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INTEGUMENTARY SYSTEM
INTEGUMENTARY SYSTEM
 The
cutaneous membrane
(SKIN), with various
accessory organs, makes up
the integumentary organs
system.
Types of Membranes
The three major types of epithelial
membranes are serous, mucous, and
cutaneous. These are usually thin
 Synovial Membranes we will discuss
further in Ch 8; but they line joints
and composed entirely of connective
tissues, they contain no epithelium.

Serous Membranes


Serous Membranes line the body cavities
that lack openings to the outside and
reduce friction between the organs and
cavity walls.
Consists of a layer of simple squamous
epithelium and a thin layer of loose
connective tissue.
Serous Membranes


Cells of a serous membrane secrete water
serous fluid, which helps to lubricate the
surfaces of the membrane.
They form the inner linings of the thorax
and abdomen, and they cover the organs
within these cavities.
Mucous Membrane



Line the cavities and tubes that open to the
outside of the body. These include the oral and
nasal cavities and the tubes of the digestive,
respiratory, urinary, and reproductive systems.
Consists of epithelium overlying a layer of loose
connective tissue (it can vary from location to
location)
Goblet cells within a mucous membrane secrete
mucus.
Cutanous Membrane

Is an organ of the integumentary
organ system and is more commonly
called skin. Which is what this
chapter is about…..
INTEGUMENTARY SYSTEM

The skin is one of the largest and
heaviest organ of the body. In an
average adult, the skin covers about 2
square meters (22 square feet), weights
4.5-5 kg (10-11 lb) and varies in
thickness (1.5 to 4.0 mm) depending on
what part of the body it covers.
INTEGUMENTARY SYSTEM

The skin covers all of the exposed
surface of the body and is continuous
with the mucous membranes lining
openings into the body surface, such
as those of the digestive, respiratory
and urogenital systems.
INTEGUMENTARY SYSTEM

The skin consists of 2 layers,

- 1 - the outer epidermis, derived from the
embryonic ectoderm and
- 2 - the inner dermis which develops from the
mesoderm.
The appendages of the skin such as hair,
nails, sebaceous glands and sweat glands
develop from the embryonic epidermis.


INTEGUMENTARY SYSTEM

Beneath the dermis is the hypodermis
(=subcutaneous tissue = superficial fascia)
which anchors the skin loosely to
underlying tissues (mainly muscles). The
hypodermis is NOT part of the skin
Epidermis


Epidermis is composed of stratified
squamous epithelium, it lacks blood
vessels.
See Pg 154 ….the layers of the epidermis
ranging from deepest to most superficial
are Stratum basale, Stratum spinosum,
Stratum granulosum, Stratum lucidum,
and Stratum corneum.
Epidermis

The stratum basale, is close to the dermis
and is the only part of the epidermis that
does have blood vessels. The cells of the
stratum basale are well nourished, as the
grow and enlarge they push older
epidermal cells away from the dermis
toward the surface of the skin. The further
the cells travel the poorer their nutrient
supply becomes.
Epidermis


The older cells go through a process called
keratinization which is when tough fibrous
strands of waterproof keratin proteins are
synthesized and stored within the cell
As a result layers of tough, tightly packed dead
cells accumulate in the epidermis; forming the
stratum corneum. These cells will eventually
shed off.
Epidermis


In healthly skin the production of new skin
cells usually balances with the loss of old
cells.
The rate of cell division will increase in
areas of the skin the undergo regular
friction…causing calluses and corns.
Epidermis

Melanocytes lie in the deepest section of
the epidermis and in the underlying
connective tissue…they are the only cells
that produce melanin….however they
sometime may be present in nearby
epidermal cells.
Dermis


The boundary between the epidermis and
dermis is usually uneven. This is because
the epidermis has ridges projecting inward
and the dermis has conical dermal
papillae passing into the spaces between
the ridges.
Fingerprints form from these undulations
of the skin.
Dermis



The dermis binds the epidermis to the
underlying tissue.
Composed of irregular dense connective
tissue that includes tough collagenous
fibers.
Contains muscles fibers (some smooth
some striated)
Dermis


Contains nerve fibers, moter fibers carry
impulses to dermal muscles and glands,
sensory fibers carry impulses away from
specialized sensory receptors.
One type of dermal sensory receptor,
Pacinian corpuscles, is stimulated by
heavy pressure. Meissner’s corpuscles,
senses light touch.
Subcutaneous Layer


