Integumentary system: skin, hair, nails and glands


The integumentary system is made up of various organs and structures, including skin, hair, nails, glands, and nerves. The main function of the integumentary system is to protect the interior of the body from environmental elements such as bacteria, pollution, and ultraviolet rays from the sun.

The skin and its associated structures also retain body fluids, excrete waste products, and regulate body temperature. The integumentary system works with all the other systems of the body, such as the nervous, cardiovascular and digestive systems, to perform all the functions that it performs to help maintain the stability of the internal body.

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Integumentary anatomy

The integumentary system includes:

  • Leather
  • Hair
  • Nails
  • Exocrine glands
  • Sensory nerves


The skin is the largest and heaviest organ in the body. To act as a protective barrier, it must cover the entire body from the outside, from the crown of the head to the tips of the toes. The leather is approximately 2mm (0.079in) thick and weighs approximately 6lbs.

While there may be some differences in skin from one person to another (for example, in color, texture, and thickness), all skins share some basic similarities. For example, everyone's skin comes in different types, including:

  • Thick and Hairless – Located on frequently used parts of the body that cause severe friction (such as the soles of the feet and the palms of the hands).
  • Fine and Hairy: The most predominant type of body hair, it is found everywhere with the exception of thick, hairless skin.

Layers of fur

The skin consists of two layers:

  • Epidermis: The outer layer of the skin that forms a strong protective covering.
  • Dermis: located under the epidermis; Most of the skin structures are found in the dermis (for example, various types of glands and hair follicles).

The fat layer of the skin is a layer of subcutaneous tissue (under the skin), also known as the hypodermis. The fat layer has many different functions, including:

  • Provides a cushion for the skin.
  • Storage of fuel for the body (in the form of fat cells)
  • Body insulation to help maintain a stable temperature.


Hair is used to:

  • Help protect your skin
  • Regulate body temperature
  • Suitable for the evaporation and perspiration process.
  • It helps with the neurosensitive functions of the integumentary system.

Hair is made up mainly of fibrous proteins and contains very little lipids (fats) and water. Hair comes from follicles, which are simple organs made up of cells called epithelial cells. Epithelial cells are cells that line organs and function as a protective barrier.


Like other parts of the body, nails are made up of several segments, including:

  • Nail plate: the visible part of the nail.
  • Nail bed: the skin under the nail plate.
  • Cuticle – A thin strip of tissue that sits at the base of the nail and overlaps the nail plate.
  • Nail folds : skin folds located on the sides of the nail plate.
  • Lunula – a white crescent-shaped area located at the base of the nail plate.
  • Matrix: the invisible part of the nail, located under the cuticle, is the area responsible for the growth of the nail.

Nail function:

  • Protection: Protects fingers and toes from injury and injury.
  • Feel: helps to touch.


The integumentary system consists of four types of exocrine glands, which secrete substances outside the cells and the body.

The four exocrine glands associated with the integumentary system include:

  • Vascular glands: sweat glands, which are hollow cylindrical structures under the skin; they release sweat through very small holes in the surface of the skin. The sweat glands secrete sweat to cool the body when the temperature rises.
  • Sebaceous glands: Very small tubular glands located in the dermis that are responsible for secreting oil to the hair follicle to lubricate and protect the hair shaft, preventing it from hardening and becoming brittle.
  • Ceruminous glands: Located in the ear canal, the ceruminous glands work in conjunction with the sebaceous glands to produce earwax (medical-made earwax). Sulfuric acid plays an important role as a defense mechanism, keeping foreign invaders (such as bacteria and fungi) away and protecting the ear from any type of physical damage.
  • Breasts: There are two breasts, one on each side of the front of the chest wall. Both men and women have mammary glands, but in men these glands are underdeveloped. In women, the glands produce breast milk after delivery. In young females, the mammary glands have a semicircular shape, but then the glands begin to lose their shape. A single mammary gland weighs between 500 and 1000 grams (1.1 to 2.2 pounds).

Integumentary system function

In general, the integumentary system protects the body by creating a barrier against infection and protecting the body from changes in temperature and the adverse effects of potentially harmful substances (such as ultraviolet light).

The integumentary system performs many specific functions to help protect and regulate the internal functions of the body. Here are some of the ways the skin, nails, hair, glands, and nerves of the integumentary system work:

  • Helps protect body tissues and organs
  • Protects against infections and foreign invaders.
  • Protects the body from dehydration (due to accumulation of water)
  • Helps maintain a stable body temperature
  • Transport and eliminate waste
  • It does the work of pressure, pain, heat, cold or touch receptors.
  • Store fat for energy
  • It protects the body from injury and serves as a shock absorber (due to the fatty layer of the integumentary system).
  • Protects skin from damage caused by UV light from the sun (and other sources).

Protection against injury

The skin is made up of a very strong type of protein called keratin, which is the main type of skin in the outermost layer, the epidermis.

