THE STRUCTURE AND FUNCTION OF THE SKIN
The structure and function of the skin– The upper body cover is called the skin. Did you know that the skin is the largest organ in the human body. The body’s integument system, that is, the skin, is an important system because many lifesaving functions are performed by it. The skin is a boundary barrier between the body and the environment, through which all things are regulated. In this way, the skin acts as an anti-mural between the tissues of the body and the external environment; It acts as the senses for environmental protection and plays an important role in controlling the temperature of the body. our skin performs three main functions are sensation, protection, and regulation of temperature. To understand the useful body functions performed by the skin, the study of the structure of the skin is mandatory. According to the structure, the skin is mainly made up of two layers.
EPIDERMIS [outer most layer]
DERMIS [beneath of epidermis]
HYPODERMIS
These two layers are subdivided into multiple layers. It remains separate from each other on both sides with a fine, shapeless, basement membrane. There is a layer of loose connective tissue under the dermis, which is called the hypodermis. The epidermis is made up of the ectoderm and the dermis and the tissue beneath it are formed from the mesoderm.
EPIDERMIS
The structure and function of the skin– It is the outer layer of the skin. This is the superficial layer of skin, which consists of several layers of stratified epithelium. It is of different thickness in different parts of the body, such as is very thick and hard on the palms and soles, etc., and it is very thin and soft on the inner surface of the torso, eyelids, lips, and extremities. There is no nerve ending and blood vessels present in the external skin, but mostly so thin, that even a slight cut reaches the dermis and blood starts flowing. The outer skin is transparent and water-impermeable. Water, bacteria, and some chemical substances cannot penetrate through it, but oily substances are absorbed by it freely.
In the outer skin, the composition, arrangement, shape, and size of the cells are of different types and on the basis of this, there are four different layers. Their position from outside to inside is in the following order.
- STRATUM CORNEUM
- STRATUM LUCIDIUM
- STRATUM GRANULOSUM
- STRATUM GERMINATIVUM
STATUM CORNEUM
This layer is the outermost layer in the body. The cells in this layer are very hard and rigid and are also called horny layers. The cells present in it are flat, thin, and nucleus-free, in which the protein of the protoplasm takes place in a fibroid called keratin, which is waterproof. These cells undergo lifelong destruction due to natural destruction and friction.
STRATUM LUCIDUM
This layer is extremely thin and somewhat transparent. Its cells are flat, clean, and transparent without a nucleus. Both the outer lines and the boundary of the cells present in this layer are so vague, causing the entire layer to appear differential and homogeneous.
STRATUM GRANULOSUM
This layer is made up of large and flat polyhedral cells of clear size, in which the nucleus and corpuscles are clearly visible.
STRATUM GERMINATIVUM
This layer is quite wide and thick and is made up of big cells. The cells in this layer are columnar in shape and contain a nucleus. From these, new cells are produced, which gradually move towards the surface and change in them. This layer consists of two types of layers called stratum spinosum and stratum basale.
- STRATUM SPINOSUM- The stratum spinosum layer consists of cells of different sizes, each consisting of small protrusions like thorns, which are connected to each other by microtubules; these cells are called prickle cells.
- STRATUM BASALLY- This layer is a single layer made up of dense cuboids cells on the basement membrane. From these cells, continuous new brachial cells are generated by cell division. Pigment cells [melanocytes] are found in this layer, from which the pigment called MELANIN originates. Skin color depends on the result of these pigment cells. The lower the stratum basale, the more fair the skin is, and the higher their volume is, the darker the color of the skin. The function of pigment is to absorb the rays of the sun and as a result of this action; the skin is protected from the strong rays of the sun.
DERMIS
The structure and function of the skin- The dermis is called real skin. It is formed in collagenous from elastic connective tissues, reticular and elastic fibers. Collagenous fibers, which are made of the protein collagen, are very thick, which makes the dermis hard and has elasticity due to elastic fibers. It usually contains fibroblasts, fat cells, and macrophages, which digest the external substances. It contains blood vessels, sweat glands, lymph vessels, hair follicles nerve endings, adipose tissue, and small amounts of involuntary muscle fibers.
DIFFERENT PARTS OF DERMIS
The upper part of the dermis is called the external papillary level and the lower reticular level. The two levels cannot be clearly separated. The lowest layer of the dermis is of different thicknesses from different individuals, it is called the subcutaneous layer. In this only connective tissues remain, but there is less or more amount of fat. The dermis layer remains thick in some parts of the body and thin in some parts. This removes the inequality of the surface of the body and fills the depths. The bones close to the skin provide padded support from them.
THE SKIN HAS THE FOLLOWING FUNCTIONS IN THE BODY
Protective in nature
The skin is the protective outer covering of the body, which acts as a defense wall for the soft organs, muscles, blood vessels, etc. of the body. It protects the body organs from external injury. It acts as an inhibitor against harmful microbial and external substances entering the body. The skin is a WATERPROOF, so it does not allow the external fluids to enter and prevents the fluids of the tissues from coming out. Skin also plays an active role in protecting the body from diseases.
Absorption of substance
The skin has the ability to absorb oily substances. It spontaneously exploits lipids and vitamins.
Regulation of temperature
Although the skin is fully water-proof, its outer surface remains moist with fluid secreted by the white tubes of the white glands. Sweat is emitted from the superficial pores of these micro drains and due to the influence of the environment; it continuously evaporates, thereby maintaining a cool effect in the body. In humid weather, the body is not able to cool down easily because the air outside is often saturated with water and sweat persists on the skin instead of evaporation. In cold weather, the skin acts as an insulator, due to which the heat remains in the body and the body remains warm. Additionally, a dense network of blood vessels exists in the dermis. In hot weather, the vessels dilate and the heat radiation from the blood increases, thus the heat of the body decreases.
Emission of waste
The skin excretes some amount of wastes such as urea etc. through sweat. The skin also removes about 1 gram of wasted nitrogen out of the body at the rate of every hour.
A general sensation of body surface
The skin receives sensations of touch, pressure, pain, cold, and heat and sends them to the brain. These functions are performed by the nerve endings of the nerve fibers present in the skin. Tactile corpuscles made of nerve fibers only act as neoplasms, because the root of the hair also contains the excess of nerve fibers, so the hair also helps in the sensation of the skin.
Secretion
The sebum is produced from the existing dermal glands in the skin. Fatty acid, cholesterol, and ergosterol are mainly present in this secretion. This lubricates the skin so that the skin remains smooth. In winter, the skin becomes dry and flaky when its secretion decreases.
Storage of substance
The dermis and subcutaneous tissues store fat, water, salts and glucose, and other substances.
Maintaining Water balance: The formation and evaporation of sweat is an important element in maintaining water balance within the body.
Maintaining Acid-base balance
The reaction of sweat is acidic, so along with it, unnecessary acids are expelled from the body in sufficient quantity. In the state of acidosis, sweating becomes more acidic and increases the expulsion of acid in the body. In this way, the skin helps to maintain the identical process within the body.
Synthesis in the body
The ergosterol is present in the sebum produced in the dermal glands of the skin, which causes the production of vitamin D by the actions of the sun’s ultraviolet rays, which perform many functions of the body and are very important for healthy functioning.
The structure and function of the skin
READ MORE- chemical composition of the body
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