THE INTEGUMENTARY SYSTEM
Objectives:
• Identify and describe the functions and structures of
the integumentary system
• Identify the medical specialists associated with the
integumentary system
• Recognize, define, spell, and pronounce the primary
terms related to the structures and function,
pathology, and the diagnostic and treatment
procedures of the integumentary system
THE INTEGUMENTARY SYSTEM
•Made up of the skin and its related structures
-the sebaceous glands
-the sweat glands
-hair
-nails
THE INTEGUMENTARY SYSTEM: FUNCTIONS
Skin:
• Waterproofs the body and prevents fluid loss
• Blocks the entrance of pathogens into the body
• Major receptor for the sense of touch
• Helps the body manufacture vitamin D from the sun’s
ultraviolet light
• Provides insulation and protection for underlying structures
THE INTEGUMENTARY SYSTEM: FUNCTIONS
Sebaceous glands:
• Secretes sebum (oil) that lubricates the skin and discourages
growth of bacteria
Sweat glands:
• Help regulate body temperature and water
content by secreting sweat.
• Eliminates small amounts of metabolic waste
THE INTEGUMENTARY SYSTEM: FUNCTIONS
Hair:
• Helps control the loss of body heat
Nails:
• Protects the dorsal surface of the last bone of
each toe and fingernail
• Also helpful in opening pop cans!
THE SKIN
Made up of 3 basic layers
1. The epidermis
2. The dermis
3. The subcutaneous layer
THE EPIDERMIS
The outermost layer of the skin, made up of several specialized
epithelial tissues
•Squamous Epithelial Tissue – forms the upper layer of the epidermis.
Flat, scaly cells that are continuously shed
•Basal Layer – the lowest layer of the epidermis. Cells are produced
and pushed upward to the surface where they die and become filled
with keratin
•Keratin- a fibrous water-repellent protein and a
primary component of the epidermis
•Melanocytes – cells found in the basal cell
layer, that produce and contain a dark brown to
black pigment called melanin
•Melanin – pigment that determines the color of
the skin. Also helps protect against some of the
harmful effects of Ultraviolet light
THE DERMIS
• The thick layer of living tissue directly below the epidermis
• Contains connective tissue, blood and lymph vessels, nerve
fibers and sensory nerve endings that detect touch, temp. pain,
and pressure
• Also contains the hair follicles and the sebaceous and sweat
glands
TISSUES WITHIN THE DERMIS
•Collagen – a tough yet flexible fibrous protein material found
in the skin, bones, cartilage, tendons and ligaments
•Mast cells – found in the connective tissue of the dermis.
They respond to injury, infection, or allergy by producing and
releasing substances including heparin and histamine
•Heparin – released in response to an injury, is an
anticoagulent (prevents clotting)
Why would we want our bodies to prevent clotting at an injury
site?
•Histamine – released in response to allergens, causes the
signs of an allergic response, including itching and increased
mucus secretion.
THE SUBCUTANEOUS LAYER
• Located just below the skin, connects the skin to the surface
muscles
• Made up of loose connective tissue and adipose tissue
• Lipocytes are predominant in the subcutaneous layer where
they manufacture and store large quantities of fat
Considering the subcutaneous layer’s primary component,
what protective functions does this layer serve?
THE SEBACEOUS GLANDS
• Located in the dermis layer of the skin and are closely
associated with hair follicles
• Secretes sebum through ducts opening into the hair
follicles where it moves onto the surface and lubricates the
skin and prevents drying out
• Sebum is slightly acidic and discourages the growth of
bacteria on the skin
THE SWEAT GLANDS
• Tiny coiled glands found on almost all body surfaces
• Most numerous in the palms of the hands, soles of
the feet, forehead and armpits
• Pores- the openings on the surface of the skin for the
ducts of the sweat glands
• Perspiration – (sweat) secreted by sweat glands and
is made up of 99% water plus some salt and
metabolic waste products
THE HAIR
• Rod-like structures composed of tightly fused, dead protein cells
filled with hard keratin
• The darkness and color of the hair is determined by the amount and
type of melanin produced by the melanocytes that surround the core
of the hair shaft
• Hair follicles – the sacs that hold the root of the hair fibers. The
shape of the follicle determines whether the hair is straight or curly.
• The Arrector pili – tiny muscle fibers attached to the hair follicles
that cause the hair to stand erect. In response to cold or fright, these
muscles contract, causing raised areas of skin known as goose
bumps. This reaction reduces heat loss through the skin
THE HAIR
• Although hair is dead tissue, it appears to grow because the cells
at the base of the follicle divide rapidly and push the old cells
upward. As cells are pushed upward, they undergo pigmentation
and harden
THE NAILS
•
Unguis – commonly known as a fingernail or toenail it is
the keratin plate protecting the dorsal surface of the last
bone of each finger and toe. Each nail consists of the
following parts:
1.
2.
3.
4.
5.
6.
Nail body
Nail bed
Free edge
Lunula
Cuticle
Nail root
ANATOMY OF THE NAIL