Integumentary System Notes

Integumentary System Notes

• 1.
  Integumentary System Anatomy& Physiology Essentials of Human Anatomy & Physiology Seventh Edition
• 2.
  Skin Functions Aidsin heat regulation Synthesizes vitamin D Protects deeper tissues from : Mechanical damage - shape Antigens Thermal damage Ultraviolet radiation Dehydration
• 3.
  Skin Characteristics Skinis the largest organ in the body 25 square feet of surface area 40 pounds of skin shed in lifetime 30-40 thousand cells shed per minute 50 percent of heat lost through head 45 miles of nerves are in the skin 15 feet of blood vessels per 1 sq inch
• 4.
  Skin Structure Slide4.13b Figure 4.4
• 5.
  Skin Structure Epidermis – outer layer forms finger prints Stratified squamous epithelium Often keratinized (hardened by keratin) Dermis – middle bilayer Hypodermis Anchors skin to underlying organs Composed mostly of adipose tissue
• 6.
  Layers of theEpidermis Stratum basale - cells undergoing mitosis, contain melaninocytes Stratum spinosum Stratum granulosum Stratum lucidum - occurs only in thick skin Stratum corneum – Shingle- like dead cells
• 7.
  Melanin Pigment (melanin)produced by melanocytes Color is yellow to brown to black Melanocytes are mostly in the stratum basale Amount of melanin produced depends upon genetic and exposure to sunlight
• 8.
  Dermal Bilayer Papillarylayer Projections called dermal papillae Pain receptors Capillary loops Reticular layer Blood vessels Glands Nerve receptors
• 9.
  Dermal Structures Hairfollicle Dermal and epidermal sheath surround hair root Arrector pilli Smooth muscle Sebaceous gland Sweat gland Figure 4.7a
• 10.
  Dermal Oil GlandsSlide 4.15 Sebaceous glands Produce oil Lubricant for skin Kills bacteria Most with ducts that empty into hair follicles Glands are activated at puberty
• 11.
  Dermal Sweat GlandsSlide 4.16 Sweat glands Widely distributed in skin Two types Eccrine Open via duct to pore on skin surface Apocrine Ducts empty into hair follicles
• 12.
  Dermal Hair Scalp alone has 100,000 hairs Strands are produced by hair bulb 40-100 strands fall out each day Melanocytes provide pigment for hair color Blonds have more hair than dark
• 13.
  Skin Color DeterminantsSlide 4.14 Melanin Yellow, brown or black pigments Carotene Orange-yellow pigment from some vegetables Hemoglobin Red coloring from blood cells in dermis capillaries Oxygen content determines the extent of red coloring
• 14.
  Appendages of theSkin Nails Scale-like modifications of the epidermis Heavily keratinized Stratum basale extends beneath the nail bed Responsible for growth Lack of pigment makes them colorless
• 15.
  Nail Structures Slide4.22 Free edge Body Root of nail is where growth takes place Grow 1/8 inch per month Figure 4.9