Human Body Systems

1. Human Body Systems
How Does the Integumentary
System Work?

2. Introduction
Skin or integument has this very important role.
The largest organ of our body, the skin serves as
our outermost protective covering against
infection, abrasion and ultraviolet rays from the
sun.
The skin, sweat and oil glands, hair and nails
are the parts that compose our integumentary
system.

3. The Skin
This outermost protective
covering of our body is a sense
organ as well as an excretory
organ. The skin functions to
help regulate body
temperature.
The outermost layer is the
epidermis, the middle layer is
the dermis and the inner most
layer is the subcutaneous layer.

4. The epidermis is composed of compactly
arranged layers of flat and dead cells. A substance
called keratin fills these cells. Keratins prevents
water and microorganisms from entering the skin.
At the bottom layer of the epidermis are cells
that produce melanin pigment that determines
the color of our skin. This pigment helps protect
the skin by absorbing ultraviolet radiation from
the sun. The more melanin the skin has, the
darker is the skin color.

5. The dermis beneath the epidermis is composed of
living cells that contain collagen. The following
structures are found in the dermis: sweat glands, oil
glands, hair follicles, blood vessels and nerves. The
presence of may tiny nerve endings in this layer,
enables the skin to sense touch, pain, heat, cold and
pressure. Fingers and lips are more sensitive than
others because they contain more nerve endings.
Below the dermis is the subcutaneous layer. It is a
layer of fat which serves as storage of food and
energy. It also serves as an insulator of heat; meaning,
it prevents heat from escaping to help body warm.

6. Skin Glands
The skin has two main glands: the sweat
glands and the oil glands. The sweat glands
produce sweat or perspiration while the oil
glands secrete a greasy or oily substance called
sebum.
The sweat glands are small tubular structures
that are set deep in the lower dermis. The sweat
that is produced by these glands releases excess
water, salts and some body waste through the
pores of the skin. Sweat glands also serve to
regulate body temperature.

7. The oil glands are distributed throughout our
body except on the palms of our hands and the
soles of our feet. They are most abundant on the
scalp, face and neck. The sebum they secrete
lubricates our skin and prevents to much
evaporation of water from our skin. So our skin
is kept moist and soft. Sebum also keeps our hair
from drying and becoming brittle.

8. The Hair
The hair has two parts: the
shaft that protrudes from the
skin and the root that is
embedded in the skin. The
shaft is made up of keratin like
the epidermis. The root is
composed of an enlarged bulb
at the lower portion and an
elongated hair follicle.

9. Hairs found in different body parts have various
functions. Eyebrows protect the eyes by absorbing
and deflecting sweat. Hair on the face reduces the
skin’s exposure to harmful ultraviolet radiation.
Those in the nose and ears filter dust and other
foreign particles. Hair in the scalp protects the
head against abrasion.
The color of the hair is determined by different
types of melanin. The presence of more melanin
makes the hair darker. And the production of
melanin decreases with ages.

10. The Nails
Nails are flat, keratinized
cover at the tips of our fingers
and toes. The nails are formed
from the root cells in the
epidermis. They end as free
edges that overhang the tips of
the fingers and toes to protect
them from injury. There are
nerve endings under the nails
that make them function in the
sense of touch.

11. Disorders and Diseases of the Skin
Acne and Pimples
Acne is an eruptive skin disease
characterized by tiny swellings
or small bumps that include
whiteheads, blackheads and
pimples. It is usually caused by
clogging and inflammation of the
oil glands most commonly in the
skin of the face.

12. Disorders and Diseases of the Skin
Boils
They are hard, red painful
swelling that contains pus.
Commonly known as “pigsa”, it is
caused by bacteria that infect
hair follicles. The infection can
be cured by applying ichthyol
belladonna ointment.

13. Disorders and Diseases of the Skin
Scabies
It occurs as small itchy bumps
and rashes caused by itch mite. A
victim experiences intense
itching of the skin. Usually, the
affected parts are hands and
feet, inner part of the wrist and
the fold under arm.

14. Disorders and Diseases of the Skin
Fungal Infection
Some skin infections are caused by
microorganisms called fungi. “An-an”
or tinea flava appears white spots that
commonly infest the skin of the face,
arms and back. Athlete’s foot is
another fungal infection that occurs
mostly on the skin between toes and on
the soles. Ringworms makes the skin
scaly and produces rounded patches.

15. Disorders and Diseases of the Skin
Skin Cancer
Overexposure to sunlight is harmful to
our skin. The ultraviolet (UV) rays from
the sun causes skin aging, sunburn and
may even lead to skin cancer. UV
radiation may damage skin cells,
causing uncontrolled growth of
abnormal skin cells. The condition may
form tumors which later may develop
into skin cancer.