Below the dermis; consists of loose connective
and adipose tissue. No sharp boundary
between dermis and subcutaneous layer.
The adipose helps to provide insulation by
conserving body heat. The amount various
greatly from individual to individual and body
part to body part. (abdominal v/s eyelids)
Subcutaneous Layer

This layer contains the major blood
vessels of that supply the skin.
INTEGUMENTARY SYSTEM

The skin and its appendages(hair,
nails, sebaceous and sweat
glands) make up a very complex
set of organs that accomplishes
several functions:
INTEGUMENTARY SYSTEM







- 1 - Protection: barrier against the outside
- 2 - Protection against dehydration
- 3 - Body Temperature Regulation
- 4 - Cutaneous Sensation
- 5 - Metabolic Functions
- 6 - Blood Reservoir
- 7 - Excretion
HAIR

The primary function of hairs is
protection: in human, hairs protect the
scalp from injury, from the sun ray and
decrease heat loss. Eyebrows and
eyelashes protect the eye from foreign
particles. Hairs in the nostrils filter the
air we inhale and hairs in the external
ear canal also prevent foreign particles
to penetrate there.
HAIR

Hairs are made of
dead keratinized
cells
HAIR


Usually grows for a time and then rests while it
remains anchored in its follicle.
A bundle of smooth muscle cells, forming the
arrector pili muscle attaches to the hair follicle,
the hair within the follicle stands on end when
the muscle contracts. If a person is upset or
cold nerve impulses may cause the arrector pili
muscle to contract….aka goosebumps.
NAILS
NAILS

Nails are hard plates
of tightly packed
keratinized cells.
They are clear and
cover the dorsal
surface of the last
phalanges of fingers
and toes.

Nails protect the the
ends of the fingers,
allow us to scratch
various parts of our
body and help us
grasping and
manipulating small
objects.
SEBACEOUS GLANDS
SEBACEOUS GLANDS

Sebaceous glands or oil glands are
simple branched areolar glands.
Functionally they are holocrine
glands. They secrete the sebum (seb
= oil) an oily product.
SEBACEOUS GLANDS

Sebum is usually
secreted into a hair
follicle but in a few
regions of the body
(lips and mammary
papilla for example)
they are directly
secreted onto the
skin surface.

Sebum is a natural skin
cream: it helps hair
from becoming brittle,
prevents excessive
evaporation of water
from the skin, keeps the
skin soft and contains a
bacterial agent that
inhibits the growth of
certain bacteria.
SEBACEOUS GLANDS
 Sebaceous
glands are scattered
all over the surface of the skin
except in the palms, soles and
the side of the feet.
SWEAT GLANDS

Sweat glands or
sudoriferous glands
are simple coiled
tubular glands. They
are divided into two
principal types:
eccrine and
apocrine.
Sweat Glands- Eccrine

Eccrine glands are the most

common/numerous. Their secretory
portion can be located in the dermis or in
the hypodermis.
They produce sweat, a watery mixture of
salts, antibodies and metabolic wastes.
Sweat prevents overheating of the body
and thus helps regulate body temperature.

Sweat Glands- Eccrine



Eccrine glands –respond throughout
life to body temperature elevated by
environmental heat or physical factors.
Glands are common on the forehead,
neck, and back.
They also cause the moisture that
appears on the palms and soles when a
person is emotionally stressed.
Sweat Glands-Apocrine

Apocrine glands are found mainly in the
skin of the armpits, of the anogenital areas
and of the areola of the breasts.

May develop a scent as they are
metabolized by skin bacteria (BO).

Their excretory ducts open into hair
follicles.
Sweat Glands-Apocrine



Their secretion is more viscous than
that of the eccrine glands.
They start secreting at puberty and are
also active during sexual arousal
Can wet certain areas of the skin when
a person is emotionally upset,
frightened, or in pain.
Heat Production and Loss

Because cellular
metabolism release
heat, the most active
cells are the major
heat producers,
skeletal and heart
muscle cells of
certain glands such
as the liver.


