Transcript The Integumentary System

The Integumentary System
Chapter 36.3
• Organs are two or more tissues which
together perform a specialized function.
• Epithelial membranes are thin structures
that usually contain both epithelial and
connective tissue.
• Mucous membranes
– Line cavities that open to the exterior
– Layer of epithelium over connective tissue;
epithelium varies with location
– Tight junctions and goblet cells
• Cutaneous membrane is the skin
– the major organ of the integumentary system
• Integumentary system is the skin and the
organs derived from it (hair, glands, nails)
• One of the largest organs
– 2 square meters; 10-11 lbs.
– Largest sense organ in the body
• The study of the skin is Dermatology
Functions:
1. Regulation of body temperature
– Cellular metabolism produces heat as a
waste product .
– High temperature
• Dilate surface blood vessels
• Sweating
– Low temperature
• Surface vessels constrict
• shivering
2. Protection
physical abrasion
dehydration
ultraviolet radiation
3. Sensation
touch
vibration
pain
temperature
4. Excretion
5. Immunity/ Resistance
6. Blood Reservoir
8-10 % in a resting adult
7. Synthesis of vitamin D
uv light
aids absorption of calcium
Anatomy
• Epidermis
Skin
• Dermis
• Subcutaneous layer or hypodermis
Dermis
• Connective tissue layer
• Collagen and elastic fibers, nerves, blood
vessels, muscle fibers, adipose cells, hair
follicles and glands.
Accessory organs or epidermal
derivatives
• Hairs
– Epidermal growths that function in protection
– Shaft, root, and folllicle
– Sebaceous glands, arrector pili muscle, and
hair root plexus (touch)
– Hair growth and replacement have a cyclical
pattern
– ‘male-pattern’ baldness
Nails
• Plates of highly packed, keratinized cells
• Protection, scratching, & manipulation
• Formed by cells in nail bed called the
matrix ( in area of lunula)
• 1 mm / week
• Eponychium - cuticle
Skin Glands
• Sebaceous (oil) glands
– Usually connected to hair follicles
– Holocrine glands
– Fats, cholesterol, proteins, salts, and cell
debris
– Moistens hair and waterproofs skin
Skin color
• Genetic factors
– Same number of melanocytes
– Albinism
• Environmental factors
– Uv light or x-rays
Wound healing
• Inflammation
– Blood vessels dilate and become permeable
• Heat, redness, swelling and pain
• Shallow cuts
– Epithelial cells migrate
– Contact inhibition
Deeper wounds
• Inflammatory phase
– Fibrin forms clot
• Migratory phase
– Fibroblasts make granulation tissue
• Proliferative phase
• Maturation phase
• Scars – hypertrophic scar
– keloid
Burns
• First degree or partial thickness burn
– Only epidermis is damaged
– Erythema, mild edema, surface layer shed
– Healing – a few days to two weeks
– No scarring
• Second degree- deep partial-layer burn
– Destroys epidermis
– Blisters form
– Healing depends on survival of accessory
organs
– No scars unless infected
• Third degree or full-thickness burn
– Destroys epidermis, dermis and accessory
organs of the skin
– Healing occurs from margins inward
– Skin grafting may be needed
• Autograft
• Homograft
• Rule of Nines