Integumentary System Latest Version 100% Pass

Integumentary System Latest Version 100% Pass Integumentary System: Location ~ Skin ~ Hair ~ Nails ~ Sweat Glands ~ Sebaceous Glands Skin: Characteristics Epidermis - most superficial ~ mostly stratified squamous epithelium (keratinized) ~ avascular Epidermis cell characteristics ~ Keratinocytes ~ tightly connected by desmosomes ~ lose millions every day (slough off) Keratinocytes an epidermal cell that produces keratin, the fibrous protein that helps give the epidermis its protective properties desmosomes fasten cells together into strong sheets Melanocytes spider shaped, deep in the epidermis; produce melanin (packaged into melanosomes) ~ Melanosomes transferred to keratinocytes (protect nucleus from UV damage) Melanosomes Pigment carrying granules that produce melanin, a complex protein. Dendritic Cells ~ star-shaped cells with functions similar to macrophages; ~ activators of immune system; ~ arise from bone marrow and migrate to the epidermis Tactile Cells (Merkel cells) sensory touch receptors Layers of the Epidermis (Palms and Soles have 5) ~ Stratum Corneum ~ Stratum Lucidum (only thick skin) ~ Stratum Granulosum ~ Stratum Spinosum ~ Stratum Basale Stratum Basale aka Stratum Germinativum ~ Base layer ~ Consists of a single row of stem cells that actively divide ~ One cell moves toward surface (25-45 days) - dies near surface ~ Other daughter cells stay in layer as stem cells ~ Melanocytes also found here Stratum Spinosum ~ Several cell layers thick ~ Perkeratin filaments & intermediate filaments ~ Keratinocytes look spikey-prickle cells ~ Melanosomes & Dendritic cells Stratum Granulosum ~ Flattened cells (4-6 layers thick) ~ Nuclei and organelles disintegrate ~ dead cells above this layer Apoptosis process of programmed cell death Stratum Lucidum a layer of the epidermis found only in the thick skin of the fingers, palms, and soles Stratum Corneum outermost layer of the epidermis, which consists of flattened, keratinized cells; ~ dead cells slough off as dandruff & dander ~ humans can shed 50,000 cells per minute Dermis Layers Papillary Layer Reticular Layer Papillary Layer: Characteristics ~ Superficial layer ~ Aeolar CT consisting of loose interlacing collagen & elastic fibers & blood vessels ~ Loose fibers allow phagocytes to patrol for micro organisms ~ Dermal papillae: Dermal papillae ~ superficial region of dermis that sends fingerlike projections up into epidermis ~ Projections contains capillary loops, free nerve endings, and touch receptors (tactile corpuscles, also called Meissner's corpuscles) phagocytes White blood cells that attack invading pathogens Reticular Layer ~ Deep layer; ~ Dense Irregular CT ~ Cleavage (tension) lines ~ Externally invisible ~ Important to surgeons because incisions parallel to cleavage lines heal more readily ~ Flexure lines Cleavage (tension) lines in reticular layer are caused by many collagen fibers running parallel to skin surface Flexure lines ~ lines of reticular layer are dermal folds at or near joints ~ Dermis is tightly secured to deeper structures ~ Skin's inability to slide easily for joint movement causes deep creases ~ Visible on hands, wrists, fingers, soles, toes Striae "Stretch marks" Extreme stretching of skin can cause dermal tears, leaving silvery white scars Blisters Acute, short-term traumas to skin, fluid-filled pockets that separate epidermal and dermal layers Melanin The dark pigment synthesized by melanocytes and packaged into melanosomes; ~ Sent to keratinocytes to shield DNA from sunlight ~ Freckles - accumulations of melanin ~ responsible for skin color Carotene a yellow to orange pigment that accumulates in stratum corneum & hypodermis ~ palms and soles most obvious ~ accumulates when large amounts of carotene-rich foods are eaten Cyanosis bluish coloration of the skin Causes: a deficient amount of oxygen in the blood; low oxygenation of hemoglobin Erythema redness of the skin caused by swelling of the capillaries; Causes: Fever, hypertension, inflammation, allergies Pallor blanching or pale color; Causes: Anemia, decreased blood pressure, fear, anger Jaundice yellow cast; associated with liver dissorders A yellowing of the skin and eyes Bronzing color cast; Causes: inadequate steroid hormones; Ex. Addison's Disease Bruises black & blue coloring; clots clotted blood beneath skin; hematomas Hair: Characteristics ~ Dead, keratinized cells ~ Warning of insects on skin, protection from physical trauma (head), shield from sun ~ none on palms, soles, lips, nipples, portions external genitalia Hairs aka Pili: Characteristics ~ Produced by hair follicles ~ Hard keratin - doesn't flake off ~ Shaft above scalp. Keratinization complete ~ Root - area within scalp, where keratinization still going on Arrector Pili Muscle Smooth muscle attached to the hair follicle that can cause goose bumps Hirsutism excessive hairiness; resulting from ovarian or adrenal tumors; Produce abnormally large amounts or androgens Alopecia thinning hair; baldness Sweat glands aka Sudoriferous glands ~ Contract with nervous system stimulation to force sweat into ducts. Sweat 99% water, salts, vitamin C, antibodies, microbe killing peptides, metabolic wastes Eccrine Sweat Glands Palms, soles, forehead ~ Contract with nervous sytem stimulation to force sweat into ducts Apocrine Sweat Glands Axillary & Anogenital regions ~More viscous sweat ~ Fatty substances & proteins ~ Larger than Eccrine ~ Begin functioning at puberty Ceruminous Glands Lining of external ear canal ~ Secrete cerumen Sebaceous Glands Oil glands ~ not on palms & soles ~ most develop from and secrete into hair follicle ~ secrete sebum Issues associated with Sebaceous Glands ~ Acne ~ Seborrhea Acne infectious inflammation of sebaceous glands Seborrhea yellowish/brownish lesions that flake off in infants; cradle cap Types of Skin Cancer ~ Basal Cell Carcinoma ~ Squamous Cell Carcinoma ~ Melanoma Basal Cell Carcinoma most common form of skin cancer; usually cured with excision Squamous Cell Carcinoma 2nd most common form of skin cancer; Stratum spinosum; May metastasize Melanoma Cancer of melanocytes; Highly metastic ABCD's of Melanoma A - Asymmetry B - Border. Irregulary C - Color. Several colors D - Diameter. >6 mm (size of pencil eraser) Burns Protein denatured. Immediate threat - dehydration!!! ~ And electrolyte balance Rule of nines estimates fluid loss - broken into 11 sections each 9% except genitals 1% Burns - Rule of Nines Degree of Burns - 1st Degree Epidermis only ~ redness, edema, pain Degree of Burns - 2nd Degree Epidermis & upper Dermis ~ blisters Degree of Burns - 3rd Degree Entire Thickness color: Gray-white, Cherry red, Black ~ Critical- >25% body second degree OR >10% third degree OR face, hands, feet with 3rd degree Burn Treatment ~ Debridement ~ Antibiotics ~ Grafting ~ Covering