In intense heat nerve
impulses stimulate
structues in the skin
and other organs to
release heat.
The hypothalamus in
the brain controls the
body set point for
temperature.
Heat Production and Loss


Major sources of heat
loss in the body are
Radiation-infrared heat
rays escape from warmer
surfaces to cooler.
(Primary means of body
heat loss)
Conduction-body heat
moves directly from a
warmer surface to a
cooler object in contact
with its surfaces


Convection- heat loss by
conduction to the air.
Evaporation- body
temperature rises above
normal, stimulates
eccrine sweat glands to
release sweat, as it
evaporates it carries the
heat with it, cooling the
skin.
Skin Color


Regardless of racial orgin, all people have the
same number of melanocytes in their skin,
differences come from the amount of melanin
these cells produce which in controlled by
genes.
Environmental factors such as sunlight,
ultraviolet light and x rays can effect the skin.
The stimulate the melanocytes to produce more
pigment which make you tan.
SKIN COLOR

You will have to add the next few slides to
your notes…NOT on the guided reading.

Three pigments contribute to skin color



Melanin
Caroten
Hemolgobin
SKIN COLOR



Melanin- A polymer ranging in color from
yellow to reddish-brown to black
Humans have relatively the SAME number of
melanocytes, just depends on how much is
exposed.
Melanocytes are stimulated to greater activity
when we expose our skin to sunlight
SKIN COLOR
 Carotene-
yellow to orange
pigment. Found in carrots.
 Most obvious in the palms and
soles
Skin Color

Physiological
effect…when blood is
well oxygenated the
blood pigment
hemoglobin is bright
red making the skin of
fair complexioned
people appear
pink…blushing

When Blood oxygen
levels are low the
hemoglobin is dark
red, and the skin
appears bluish– a
condition called
cyanosis.
Healing of Wounds and Burns
 Skin,
injuries trigger
inflammation. The affected
area becomes red, warm
swollen, and tender.
CUTS

A cut in the
epidermis is filled in
by dividing
epithelial cells.
Clots close deeper
cuts, sometimes
leaving a scar where
connective tissue
replaces skin.

Granulations
form as part of
the healing
process.
Superficial Partial-thickness (First
Degree Burns)



A burn injuring only
the epidermis.
Healing usually
occurs within a few
days to two weeks.
Ex: Minor sunburn


Causes minor
discomfort and some
reddening of the skin
No blistering occurs,
No scarring and
actual tissue
destruction is
minimal.
Superficial Partial-thickness (First
Degree Burns)
(Deep) Partial-thickness (Second
Degree Burns)



A burn that destroys
some deep epidermis
as well as some
underlying dermis.
Most commonly occurs
as a result of exposure
to hot objects, hot
liquids, flames or
burning clothing.
The area is moist and
firm, may vary in color
from dark red to waxy
white.


Not complete
destruction of dermis
but often injuries
include hair follicles,
sweat glands, and
sebaceous glands.
It blisters, scarring
occurs, severe pain,
and generalized
swelling.
Partial Thickness Burn
Partial Thickness Burn
(Deep) Full-thickness
(Third Degree Burns)



A burn that is
characterized by
complete destruction of
dermis and epidermis.
Most commonly occurs
as a result of long
exposure to hot
objects, hot liquids,
flames, or chemicals.
The area becomes dry
and leathery, and it may
vary in color from red
to black to white.


Loss of nerve
endings cause an
insensitivity to pain.
Often skin grafts are
used to try to repair
loss tissue.
Full Thickness Burn
Full Thickness Burn
Electrical Burns

In electrical injures the damage begins in
the hypodermis and expands OUT.
Electrical Burns

Same injury days later…
Rule of Nines

As an aid for estimating the extent of
damage burns cause, the body is
subdivided into regions, each represent
9% ( or some multiple of 9%) of the total
skin surface area.
Terms that are
NOT in your Book!!

Pleurisy- a painful pathological condition
characterized by inflammation of the
serous membranes (pleura) that line the
chest cavity and cover the lungs. Pain is
caused by irritation and friction as the
lungs rub against the walls of the chest
cavity.
Terms that are
NOT in your Book!!



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Synovial membranes also line the small
cushion-like sacs called Bursae.
Strawberry hemangioma- a common collection
of dilated vessels that may initially appear as a
bruise at birth then grow rapidly during the first
year into a bright red nodule.
Any disorder of the skin is called dermatosis
Dermatitis- inflammation of the skin