What is our skin made up of?

Question

Again, it is a basic question. What is our skin made up of? is it made up of many cells arranged in a systematic way or is it just like any layer say of a book?? what is the difference? where is the living and dead thing coming into picture? is it the fact that skin can self-heal makes it living and in turn made up of cells??

Answer 1

Skin is made up of many layers of cells. We can divide these layers into 2 broad categories, Epidermis and Dermis. The epidermis is the superficial layer of skin(the layer we can touch and feel). The Epidermis is further divided into layers depending on the cell types present.

An easy way to remember the layers is a great mnemonic; Californians Like Good String Bikinis

From Superficial to Deepest, Corneum, lucidum, Granulosum, Spinosum, Basale

All the layers present have their own special functions such as, the most superficial layer(Corneum) has no nucleus and mainly consists of cells that progressively move up from the deepest layer(basale). The Deepest layer(basale) contains the stem cells(the cells that make all the other cells of the epidermis) from which the cells move progressively to the superficial most layer where they get their nucleus removed and eventually are shed from the skin as dead skin.

The reason for the cells in the corneum to not have nuclei and specialized keratin is to prevent loss of fluids(as the skin has a large surface area and can participate in heating/cooling. Another reason for this to prevent infection by forming a complex interconnection between these cells and acting as a barrier.