Epidermis

The skin has three main layers Epidermis, Dermis, and Hypodermis. Epidermis is the upper layer of the skin. It protects the body from heat, Pathogens, and the outside world’s unwanted things of the body. It regulates body temperature and amount of the water to be released from the body.

Features of Epidermis:

• A most superficial and thin layer of skin.
• It contains cholesterol.
• Melanocytes are present in the epidermis and determine the color of the skin.
• Two types of pigments are secreted by the skin melanocytes.

1. Eumelanin: It provides pigmentation to skin, hair, and eyes.
2. Pheomelanin: It makes pink or red pigmentation.                                            

Layers of Epidermis:

Epidermis contains five layers including the stratum basal (Deepest Portion of the epidermis), Stratum spinosum, Stratum granulosum, Stratum lucidum, and stratum corneum (Superficial portion of the epidermis).

• Stratum Basal: It is the deepest layer of the epidermis. It separates the epidermis from the basal membrane and attaches the basal membrane by hemidesmosome. This layer contains melanocytes and also continuously produces keratinocytes. This layer consists of cuboidal to columnar active stem cells.
• Stratum Spinosum: It contains irregular cell structures sometimes also called prickled cells. It is always found in the 8-10 layer. It contacts neighboring cells by desmosomes. Dendritic cells can be found in this layer.
• Stratum Granulosum: It is of diamond-shaped cells. It contains lamellar granules. Keratohyalin granules found in this layer it is a keratine precursor that eventually aggregates, crosstalk, and forms bundles. Diamond shape cell usually contains 3-5 layers of cells.
• Stratum Lucidum: Here 2-3 layers of skin are found where ever thickness is needed in the skin of the body. It transforms the product of keratohyalin by eleidin.
• Stratum Corneum: It is the uppermost layer of skin. It is made of keratin and the dead layer of the horn scalp. Keratinocytes present in it that is our first immune defense. 

Functions of Epidermis:

The function of the epidermis includes touch, Sensation, and Protection against Pathogens. 

• It acts as the first line of defense.
• It produces fatty acids so that microbes can not survive on the skin.
• It contains melatonin that reaction gives skin color.
• It releases glycogen and a hydration reaction making skin moist and protecting the body.
• Contain always active stem cells that replace old cells with new cells.

Skin is the outermost layer of the body and serves as the first line of defense from invading foreign particles. It secrets acids and salt in liquid form. Epidermis is the outermost layer present on the body and the Dermis is the dense irregular connective tissue present beneath the epidermis. Dermis contains body fluids and vein that leads to blood circulation.