The Integumentary System

Parts of the Integumentary System

  • Skin

  • Nails

  • Hair

  • Glands

Functions of the Integumentary System

  • Protection

  • Waste Removal

  • Temperature Regulation

  • Waterproof

  • Ability of Sensory

  • Vitamin D Synthesis

  • Energy Storage

FUN FACT! Skin accounts for about 15% of your body weight! 1

The Skin, Glands, and Hair

The Skin:

The skin protects the inside of the body from damage, such as a fire. It also functions as a shock absorber and helps protect from bacteria, viruses, and UV rays. However, it does let some UV rays in, so vitamin D can be made.

The 3 layers of the skin are the epidermis, the dermis, and the hypodermis.


  • The epidermis contains five layers (from superficial to deep) the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and the stratum basale. One memory cue for these layers from superficial to deep could be "Cows Love Grass Simply Because."


  • The dermis is the thickest layer of skin. It contains collagen and elastin which help it support the overall structure of the skin. It also contains many structures as labeled in the above model. Some of the structures are described in detail below.

-The Arrector Pili Muscle:

The arrector pili muscle's function is to control hair movement. The nerves allow for skin to be able to have sensory. When the sensory nerve fibers in the dermis and epidermis sense "cold", the arrector pili muscle might pull the hair root in the dermis upright causing the hair shafts in the epidermis to "stand up." This causes the hair on your arms to "stand up" when you are cold.

-The Hair:

Hair helps protect against UV rays.

The hair shaft is the portion of the hair strand you see on your skin. The hair root is the portion in the dermis. The hair follicle allows the hair to grow. It can also help the skin heal after an injury.

-The Glands:

There are many types of glands within the integumentary system.

The sudoriferous glands helps produce sweat for the skin (the eccrine sudoriferous gland) and hair (the apocrine sudoriferous gland). This helps protect against pathogens: dermcidin is a natural anti-infective found in your sweat that protects against microorganisms building up on skin. The sudoriferous glands also help to "sweat out" excess salt, sugar, urea, and ammonia. The sudoriferous glands aid in temperature regulation as well by pumping sweat in order to cool down the body at times.

The sebaceous (oil) glands help produce oil for the hair and skin. This allows for the skin to be hydrophobic (water-resistant) and the hair to be somewhat waterproof.

There are other types of glands in the integumentary system which are not shown in the model above. Ex: The ceruminous gland. These glands are only found in ear canals and produce ear wax. The mammary gland. These glands produce milk in the breasts of those assigned female at birth after they give birth.

-The Cutaneous Vascular Plexus:

The dermis also contains the cutaneous vascular plexus which are pairs of arterioles ("miniature arteries") and venules ("miniature veins") which are connected through capillaries. This allows for blood circulation; for a brief overview on blood circulation, visit "SYSTEMIC Circulation:" under "2) The Pathway of Blood + Circulatory Systems."


  • The hypodermis, also known as the subcutaneous layer, is the deepest layer of skin. The hypodermis has a lot of connective tissue; adipose tissue, commonly known as body fat, is one type of connective tissue found in the hypodermis. Adipose tissue helps insulate the body and also helps store energy. Collagen is also found in the hypodermis; it is a fibrous connective tissue protein which helps provide elasticity and structure. Blood vessels are also found in the hypodermis, so the hypodermis can supply blood to the dermis, so circulation can happen.

A Team Player

The integumentary system works with other systems in order to ensure a functioning body. Some examples are listed below.

  • As mentioned earlier, the skin makes vitamin D which is needed for calcium to be absorbed. The digestive system helps absorb calcium. This can help the muscular and skeletal systems (the musculoskeletal system) as calcium is needed to maintain bones and is also necessary for muscle contraction.

  • Hair is located in the nostrils to prevent from inhaling dangerous particles which could have been taken into the lungs. This helps the respiratory system to do its job.

  • The glands in the skin produce sweat which helps "sweat out" waste products such as salt. This helps the urinary system's kidney maintain a healthy balance of water, salts, and minerals.

The Nail

The nail helps to protect the end of the finger from damage; it is made of keratin.

  • Nail Matrix: New cells are made here. These new cells push out the old dead cells, and this is exactly how the nail grows and is replaced when cut.

  • Eponychium Cuticle and Nail Folds: Together, these secure your nail and also protect it from microorganisms.

  • Nail Bed and Hyponychium: The nail bed protects from infection by ensuring pathogens do not get to the skin under the nail. The hyponychium also protects against external debris from getting under the nail.

  • Stratum Germinativum: This contains cells which divide in order to replenish the epidermis of the fingertip.


More on Nails:


Do Your Fingernails Grow Faster On Your Dominant Hand?