Table of Contents
- What is the Function of the Integumentary System?
- Integumentary System Organs and Structures
- Integumentary System Function
- Lesson Summary
The integumentary system is the organ system of the body that includes the hair, nails and skin. If you've ever had a cut or watched your hair or nails grow, you've been able to observe your integumentary system in action. There are four major structures of the integumentary system:
The next section covers each of these structures in more detail.
What are the three parts of the integumentary system? There are actually four main structures in the integumentary system, the skin, hair, nails and exocrine glands. Each plays a vital role in supporting the integumentary system's function of protecting the body.
The skin is the largest organ in the body and the largest part of the integumentary system. The skin has three main layers:
The epidermis is the outer, thinnest layer of the skin. It is composed of dead cells that face the extracellular environment and layers of additional cells underneath. One of the main types of cells in the epidermis is keratinocytes, which are dead at functional maturity and help form a barrier of the skin. The epidermis also contains melanocytes, which produce melanin for protection from ultraviolet rays from the Sun. There are also sensory cells and immune cells in the epidermis.
The dermis is the thick, middle layer of the skin. It contains two main layers, the papillary and reticular layers. The papillary layer is the thin upper layer made of loose connective tissue. The reticular layer is the deeper, denser layer filled with collagen fibers. Within the dermis are the sweat glands, muscles, hair follicles, nerves, and blood vessels.
The deepest layer of the skin is the hypodermis. The hypodermis is also called the subcutaneous fascia. It houses the adipose tissue of the skin and helps regulte temperature in the body. The hypodermis can also contain blood vessels and nerve endings as well.
Hair is an extension of the epidermis but originates from hair follicles in the dermis. A hair follicle is the tunnel extending through the epidermis and into the dermis where hairs grow from. Hair is made from dead skin cells that are immobilized with the protein keratin and are pushed upward from the hair follicle.
The availability of nutrients and hormones dictate the hair growing cycle, which switches through anagen, or growth, and telogen, or resting phases.
Nails are also made of keratin arranged in flat layers. Nail growth begins at the nail matrix under the nail bed. As new cells grow, older, keratinized cells are pushed out to form the nail. Nails grow relatively slowly, about 2.5mm per month.
There are two types of exocrine glands in the integumentary system:
Sebaceous glands produce oil in our skin. Sweat glands release water and salt in the form of sweat. These glands are found in the dermis of the skin.
The main purpose of the integumentary system is to help protect the body. However, the different organs in the integumentary system have different functions, which are described in detail below.
Skin is an essential organ in the body. Our skin protects us from the harsh external environment. It helps control water loss from the body and keeps the internal body in homeostasis compared to the external world. It also is the primary barrier that protects against pathogens getting into the body. Skin also regulates temperature homeostasis, keeping us warm with underlying layers of fat in the hypodermis and the function of hair in the dermis and epidermis. Cells inside the skin also use sunlight to produce vitamin D, which is essential for many functions in the body, including bone health.
Hair is important for regulating temperature homeostasis, increasing sensitivity to sensory input and provides mechanical protection for the skin. The arrector pillus muscles in the dermis control the angle at which the hair stands away from the skin to help regulate temperature through trapping air. Hair thickness varies to help protect the skin. For example, humans have thicker hair on the top of the head to protect the brain and skull from sun damage and heat loss. Other sensitive parts of the body, such as the genitals, are also protected with thick hair. Hair helps prevent pathogens from entering these delicate areas and keeps the skin moist and protected.
Nails help protect the fingers and toes, where they are found. With a hard covering, fingers are able to grasp and manipulate a variety of tools without damage to the hands. Nails also allow for increased dexterity and sensation.
Sweat glands are necessary for regulating temperature. The sweat induces evaporative cooling, where water evaporates from the skin, taking heat with it. This helps cool the body and maintains homeostasis. Sweat glands are also able to excrete metabolic waste in the sweat. Sebaceous glands produce oil in our skin and are helpful in regulating temperature, keeping our skin moist and hydrated and preventing bacterial growth.
The integumentary system is the body system that contains the skin, nails, and hair. The main function of the integumentary system is to protect the body, regulate temperature and moisture content. There are four main parts to the integumentary system:
The skin is the largest organ in the body and is responsible for regulating temperature, protecting the body and cushioning underlying structures. Hair is found almost all over the body and is an extension of dead skin cells. Hair protects our delicate skin and helps with temperature homeostasis. Nails are made of layers of keratinized cells and are used for protection of the fingers and toes. Exocrine glands are located in the dermis and include sweat glands which regulate temperature and secrete waste, and sebaceous glands which secrete oil to make the skin and hair waterproof.
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The main functions of the integumentary system are to protect the body from the environment. The integumentary system also helps with temperature homeostasis and sensing the environment.
The major organ of the integumentary system is the skin. The skin is made of three main layers, the epidermis, the dermis and the hypodermis.
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