The Integumentary System-Hair Latest Update Graded A

The Integumentary System-Hair Latest Update Graded A Epidermal Derivatives organs that develop from embryonic epidermis -hair, nails, glands, nerves Function of Hair Protection: -protects scalp from sun -eyebrows and eyelashes protect eyes -nostril hair protects against inhaling particles Effect on rate of growth/replacement -illness -diet (rapid weight loss) -high fever -surgery -blood loss -severe emotional stress Anatomy of Hair composed of columns of dead, keratinized cells welded together Shaft superficial portion that projects from the surface of the skin Root portion below surface that penetrates into dermis and sometimes subcutaneous layer 3 Concentric Layers 1. Medulla 2. Cortex 3. Cuticle Medulla inner layer, contains pigment Cortex middle layer, contains pigment Cuticle outer layer Dark Hair mostly melanin Blonde Hair more sulfur in melanin Red Hair more iron in melanin Grey Hair loss of pigment due to decline in melanin White Hair accumulation of air bubbles in shaft Hair Follicle surrounds root of hair Bulb found at base of hair follicle, house papilla of hair matrix Papilla of Hair structure that contains the areolar connective tissue and blood vessels that provide nourishment for growing hair Matrix ring of cells responsible for the growth of hairs and produce new hairs by cell division when older hairs are shed Hirsutism when women have an overproduction of andgrogen Sebaceous (oil) gland -secrete an oily substance called sebum -help keep hair from drying out -prevent excessive evaporation Blackheads enlarged sebaceous glands due to accumulation of sebum -propiani bacteria -color of blackheads is from melanin and oil, not dirt Arrector Pili -bundle of smooth muscle fibers -contract under stress, fright, cold, and emotions -forms goosebumps Sudoriferous Glands Eccrine glands Apocrine glands Eccrine Glands -most common -produces watery secretion -function throughout life -help regulate body temp Apocrine Glands -found mainly in skin of armpit, and pubic region -begin to function at puberty Ceruminous Glands -produces a waxy secretion in ear -provides a sticky barrier that prevents entrance of foreign bodies Mammary Glands produce breast milk Nails plates of tightly packed, keratinized cells Nail Body visible portion of nail Free Edge portion that extends past the end of the finger Nail Root portion of nail buried under fold of skin Lunula whitish area of skin (near cuticle) Nail matrix function is to bring about the growth of nails (1 mm/wk) Function of Nails help grasp and provides protection Phases of Deep Wound Healing 1. Inflammatory Phase 2. Migratory Phase 3. Proliferative Phase 4. Maturation Phase Inflammatory Phase 1. Blood clot forms in wound 2. White blood cells delivered to attack microbes Migratory Phase 1. Clot becomes a scab 2. Epitheleal cells migrate beneath the scab 3. Scar tissues built 4. Blood vessels regrow Proliferative Phase Epitheleal cells continue to grow beneath scab Maturation Phase 1. Scabs sloughs off once epidermis is restored 2. Collagen fibers organize (scar disappears) 3. Blood vessels return to normal Hypertrophic Scar remains within boundaries of original wounds Keloid Scar extends beyond boundaries of original wound Scar Tissue has fewer blood vessels and may not contain hair, skin glands, or sensory neurons Thermoregulation -temp. sensitive nerve endings in skin detect a change in skin temp -input is sent to brain (hypothalamus) which sends output to sweat glands -sweat more rapidly -brain sends output also to blood vessels so they dialate in dermis Skin and Aging -Age 40+ : collagen fibers decrease stiffen and break -Elastic fibers lose some elasticity -Hair and nails grow slower -Langerhans decrease (less immune) -Melanocytes stop function=grey hair Wrinkles skin form crevices