Integumentary
System
Chapter 5
Objectives
• Classify, compare the structure of, and
give examples of each type of body
membrane.
• Describe the structure and function of the
epidermis and dermis.
• List and briefly describe each accessory
organ of the skin.
Objectives
• List and discuss the three primary
functions of the integumentary system.
• Classify burns and describe how to
estimate the extent of a burn injury.
Terminology
• Integument is another name for the skin.
• Comprised of a group of simple,
functional, sheet like membranes.
– Found throughout the body.
• Two major categories:
– Epithelial membranes
– Connective tissue membranes
Epithelial Membranes
• Composed of epithelial tissue and an
underlying layer of special connective
tissue.
• Three types:
– Cutaneous Membrane
– Serous Membrane
– Mucous Membrane
Cutaneous Membrane
• Skin
• Largest and most visible organ in the
body.
– 16% of body weight.
Serous Membrane
• Simple squamous epithelium on a
connective tissue basement membrane.
• Two Types:
– Parietal – Lines the walls of a body
cavity.
– Visceral – Covers the surface of organs
within the cavity.
Serous Membrane
• Examples:
– Pleura
• Thoracic cavity
– Peritoneum
• Abdominal cavity
• Secretes a thin watery lubrication fluid to
help reduce friction between the organs
and the walls of the cavity.
Serous Membrane
• Conditions:
– Pleurisy
• Painful inflammation of
the chest cavity.
– Peritonitis
• Inflammation of the
abdominal cavity.
Mucous Membrane
• Line body surfaces that open directly to the
exterior.
• Produce mucous, a thick secretion that keeps
the membranes soft and moist.
• Examples:
– Respiratory
– Digestive
– Urinary
– Reproductive
Mucous Membrane
• Mucocutaneous junction – Transitional
area that serves as a point of “fusion”
where the skin and mucous membrane
meet.
Connective Tissue Membranes
• Do not contain epithelial
components.
• Produce a lubricant
called synovial fluid.
• Examples:
– Synovial membranes
lining a joint.
Skin
• Two primary layers:
– Epidermis
– Dermis
• Supported by a thick layer of loose
connective tissue subcutaneous layer.
– Insulates from heat and cold.
– Shock absorbing pad.
Epidermis
• Thinner, outermost layer.
• Composed of several layers of stratified
squamous epithelium.
– Stratum germinativum
• Innermost, that produces new cells
– Stratum corneum
• Outermost, keratin-filled cells
Epidermis
• Keratin
– Tough waterproof protein
• Soft – epidermis
• Hard – hair and nails
• Melanin
– Brown pigment produced by melanocytes.
– Absorbs harmful UV rays from damaging
underlying structures.
Dermis
• Deeper, thicker layer.
• Composed largely of connective tissue.
• Upper area has parallel rows of peg-like
dermal papillae
– Ridges and grooves form a unique
pattern.
• Finger prints
Dermis
• Deeper areas of the dermis contain tough
collagen protein material and elastic
fibers.
• Elasticity of the skin decreases with age
forming wrinkles.
Dermis
• Dermis also contains network of nerves
and nerve endings.
– Pain, Pressure, Touch, Temperature
• Muscle fibers
• Hair follicles
• Sudoriferous (Sweat) glands
• Sebaceous (Oil) glands
• Blood Vessel
Appendages of the Skin
• Hair
– Tube like structure called a follicle is
formed and hair is grown from a
cluster of cells called the papilla.
– Hair shaft is the visible portion, while
the hair root remains hidden.
– Arrector pili muscle will cause hair to
stand and goose bumps to form when
cold or frightened.
Appendages of the Skin
• Special Receptors
– Meissner’s corpuscle
• Detects light touch
– Pacinian corpuscle
• Detects pressure
– Krause’s end bulbs
• Low frequency vibrations
Appendages of the Skin
• Nails
– Hardened epidermal cells.
– Nail body is visible.
– Crescent moon shaped area near
the root is called the lunula.
– Root lies hidden by cuticle.
– Oxygen levels may be identified
by color of nail bed.
Appendages of the Skin
• Sudoriferous (sweat) gland
– Eccrine sweat gland
• Most numerous and wide spread
• Produces watery perspiration onto skin
surface to regulate body heat.
– Apocrine sweat gland
• Axilla and groin
• Produces thicker secretion and may have odor
due to breakdown of secretion by bacteria.
Appendages of the Skin
• Sebaceous (oil) gland
– Secrete an oil called sebum to lubricate
hair and skin.
– Regulated by sex hormones
– Increased production at adolescence
forming pimples or blackheads.
Function of the Skin
• Protection
• Temperature Regulation
• Sense Organ
Protection
• Acts as the bodies first line of defense.
• Protects against:
– Infection by pathogens
– UV rays from the sun
– Harmful chemicals
– Physical trauma
Temperature Regulation
• Skin releases almost 3,000 calories of
body heat per day.
• Regulation of sweat.
• Regulation of blood flow near surface of
skin.
Sense Organ
• Skin functions as enormous sense organ
keeping the body informed about its
environment.
• Pressure
• Pain
• Touch
• Temperature
Burns
• Most serious and frequent problems of
the skin.
• Caused by:
– Fire or hot surface
– Overexposure to UV light
– Chemical or acids
Burns
• Treatment and survival depend on the
total area of the body burned and the
depth of the burn.
• Body surface estimated by “Rule of
Nines”.
• Degree of burn
Rule of Nines
• Body divided into 11
areas of 9% each.
– 1% for groin
area.
Degree of Burns
• First-degree burn
– Burn involving only the surface layers of
the epidermis.
– Minor discomfort and reddening.
– No blistering, but may peel.
• Sunburn
Degree of Burns
• Second-degree burn (partial-thickness)
– Burn involving deep layers of the
epidermis and upper layers of dermis.
– Blisters, severe pain, swelling, and damage
to glands or hair follicles.
– Scarring is common.
Degree of Burns
• Third-degree (full-thickness) burn
– Complete destruction of epidermis, dermis,
and even subcutaneous layers, muscle, or
bone.
– “Painless” burn as the nerve endings are
destroyed.
– Great risk of infection.
Questions?