Common Skin Disorder (Acne)

Acne

a common skin disorder that often occurs during adolescence. It is caused by the overproduction of cells and sebum that combined to form a plug that blocks the hair follicles. Over time, the trapped sebum allows bacteria to grow in the follicle and eventually forms acne.

Process of the Production of Acne:

Excess cells+sebum (an oily substance secreted by  sebaceous glands)àformation of a plug àinfection with bacteriaà eruption of acne

In short, acne is caused by the blockage of hair follicles.

The Evolution of Human Skin

Past History

Our skin has not always been the same. Over the centuries, human skin has been gradually evolving in order to cope with the living environment. Paleontologists, people who study the history of life, have acknowledged the idea that human ancestors once possessed bodies covered in dense hair and rough skin. These two traits were important for human ancestors because they needed rough and hairy skin to protect them from the harsh winter, since the houses that they lived in back then were poor insulators against the bitter winter. As a result, the most obvious evolutionary adaptation is the roughness and the hairiness of skin.

 
 

Basic Concepts of the Human Skin

What is Human Skin?

Human skin is the largest organ that acts as the primary defense line against disease and injury. It protects the body from excessive water loss and receives information from the environment through nerves that respond to pressure, pain, heat or cold.

The Layers of Skin

        Human skin is composed of three distinct layers that function differently. They are "epidermis," "dermis," and "hypodermis (subcutaneous tissue)." 

A cross-section of human skin

    Epidermis- the topmost layer of skin that consists of mainly dead and dying cells. It is also the scientific term for the word "skin." 

    Dermis- the second and the middle layer of skin that is supplied with blood vessels, nerves, hair roots and sweat glands. It is where new cells are born.

    Hypodermis (aka. subcutaneous tissue)- the third and the innermost layer of human skin.Contains larger blood vessels, nerves and clumps of fat-filled cells that cushions the skin.