Keratin helps protect tissues, organs and structures from damage such as:

  • Cuts
  • Scratches
  • Abrasions

Fat layer protection

The fat layer of the skin helps protect underlying tissues and organs from injury by acting as a shock absorber, mitigating some types of injuries (such as those caused by blunt objects).

Protection against infection

The skin creates an acidic pH environment in which it is difficult for microorganisms to grow, thus protecting against infection.

Sweat proof

Sweat from the sweat glands prevents the overgrowth of microorganisms on the skin by producing a substance called dermcidin, which is an anti-infective agent with natural antibiotic properties.

Many different types of microorganisms are found on the skin, but these organisms cannot penetrate healthy skin. However, when a cut or other injury occurs that causes a hole in the skin, the organisms on the skin are no longer harmless as they penetrate the skin barrier.

This can cause an inflammatory reaction in the skin. The inflammatory response triggers the transport of white blood cells and other cells called macrophages, which are consumed by invading organisms.

UV protection

Not only does the skin provide a very strong barrier against infection in the body, it also prevents certain harmful substances from damaging the body, such as ultraviolet (UV) light from the sun (or other sources such as tanning beds).

The skin reacts to ultraviolet rays by producing the pigment melanin in cells called melanocytes. If there is excessive exposure to the sun, inflammation occurs and the skin becomes red and red in response to the dilation of the blood vessels in the dermis. As melanin is produced, the skin begins to tan; melanin absorbs ultraviolet light, preventing damage to the cell's DNA.

How hair protects your skin

One study found that hair also acts as a barrier against UV-B and UV-A radiation. Research has shown that the denser and thicker a person is, the better it protects hair from UV radiation.

Maintain body temperature

One of the most important functions of the skin is to maintain core body temperature.

The center of the brain that helps regulate temperature, called the hypothalamus, causes changes in the skin in response to changes in core body temperature.

V the abundant blood supply to the skin helps regulate temperature; As the blood vessels dilate, this leads to heat loss. When the vessels contract, the heat is retained. This process regulates core body temperature.

Sensory nerves

Sensory nerves are found in great numbers in the upper layer of the skin (epidermis); these nerves convey feelings:

  • Pain
  • Hot
  • Other skin sensations

Sign of malfunction of sensory nerves

When the sensory nerves in the skin are not working, the result is usually a tingling or burning sensation.

The dermis contains nerve endings and many sensory receptors. This allows the dermis to detect sensations such as pressure, heat, cold, and contact.

Nerve endings in the dermis sense sensation and therefore play a role in protecting the skin, sounding an alarm when the skin is exposed to things like possible burns.


Skin metabolism is the rate at which new skin cells are renewed; It occurs between epidermal and dermal cells, which work together to regulate collagen production and repair UV damage, aging, and other damage done to the skin.

Absorption and secretion

The skin is responsible for the removal of various substances, including:

  • Small amount of carbon dioxide
  • Sweat
  • Water
  • Waste (such as excess sodium chloride and urea)


The skin has been found to absorb a variety of substances.

A study published by the American Journal of Public Health found that the skin absorbs 64% of all contaminants found in ordinary tap water. The skin absorbs certain types of medications, including:

  • Hormones
  • Glyceryl trinitrate (for angina pectoris)
  • Wide range of other local medicine applications

Medications injected topically (through the skin) should be rubbed into the skin and covered with an occlusive dressing for optimal absorption.

The skin also accumulates certain substances, including:

  • Water that is absorbed and stored on the skin.
  • Nutrients like vitamin D

Interaction with other systems

The integumentary system works very actively with other organ systems to maintain the overall balance of the body (the so-called homeostasis). Examples of how skin helps all body systems maintain homeostasis include:

The immune system

The skin interacts with the body's immune system in many ways, protecting the body from infection by acting as a physical barrier against pathogens.

Digestive system

The skin synthesizes vitamin D (when exposed to the sun), thus providing this vital nutrient for the digestive system. Vitamin D is essential for the absorption of calcium and the skin interacts with the digestive system to ensure adequate absorption of calcium.

The cardiovascular system

The skin interacts with the cardiovascular system to help retain or generate heat by narrowing or dilating blood vessels.

Nervous system

The skin transmits sensations of the environment through nerve receptors. The nerve impulses (for example, the perception of pain, heat, cold, and other sensations) are then transmitted to the nervous system for the brain to interpret.

Musculoskeletal system

The synthesis of vitamin D that occurs in the skin favors the absorption of calcium. Calcium is essential for the growth and maintenance of bones and for muscle contraction.

Endocrine system

The endocrine system uses the body's hormones. Vitamin D, produced by the skin, can act as a hormone in the body. Certain hormonal imbalances can adversely affect the skin.

Respiratory system

The tiny hairs in the nose (which are part of the integumentary system) act as a filter to remove harmful particles that could otherwise enter the lungs.

urinary system

The skin removes waste products (such as salts and some nitrogen-containing wastes) in sweat; It helps the kidneys to maintain the correct balance of electrolytes in the body, as well as to maintain a normal pH balance.

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