The human body can be compared to a machine in terms of its functioning and organization, but the magnanimous human performs way better than that of a machine. A machine consists of several systems inside it, similarly, the human body has several systems inside it which are assigned for a specific task.

These systems coordinate with others and their joint activity is the reason for a human being at the top of the hierarchy. There are around 11 organ systems in the human body. This blog series is all about the organ systems in brief.

The blogs under these series are prepared to house important information regarding each system. So that one can recollect about a system within a few minutes of reading. This blog is about the integumentary system. This system comprises skin and body membranes. In short, it comprises the skin and its derivatives. The primary function of the skin is to protect and cover the body’s surfaces. The body membranes can be briefly categorized as epithelial and connective tissue. There are three subcategories within epithelial membranes namely cutaneous, serous and mucous.

The cutaneous membrane is mostly dry and contains keratin used for protection. The mucous membrane lines body cavities and is used for absorption and secretion. The serous membrane consists of special fluids and is present around the lungs and heart. The other important functions of the skin include the following.

•             Protection from UV, mechanical, electrical, chemical, and microbial damage

•             Prevents cell drying

•             Help in heat regulation

•             Excrete excess water as sweat

•             Synthesize vitamin D

The skin has three layers namely the epidermis, dermis, and hypodermis. The epidermis is the outer layer and is mostly keratinized. The layers in the epidermis namely

•             Stratum basale

•             Stratum spinosum

•             Stratum granulosum (above this layer all are dead cells)

•             Stratum lucidum

•             Stratum corneum

the layers of the epidermis

Melanin is one of the pigments which decide the color of the skin. It is produced in the stratum basale layer. The other pigments are carotene and hemoglobin. The dermis is the middle layer and is of two types, the papillary and reticular layer. The papillary layer has touch receptors and this contains the fingerprints which is a unique identity. The reticular layer has blood vessels, glands, and nerves. The hypodermis is the deep layer and mostly contains adipose tissue (fat tissue). The sebaceous gland and sweat glands, hair, and nails are skin appendages. The sebaceous gland produces oil-sebum which kills bacteria. There are two types of sweat glands namely eccrine and apocrine.

The hair consists of hard keratinized cells with melanocytes. There are some special structures called arrector pili, a smooth muscle that makes the hair stand straight known as goosebumps. The nails are scale-like modified, heavily keratinized structures present in the exteriors of the limbs. The stratum basale extends as a nail bed. Beyond it is the nail matrix which is essential for the nail to grow. If the nail matrix is torn off then the nail cannot grow. The skin and other components in the integumentary system provide an outer covering to the body. For many infections and damages, skin acts as the first line of defense. The study of the skin is called dermatology.


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