My lecture about the Integumentary System.

1. The Integumentary
System
By WILLIAM M. BANAAG, R.N.

2. Integumentary System
 The organ system that protects
the body from damage,
comprising the skin and its
appendages (including hair,
scales, and nails), glands and
nerve endings.
 It distinguishes, separates,
protects and informs the animal
with regard to its surroundings.
 Small-bodied invertebrates of
aquatic or continually moist
habitats respire using the outer
layer (integument). This gas
exchange system, where gases
simply diffuse into and out of
the interstitial fluid, is called
integumentary exchange.

3. SKIN
 The skin is the outer covering of
the body
 In humans, it is the largest organ
of the integumentary system
made up of multiple layers of
epithelial tissues, and guards the
underlying muscles, bones,
ligaments and internal organs
 Human skin is like that of most
other mammals except that it is
not protected by a pelt and
appears hairless though in fact
nearly all human skin is covered
with hair follicles

4. Function of SKIN
 Protection: an anatomical barrier from pathogens and damage between the internal
and external environment in bodily defense;
 Sensation: contains a variety of nerve endings that react to heat and cold, touch,
pressure, vibration, and tissue injury.
 Heat regulation: the skin contains a blood supply far greater than its requirements
which allows precise control of heat loss by radiation, convection, conduction and
evaporation. Dilated blood vessels increase perfusion and heat loss while constricted
vessels greatly reduce blood flow in the skin and conserve heat.
 Aesthetics and communication: others see our skin and can assess our physical state
and attractiveness.
 Storage and synthesis: acts as a storage center for lipids and water, as well as a
means of synthesis of vitamin D (calcitriol) by action of UV on certain parts of the
skin.
 Excretion: sweat contains urea, however its concentration is 1/130th that of urine,
hence excretion by sweating is at most a secondary function to temperature
regulation.
 Absorption: Oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in
small amounts, some animals use their skin for their sole respiration organ. In
addition, medicine can be administered through the skin, by ointments or by means of
adhesive patch. The skin is an important site of transport in many other organisms.
 Water resistance: The skin acts as a water resistant barrier so essential nutrients
aren't washed out of the body.

5. SKIN Anatomy
 EPIDERMIS – the outer thinner
portion which is composed of
epithelial tissue
◦ Keratinocytes – produce the protein
keratin that helps waterproof and
protect the skin and underlying
tissues. It is the major epidermal
cell.
◦ Melanocytes – produces the pigment
melanin – a brown-black pigment that
contributes to skin color and absorbs
ultraviolet (UV) light from the sun.
◦ Langerhans cell – interacts with
white blood cells called Helper-T
cells in immune responses, and are
easily damaged by UV radiation.
◦ Merkel cell – located on the deepest
layer of epidermis (Stratum Basale).
It make contact with the ending of a
sensory neuron, and are thought to
function in the sensation of touch.

6. Layers of the Epidermis

7. Layers of the Epidermis
 Stratum Corneum
◦ consists of 25 to 30 rows of dead cells,
completely filled with keratin. Cells on this
layers are continuously shed and replaced
by cells from deeper strata. It serves as
an effective barrier against light and heat
waves, bacteria and many chemicals.
 Stratum Lucidum
◦ usually not present on hairy skin, only the
thick skin of the palm and soles has this
layer. It contains intermediate substance
that was formed from keratohyalin which
continually transformed to keratin.
 Stratum Granulosum
◦ develops keratohyalin – the precursor of
keratin.
 Stratum Spinosum
◦ tightly joins the lower and upper layer
together.
 Stratum Basale
◦ capable of continued cells division;
produces stem cells that produce and
multiply melanocytes and keratinocytes,
which push up toward the surface and
become part of the more superficial layer.

8. SKIN Anatomy
 DERMIS – composed of
connective tissue containing
collagen and elastic fibers.
It varies in thickness, very
thick in the palms and soles,
and very thin in the eye lid
and other parts of the body.
◦ Fibroblasts – cell that
produces collagen and elastic
fibers.
◦ Macrophages – cell of the
lymphatic which fights
bacteria.
◦ Adipocytes – cells that make
up the adepose tissue

9. Two Regions of the Dermis
 Papillary Region – the upper dermal
region. It is uneven and has fingerlike
projections from its superior surface
called Dermal Papilae.
◦ Dermal Papilae:
◦ Indents the epidermis above
◦ Contains capillary loop which furnish
nutrients to epidermis
◦ They are arranged in definite patterns on
the palm of the hands and soles of the
foot that form looped and whorled ridges
on the surface that increase friction and
enhance gripping ability of the finger and
feet
◦ The pattern is genetically determined.
 Reticular Layer – the deepest region.
◦ It contains blood vessels, sweat and oil
glands, and deep pressure receptors
(Pacinian Corpuscle) Sudoriferous
◦ Contains many phagocytes that act to (sweat) glands
prevent bacteria that managed to get Pacinian
through the epidermis from penetrating Sebaceous (oil) Corpuscle
any deeper into the body. glands
◦ Contains combination of collagen fibers
that strengthens the skin, and elastic
fibers that gives elasticity to the skin.

