The skin is made of layers of cells and tissues, which are held to underlying structures by connective tissue. There are Mainly 3 layers of skin and each of these layers have their own functions.
Do you know, the skin is a complex and largest organ an average square inch of skin contains 650 sweat glands, 20 blood vessels, and more than 1,000 nerves.
Despite being just a few millimeters thick, the skin makes up around one-seventh of our body weight.
Skin plays a vital role as a protective barrier, so it’s made to be tough and stretchy. The skin helps us maintain the right internal temperature and allows us to sense the world.
What are the functions of the 3 layers of skin?
Functions of the 3 Layers of Skin
There are 3 main layers of the skin. —
Basic diagram of 3 Layers of Skin
The epidermis is the outermost top layer of the Skin. It is a waterproof barrier that gives skin its tone.
Dead cells are shed continuously from the epidermis layer as new ones take their place.
We shed around 500 million skin cells every day. In fact, the outermost parts of the epidermis consist of 25–30 layers of dead skin cells.
New cells are made in the lower layers of the epidermis. In around 4 weeks, they make their way to the surface, become hard, and replace the dead skin cells as they are shed.
Keratinocytes are the most common cell type within the epidermis; their job is to act as a barrier against bacteria, parasites, fungi, viruses, heat, UV radiations.
The epidermis does not contain blood vessels.
Cells called melanocytes are melanin-producing neural crest-derived cells that are located in this layer of the skin’s epidermis. Melanin is produced and this melanin pigment gives color to the skin.
Between the epidermis and the dermis layer of skin, there is a thin sheet of fibers called the basement membrane.
Dermis layer makes sweat and oil, provide sensations and blood to the skin, grows hair.
The dermis is mostly connective tissue, and it protects the body from stress and strain. Also, it gives the skin strength and elasticity.
Receptors that detect pressure (mechanoreceptors), pain (nociceptors), and heat (thermoreceptors) are based in the dermis.
The dermis contains hair follicles, blood vessels, and lymphatic vessels. It is also home to a number of glands, including sweat glands and sebaceous glands. Sweat glands make sweat, which goes through little tubes and comes out of holes called pores.
The sebaceous gland produces sebum, an oil that lubricates. This oil keeps your skin soft, smooth and glowing. Nerve endings in the dermis help you feel things. They send signals to your brain, so you know how something feels if it hurts (meaning you should stop touching it), is itchy or feels nice when you touch it.
The dermis also has two sublayers
The papillary dermis region contains vascular networks that have two important functions. The first being to support the avascular epidermis with vital nutrients and secondly to provide a network for thermoregulation.
The reticular dermis is the lower layer of the dermis and it is found under the papillary dermis. It is composed of dense irregular connective tissue featuring densely packed collagen fibers. It is the primary location of dermal elastic fibers.
The reticular dermis is usually much thicker than the overlying papillary dermis. Protein fibers in the reticular dermis give skin its strength and elasticity.
This Layer Of Skin Attaches dermis to the body, Controls body temperature, and stores fat.
The hypodermis or subcutis is another name for subcutaneous tissue. It is not technically part of the skin but helps attach the skin to underlying bone and muscle. Subcutaneous tissue also provides the skin with nerves and blood supply.
The subcutaneous tissue is mostly made of fat, connective tissue, collagen and elastin (an elastic protein that helps tissues return to their normal shape after stretching). The high levels of fat help insulate the body and prevent us from losing our body heat.
The fat layer also acts as protection for our bones and muscles. Blood vessels and nerve cells that start in the dermis get bigger and go to the rest of your body from here. The subcutaneous fat is the layer that helps keep your body from getting too warm or too cold. This fat pads your muscles and bones and protects them from bumps and falls.