Integumentary System

Ch 12 IVY TECH/ Chapter16 Book

Anatomy/accessory structures/pathology/lab tests/procedures/Terminology

What makes up this system? Just SKIN? NO!


The integumentary system is an organ system consisting of the skin, hair, nails, and exocrine glands.

The skin is only a few millimeters thick yet is by far the largest organ in the body. The average person’s skin weighs 10 pounds

Skin forms the body’s outer covering and forms a barrier to protect the body from chemicals, disease, UV light, and physical damage.

Hair and nails extend from the skin to reinforce the skin and protect it from environmental.

Cells in the epidermis are called squamous cells*

1 Protects against fluid loss and secretions are acidic to fight off infection-Langerhans cells

2 Secretes sweat and sebum, which is an oily substance to lubricate skin,and sweat cools the body.

3 Receptors for pain, temperature, pressure, and touch, nerve cells relay messages to brain and spinal cord

4 Thermoregulation to maintain body temp by sending msgs to brain that tell body to warm up or to sweat and carry heat away from body.

The skin is one of the first defense mechanisms in your immune system

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.

The integumentary system also works closely with the circulatory system and the surface capillaries through your body

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

Anatomy of Skin

Skin has three layers:

  • The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone. Lacks blood vessels so it depends on deeper layers of skin (dermis) for nourishment.
  • The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands.
  • The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.
  • Epidermis

The skin’s color is created by special cells called melanocytes, which produce the pigment melanin.

Melanocytes are located in the  basal layer or deepest layer of epidermis. This production increases with exposure to uv light.

GIRLS!! Suntan is a protective when melanin cant absorb all rays sun becomes red and burns. Dark skinned people have more melanin so not as much burning or skin cancer!


The dermis is a layer of skin between the epidermis and

* subcutaneous tissues, that consists of connective tissue and cushions the body from stress and strain.

Structural components of the dermis are collagen*, elastic fibers, and also contains Mechanoreceptors that provide the sense of touch and heat, hair follicles, sweat glands, sebaceous glands,lymphatic vessels and blood vessels. Those blood vessels provide nourishment and waste removal for both dermal and epidermal cells.

Subcutanous layer of skin

Subcutaneous fat

The bottom layer of skin is the subcutaneous fat layer.

  • Attaching the dermis to your muscles and bones: This layer has a special connecting tissue.
  • Helping the blood vessels and nerve cells: Blood vessels and nerve cells that start in the dermis get bigger and go to the rest of your body from here.
  • Controlling your body temperature: The subcutaneous fat is the layer that helps keep your body from getting too warm or too cold.
  • Storing your fat: This fat pads your muscles and bones and protects them from bumps and falls.

Accessory Structures
Hair and Nails

Hair and nails fun facts

  • It's normal to lose 50 to 100 hairs a day but anyone who notices thinning hair should see a dermatologist.
  • Hairstyles that pull the hair, like ponytails and braids, can cause hair loss. Cutting rate has nothing to do with rate of growth!
  • Fingernails grow 0.1 millimeters each day and toenails grow 1 millimeter a month. Fingernails grow faster than toenails, and nails grow faster during the summer than the winter.


5 million hairs on the body--100,000 on your head!

Hair is simple in structure, but has important functions in social functioning.

Hair is made of a tough protein called keratin.

A hair follicle anchors each hair into the skin. The hair bulb forms the base of the hair follicle.

In the hair bulb, living cells divide and grow to build the hair shaft.

Blood vessels nourish the cells in the hair bulb, and deliver hormones that modify hair growth and structure at different times of life.


The fingernail is an important structure made of keratin that has 2 purposes. The fingernail acts as a protective plate and enhances sensation of the fingertip. The protection function of the fingernail is commonly known, but the sensation function is equally important.


cyanosis-Cyanosis: A bluish color of the skin and the mucous membranes due to insufficient oxygen in the blood.

Nail Plate

The nail plate is the actual fingernail, made of translucent keratin. The pink appearance of the nail comes from the blood vessels underneath the nail.

. The cuticle is situated between the skin of the finger and the nail plate fusing these structures together and providing a waterproof barrier.


The perioncyhium is the skin that overlies the nail plate on its sides. It is also known as the paronychial edge. The perionychium is the site of hangnails, ingrown nails,  .

lunula  small crescent-shaped structure or marking, especially the white area at the base of a fingernail that resembles a half-moon.


OIL or sebaceous gland, gland in the skin of that secretes an oily substance called sebum. In humans, sebaceous glands are primarily found in association with hair follicles but also occur in hairless areas of the skin, except for the palms of the hand and soles of the feet.

Sebum is a mixture of fat and the debris of dead fat-producing cells. EEWW, sorry.  . Generally the sebum is deposited on the hairs inside the follicles and is brought up to the surface of the skin along the hair shaft. In hairless areas, the sebum surfaces through . Sebum lubricates and protects the hair and skin and prevents drying and irritation of membranes.

Sebum may collect excessively as a result of poor hygiene, a diet rich in fats, or accelerated glandular activity, especially during adolescence. Excessive secretions of sebum may be related to acne.

sebaceous gland." The Columbia Encyclopedia, 6th ed.. 2014. 14 Feb. 2015

Sweat gland: The sweat glands are small tubular structures situated within and under the skin (in the subcutaneous tissue). They discharge sweat by tiny openings in the surface of the skin.pore

2 kinds eccrine and apocrine

Eccrine-Everywhere! tiny,

apocrine-After puberty-larger,armpits, genitals, odorless, it mixes w/ bacteria then you get ODOR

The sweat is a transparent colorless acidic fluid with a peculiar odor.  fatty acids and  It is also called perspiration

SKIN Pathology

Lesion-area of abnormal tissue from disease or trauma


albino- The word “albinism” refers to a group of inherited conditions. People with albinism have little or no pigment in their eyes, skin, or hair. They have inherited altered genes that do not make the usual amounts of a pigment called melanin. One person in 17,000 in the U.S.A. has some type of albinism. Albinism affects people from all races. Most children with albinism are born to parents who have normal hair and eye color for their ethnic backgrounds.

Alopecia-absence of hair where it normally grows

petechiae-small pinpoint hemmorhage

pruritis- itching from stimulation in nerves in skin caused by substances released in allergic reaction

acne-buildup of sebum, eruption of skin


Gangrene-death of tissue from no blood! black

Lupus-chronic autoimmune inflammatory disease of collagen, in skin joints and internal organs


Callus-growth of keratin in epidermis caused by pressure or friction

Keloid scar


Basal cell is most common form of skin cancer


Cryosurgery- use of nitrogen to freeze tissue and destroy

sample skin for analysis and take pus or fluid samples and send to lab

Skin biopsy- punch or shave we use Bx as biopsy in healthcare

Treatment for skin cancer- surgery to remove, radiation, chemotherapy, cryosurgery