10. Skin Color
3 Pigments that Contributes
to Skin Color are:
 Melanin – located
mostly in the epidermis
 Carotene – mostly in
the dermis
 Hemoglobin – in red
blood cells within
capillaries in the
dermis.

11. Appendages of the Skin (HAIR)
 HAIR – composed of
columns of dead,
keratinized cells welded
together.
◦ its primary function is
protection, though limited.
 Hairs on the head guards
the scalp from injury and
the sun’s rays, it also
decreases heat loss.
 Eyelashes protects the eyes
from foreign particles
 Hairs in nostrils protects
against inhaling insects and
foreign particles.

12. Hair Color
 Due primarily to melanin in the
hair cortex and medulla
 Dark-colored hair contains
mostly true melanin
 Blond and red hair contain
variants of melanin in which
there is iron and more sulphur
 Graying of hair is the loss of
pigment believed to be the result
of a progressive decline of
tyrosinase – an enzyme
necessary for the production of
melanin.

13. Appendages of the Skin (GLANDS)
 Sebaceous (oil) Glands – produces sebum
which moistens hairs and waterproofs the
skin
◦ They are usually connected to hair follicles and
they are absent in the palm and soles
 Sudoriferous (sweat) Glands – produces
perspiration which carries small amount of
wastes to the surface and assists in
maintaining body temperature. Two types
of sudoriferous glands are:
◦ Apocrine Sweat Glands – are largely
distributed to the skin of the axilla, pubis and
areola; their ducts open into hair follicles; they
begin to function at puberty and produce a
more viscous secretion that eccrine sweat
glands; they are stimulated during emotional
stress and sexual excitement.
◦ Eccrine Sweat Glands – extensively
distributed to the entire skin except for the
margins of the lips, nail beds of the fingers and
toes, most parts of the genitals, and eardrums;
their ducts terminates at pores at the surface
of the epidermis; most numerous in the palms
and the soles; eccrine sweat glands function
throughout life and produce a secretion that is
more watery than that of apocrine sweat glands
 Ceruminous Glands – are modified
sudoriferous glands that produce cerumen,
they are found in the external auditory
meatus.

14. Appendages of the Skin (NAIL)
 NAILS – are plates of
tightly packed, hard,
keratinized cells of the
epidermis.
◦ Nail Body – is the portion of
the nail that is visible
◦ Free Edge – is the part that
may extend past the end of
the digit
◦ Nail Root – is the portion
that buried in a fold of the
skin.
◦ Lunula – the whitish
semilunar area of the nail.

15. Homeostatic Relationship Between
Integumentary System and Other Body System
 Endocrine System:  Nervous System:
 Skin protects endocrine organs  Cutaneous sensory receptors are located in the skin
 Androgens produced by the endocrine system activate  Nervous system regulates diameter of blood vessels
sebaceous glands and help regulate hair growth; in skin; activates sweat glands, contributing to
estrogen helps maintain skin hydration thermoregulation; interprets cutaneous sensation;
 Lymphatic System: activates arrector pili muscles.
 Aside from protection, it also prevents pathogen  Respiratory System:
invasion  Skin protects the respiratory organs
 Lymphatic system prevents edema by picking up  Respiratory system furnishes oxygen to skin cells and
excessive leaked fluids; immune system protects the removes carbondioxide via gas exchange with blood
skin cells  Cardiovascular System:
 Digestive System:  Aside from protecting the cardiovascular organs, skin
 Skin not only protects digestive organs, it also also prevents fluid loss from body surface; it also
provides vitamin D needed for calcium absorption serves as blood reservoir.
 Digestive system provides needed nutrients for the  Cardiovascular system transport oxygen and
skin nutrients to skin and removes wastes from skin; it
 Urinary System: also provides substances needed by skin gland to
make their secretions
 Aside from protection, skin also helps the urinary
system by excreting salts and some nitrogen wastes  Reproductive System:
thru sweating  Skin also protects reproductive organs; highly
 Urinary system activates vitamin D made by modified sudoriferous glands (mammary glands)
keratinocytes; disposes off nitrogenous wastes of produces milk. During pregnancy, skin stretches to
skin metabolism accommodate growing fetus.
 Muscular System:  During pregnancy, changes in skin pigmentation may
occur.
 Skin protects the muscles
 Skeletal System:
 Active muscles generate large amount of heat which
increase blood flow to the skin and may promote  Skin protects the bones; it also synthesizes vitamin D
activation of sweat glands of skin that bones needed for normal calcium absorption and
deposit of bone salts (calcium) which make bones
hard
 Skeletal system provides support for the skin.

16. ’
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Thank you
for
listening!!!