure

It corresponds to the parts of the nose that protrude from the face and can be seen. It is made up of the following parts:

Root: It is made up of a group of bones that connect the nose to the rest of the parts of the face.
Triangular cartilages: they form the internal valves which are responsible for controlling the passage of air and giving the nose a pyramid shape.
Alar cartilage: located at the tip of the nose and serves to create external valves that cover the nasal openings and filter the passage of air coming from the outside.

Internal nasal structure

It is the hidden part of the nose, which is under the nasal pyramid and cannot be seen with the naked eye. It is made up of these structures:

Nasal Cavity: It is located on the nasal pyramid, inside the nose and has a layer or mucous membrane that allows the humidity of this organ to be controlled.
Nasal vestibule: It is located at the back of the nostrils, and is responsible for preventing the absorption of dust or foreign particles that may be present in the air that is going to be inhaled.
Partition: It is made up of bones and cartilage, it divides the…