Integumentary System - Notes Notes Integumentary System...

Unformatted text preview: Notes Notes Integumentary System Chapter 36 Section 3 Lecture Outline – Integumentary System PowerPoint Notes textbook questions Keys Keys Functions Functions 1. Covers and protects the body What does the skin protect us from? – Pathogens – Injury – Ultra­violet radiation Functions Functions 2. Regulate body temperature How does it regulate temperature? – Sweating – Dilate/constrict of blood vessels – Goose bumps Functions Functions 3. Excretes Waste What wastes are excreted? Urea as sweat subcutaneous Functions Functions 4. Reduces water loss Keeps the body from drying out! Functions Functions 5. Houses sensory receptors Chemo Mechano Chemo Photo Mechano There are 2 main layers of skin There I. Epidermis II. Dermis Epidermis Stratum corneum Outer (surface) layers of skin Dead keratinocytes Stratum lucidum 10­30 cells thick Stratum granulosum Two Parts: Inner part composed of Stratum spinosum Lamellar granules Keratinocyte Langerhans cell living cells Outer part is of dead cells Stratum basale Dermis Melanocyte Merkel cell Tactile disc Sensory neuron Epidermis – Inner layers Epidermis Lowest layer of cells reproduce and push older cells toward the surface. As cells near the surface, they flatten and their organelle disintegrate Epidermis – Inner layers Epidermis These cells also begin producing Keratin a tough, fibrous protein. This replaces cytoplasm. Epidermis – Outer layers Epidermis The Keratin producing cells die as they move toward the surface. Outer dead layer waterproofs and protects inner layers It is shed continually and is completely replaced in 2 ­ 4 weeks Epidermis Epidermis What do we find in the epidermis? Melanocytes What are melanocytes? Cells that produce melanin. What is melanin? A dark brown pigment What does melanin do? Gives skin it’s color Protects sensitive dermis from U­V radiation Epidermis Epidermis Melanocytes Do some people have more melanocytes than other people? Epidermis Epidermis Skin pigmentation is due to the type and amount of melanin produced Eumelanin produces darker pigments Phaeomelanin produces lighter pigments and freckles These often occur together in varying amounts Melanocyte Dermis Dermis Deeper layers of skin 10­20 times thicker than epidermis. Top layer arranged In ridges. Why are there ridges? Dermis Dermis Dermis Ridges help the epidermis bind to the dermis. The uneven ridges create fingerprints Dermis Accessory Organs of the Dermis Accessory 1. Hair follicles – tube­like depression where the hair develops Accessory Organs of the Dermis Accessory 2. Sebaceous glands – secret oily sebum to soften and waterproof skin Accessory Organs of the Dermis Accessory 3. Nails – protective covers of ends of fingers and toes. Accessory Organs of the Dermis Accessory 4. Sweat glands: – secrete waste – regulate heat – produces ear wax – produces milk during lactation Accessory Organs of the Dermis Accessory 5. Blood vessels – to nourish skin cells Accessory Organs of the Dermis Accessory 6. Nerves – to send and receive messages Subcutaneous Accessory Organs of the Dermis Accessory 7. Erector pilli muscle ­smooth muscle ­causes “goosebumps” ­causes hair to stand erect subcutaneous Subcutaneous layer – connective tissue tissue Anchors dermis to the body Contains fat cells to protect and cushion Subcutaneous layer Self Quiz Self L. M. A. K. B. J. C. I. H. G. F. E. D. I. Blood vessels H. Connective tissue B. Dermis A. Epidermis G. Fat cells L. Hair J. Hair follicle F. Muscle D. Neuron K. Sebaceous gland C. Subcutaneous layer Sweat gland E. Sweat pore M. Disorders of the Skin Disorders Acne – infection of sebaceous gland Disorders of the Skin Disorders Benign tumor – fleshy growths on neck, armpits and body. Harmless! Tumor Disorders of the Skin Disorders Vascular Birthmarks – Blood vessel abnormality affecting .5% of population – darkens skin Disorders of the Skin Disorders Dermatitis – dry, sensitive skin Disorders of the Skin Disorders Nail Fungus Disorders of the Skin Disorders Fungal infections Athlete’s Foot Ring Worm Disorders of the Skin Disorders Impetigo – bacterial infection Disorders of the Skin Disorders Psoriasis – chronic inflammation Disorders of the Skin Disorders Cancer Carcinoma Melanoma Disorders of the Skin Disorders Warts­ viral infection Common wart Plane warts Plantar wart Disorders of the Skin the Burns First degree Second degree Third degree Interesting Tidbits Interesting Your body is composed of approximately 100 Trillion cells About 16% of your body weight is skin The skin is completely renewed every 27 days You will make almost 1000 new skins in a lifetime If all the layers of your skin were laid out on the ground, it would cover about 20 m2 or 2 parking spaces Interesting Tidbits Interesting A fingernail or toenail takes about 6 months to grow from base to tip Fingernails grow faster than toenails An average human scalp has 100,000 hairs We lose between 40 and 100 hairs per day Blondes have more hair than brunettes Interesting Tidbits Interesting Fingerprints provide traction for grasping objects Even identical twins have different fingerprints Every square inch of dermis contains twenty feet of blood vessels Skin on our hands and feet is thicker. When we bathe, skin takes on water and swells slightly. In the thicker areas, increased surface area creates crowding. The skin must wrinkle to accommodate the changes Interesting Tidbits Interesting Friction of the epidermis causes cell division to increase. This outward thickening is called a callous. Sometimes growth is inward, creating a corn. Humans shed about 600,000 particles of skin per hour – about 1.5 pounds per year. At age 70, you will have lost about 105 lbs of skin. ...
View Full Document