Integumentary System - Anatomy and PhysiologyThe integumentary system is the body’s first line of defense. It makes up 15% to 20% of the body’s weight. It protects the body from microorganisms, regulates temperature and provides vitamins. The epithelium comprises of cells that act as a barrier between the environment and the internal body organs though it may be found inside the body as well because of its ability to transport nutrients. The skin has three different layers, the epidermis; dermis and hypodermis.

1. Epidermis

It is the outermost layer which comes in contact with the environment. Its thickness can range from 0.04mm to 1.6mm. Desmosomes are found in the epidermis, these are points of attachment for cell-to-cell adhesion. The keratinocytes are the principal cell of the epidermis, they provide the keratin. When the skin is sloughed off, the epidermis regenerates providing a keratinized barrier. Melasnosomes synthesize melanin that is responsible for the skin color. The darker the skin color, the higher the number of melanin.


a)  Eccrine Glands

They are found all over the skin, they provide sweat, thereby causing thermoregulation. The secretion of sweat may be caused by heat and stress.

b)  Apocrine Glans

The role of this gland among humans has not been established. They secrete a milky substance that becomes odorous when in contact with bacteria. These glands function only after puberty.

c)  Sebaceous Glands

This gland releases sebum. Its function is to lubricate the skin. It causes acne among adolescents.

d)     Hair

Hair is a non-viable protein. It is normal to shed 50 to 100 strands of hair a day. The arrector pili muscles are responsible for goose bumps.

e)      Nails

They grow about 0.1mm per day. Distorted nails come from trauma or aggressive manicure. They grow slowly in cold weather and sickness.

2. Dermis

This is a dense layer of tissue directly underneath the epidermis. The thickness varies from 1mm to 4mm. It contains fibroblasts, macrophages, mast cells and lymphocytes which promote wound healing. The nerves vascular and lymphatic supplies are found in the dermis.


a) Papillary

It is the one in direct contact with the epidermis. It contains an increased amount of blood vessels, collagen, sweat glands and elastin.

b) Reticular

It contains collagen as well but it has mature elastic tissues. This layer comes in direct contact with the hypodermis.

The desmoepidermal region contains papillae which prevents the epidermis from coming off while the subepidermal basement membrane allows exchange of nutrients, waste products and metabolites.

3. Hypodermis

It is also called the adipose layer. It contains fat thus giving shape over the bone. This functions as a cushion from trauma, source of energy and insulation.

The integumentary system is rarely taken seriously, unlike the cardiovascular and the respiratory system. But, it may also have life threatening conditions such as skin cancer and burns. As a health care provider, it is our duty to teach our patient the function and importance of this body system.



I am Chadd Reyes, 21 years old. I graduated from Concordia College last 2011 as a Cum Laude. I passed the board exam last July 2011. I have been working as a volunteer nurse at Unciano General Hospital since March 2012. As a part time job, I work as a contractor for oDesk. I write articles for various medical topics.I have a passion for both Nursing and writing. I would enjoy being a nurse writer if given the chance. I want to impart my knowledge to my fellow and future colleagues.