The integumentary system is made up of the skin as well as its appendages that act to protect the body from different kinds of damage, like loss of water or damages from the outside. The integumentary system includes scales, feathers, nails, hair, and hooves.
Its main function is to act as a barrier to protect the body from the outside world. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature. In order to do these things, the integumentary system works with all the other systems of your body, each of which has a role to play in maintaining the internal conditions that a human body needs to function properly.
The integumentary system has many functions, most of which are involved in protecting you and regulating your body’s internal functions in a variety of ways:
Your body is a complicated system that consists of many subsystems that help to keep it functioning properly. These subsystems serve a variety of purposes and require needed materials to function properly, as well as means of communicating information to other parts of the body. Thus, the skin and other parts of the integumentary system work with other systems in your body to maintain and support the conditions that your cells, tissues, and organs need to function properly.
The skin is one of the first defense mechanisms in your immune system. Tiny glands in the skin secrete oils that enhance the barrier function of the skin. Immune cells live in the skin and provide the first line of defense against infections.
By helping to synthesize and absorb Vitamin D, the integumentary system works with the digestive system to encourage the uptake of calcium from our diet. This substance enters the bloodstream through the capillary networks in the skin. The healthy functioning of your skin also is related to the digestive system because the digestion and assimilation of dietary fats and oils are essential for the body to be able to make the protective oils for the skin and hair.
The integumentary system also works closely with the circulatory system and the surface capillaries through your body. Because certain substances can enter the bloodstream through the capillary networks in the skin, patches can be used to deliver medications in this manner for conditions ranging from heart problems (nitroglycerin) and smoking cessation (nicotine patches).
This skin also is important in helping to regulate your body temperature. If your too hot or too cold, your brain sends nerve impulses to the skin, which has three ways to either increase or decrease heat loss from the body’s surface:
Your skin plays a vital role in your body as regards the sense of touch. The nervous system depends on neurons embedded in your skin to sense the outside world. It processes input from your senses, including touch, and initiates actions based on those inputs.
As well as interacting with the body systems, the integumentary system also contributes to numerous physiological processes, especially those involved in the regulation of the body’s internal environment so as to maintain a stable condition. For example, skin helps in temperature regulation by changes in the pattern of blood supply to the skin and by sweating.
It is the body’s largest organ. The average square inch of skin has 20 blood vessels, 650 sweat glands, and more than a thousand nerve endings. Skin is 12-15% of our body weight with a surface area of 1-2 meters. The skin has three layers – epidermis, dermis and hypodermis.
Epidermis
The top layer of the skin is the epidermis. It is made up of epithelial cells. It does not have blood vessels. Its major functions are, absorption of nutrients, homeostasis and protection.
It provides the initial barrier from the external environment. The basement membrane separates the epidermis from the dermis.
The epidermis contains melanocytes that are responsible for giving color to the skin. Nerve endings are found in the deepest layer of the epidermis.
The main cell of the epidermis is known as the keratinocyte. Keratinocyte produces keratin, which is a fibrous protein that helps in the protection of the skin. Keratin is also a waterproofing protein. Most body skin is keratinized. The only body skin that is not keratinized is the mucous membrane lining, like the inside of the mouth.
The protein keratin is also responsible for stiffening epidermal tissue in order to form fingernails. Nails grow from the nail matrix. The nails grow at an average of 1mm per week.
Dermis
Below the epidermis is the dermis. It is the middle layer of the skin that is made up of dense irregular connective tissue as well as areolar connective tissue like collagen with elastin arranged in a pattern that is diffusely bundled and woven.
The dermis has got two layers:
These layers give elasticity, therefore, allowing the skin to stretch and at the same time resist sagging, wrinkling, and distortions. The dermal layer also provides the site for nerve endings and endings for blood vessels.
Hypodermis
The deepest layer of the dermis is the hypodermis. It is made up of adipose tissue. Collagen bundles join the dermis to the hypodermis in a manner that allows most skin areas to move freely over the tissue layers that are found deeper.
This layer is also known as the subcutaneous layer. It is a layer below the skin that is attached to the dermis by elastic fibers and collagen. It is made up of cells known as adipocytes that are specialized in the accumulation and storage of fats.
This layer acts as an energy reserve. The fats that are contained in the adipocytes may be put back into circulation through the venous route during intense effort or when there is a lack of substances that provide energy.
Hair is a fiber that is found only in mammals. It consists mainly of keratin-producing keratinocytes. Each hair grows out of a follicle in the dermis. By the time the hair reaches the surface, it consists mainly of dead cells filled with keratin. Hair serves several homeostatic functions. Head hair is important in preventing heat loss from the head and protecting its skin from UV radiation. Hairs in the nose trap dust particles and microorganisms in the air and prevent them from reaching the lungs. Hair all over the body provides sensory input when objects rush against it or it sways in moving air. Eyelashes and eyebrows protect the eyes from water, dirt and other irritants.
Fingernails and toenails consist of dead keratinocytes that are filled with keratin. The keratin makes them hard but flexible, which is important for the functions they serve. Nails prevent injury by forming protective plates over the ends of the fingers and toes. They also enhance sensation by acting as a counterforce to the sensitive fingertips when objects are handled. In addition, fingernails can be used as tools.
The below illustration shows the nail structure.
