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The Integumentary System

The net organ system we are going to take a look at is the integumentary system. The integumentary system refers to the body's external barrier, the skin. The skin is our largest organ. The integumentary system is also comprised of hair, sweat, and sebaceous glands.

The skin is a sensory organ and contains a lot of nerve endings for touch and pain. It has a major role in controlling body temperature by increasing or decreasing blood flow in the cutaneous vessels. It is an important barrier against pathogen exposure.

The epidermis is the superficial layer, the most outer layer of skin. The epidermis has many sublayers -

  • Stratum basale

  • Stratum spinosum

  • Astratum granulosum

  • Stratum lucidum

  • Stratum corneum

The epidermis also contains melanocytes which store melanin which gives skin and hair their colouring.

The next layer is the dermis and this layer mostly contains connective tissue. This layer contains collagen and elastin, which facilitates recoil in the skin and contributes to wrinkles.

The deepest layer is the hypodermis. This is a layer of loose connective tissue. This layer is for insulation. This layer contains the arrector pili muscle which is connected to the hair follicle. This muscle contracts due to the fight or flight response or to the cold, it causes the hair follicle to stand up and the skin to pucker, and goosebumps.

Take a look at our Freshers fear-fire for how burns affect the different layers of skin.

The skin contains numerous hair follicles which are important for thermoregulation and sensation.

Nails are also part of the integumentary system. They consist of keratin-filled scales.

Sweat glands are exocrine and they secrete sweat on the epithelial surface, there are two types of sweat glands, eccrine and apocrine. The majority of sweat glands are eccrine and can be found covering most of the body. The apocrine glands can be found in the groin and armpit region.

Sebaceous glands are another type of gland found in the integumentary system. They secret sebum, an oily substance that has a role as a barrier to the skin's immune system.

The integumentary system is extremely important, and like an onion it has many layers (for all you shrek fans out there).


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