Anatomy Chapter 4 Skin and Body Membranes PDF

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Skin and Body Membranes 2 major categories of body membrane: 1. Epithelial Membranes - covering and lining membranes 2. Cutaneous Membrane - is the skin; its superficial epidermis is composed of keratinizing stratified squamous epithelium; dry membrane Mucous Membrane (mucosa) - resting on a loose connective tissue membrane called lamina propria ~ Most mucosae contain either stratified squamous epithelium (as in the mouth and esophagus) or simple columnar epithelium(as in the rest of the digestive tract). Serous Membrane (serosa) - resting on thin layer of aerolar connective tissue - occurs in pairs: parietal layer lines & visceral layer Serous Fluid - a scanty amount of thin, clear fluid that separates the serous layers Peritoneum - is the serosa lining the abdominal cavity and covering its organs Pleura - a membrane surrounding the lungs Pericardium - a membrane surrounding the heart Synovial Membrane - composed of soft areolar connective tissue and contains no epithelial cells; line the fibrous capsule surrounding joint; line small sacs of connective tissue called bursae and tube like tendon sheaths Carpal Tunnel Syndrome - tingling sensation due to injury of tendon

Functions of Integumentary System Functions (protects deeper tissue from) Mechanical Damage (bumps)

Chemical Damage (acids and bases)

Bacterial Damage

Ultraviolet radiation (damaging effects of sunlight) Thermal Damage (heat or cold) Desiccation (drying out) Aids in heat loss or heat retention (controlled by the nervous system)

Aids in excretion of urea and uric acid Synthesizes Vitamin D

How Accomplished Physical barrier contains keratin, which toughens cells; fat cells to cushion blows; and pressure receptors, which alert the nervous system to possible damage Has relatively impermeable keratinized cells; contains pain receptors, which alert the nervous system to possible damage Has unbroken surface and 'acid mantle' (skin secretions are acidic, and thus inhibit bacteria). Phagocytes ingest foreign substances and pathogens, preventing them from penetrating into deeper body tissue Melanin produced by melanocytes offers protection from UV damage Contains heat/cold receptors Contains a waterproofing glycolipid and keratin Heat loss: By activating sweat glands and by allowing blood to flush into skin capillary beds so that heat can radiate from the skin surface Heat Retention: By not allowing blood to flush into skin capillary beds Contained in perspiration produced by seat glands Modified cholesterol molecules in skin converted to Vitamin D by sunlight

Function: *protective *insulates *cushions ~ The uppermost layer of the skin is full of keratin and is cornified , or hardened to help prevent water loss from body surface ~ Epidermis - capable of keratinizing or becoming hard and tough - composed of up to 5 layers or strata: from the inside are the stratum basale, spinosum, granulosum, lucidum, and corneum - Avascular –it has no blood supply on its own by diffusion supply nurients Dermis – is made up of dense connective tissue Subcutaneous tissue (hypodermis) - deep to the dermis and essentially is adipose tissue; shock absorber and insulates ~ Most cells of the epidermis are keratinocytes, which produce keratin(protein), the fibrous protein that makes the epidermis a tough protective ~ Stratum Basale (Stratum Germinativum) - deepest cell layer of epidermis; are cells that constantly undergoing cell division and millions of new cells produced daily ~ Stratum Spinosum & Stratum Granulosum becomes flatter and increasingly full of keratin and finally they die forming the clear stratum lucidum-(on the palms and soles of feet) without hair

Stratum Corneum - the outermost and superficial layer and is 20 to 30 cell layers thick; rubs and flakes off slowly and steadily as the dandruff familiar to everyone. Melanin –(protection) a pigment that ranges in color from yellow to brown to black Melanocytes - a special spider-shaped cell that produces melanin and is found in the stratum basale; manufacture inner most layer ~Freckles and moles are seen where melanin concentrated Herpes simplex (cold sore) - virus due to overexposure to sun and causes elastic fibers to clump Type 1 - mouth Type 2 - genital ~ The dense (fibrous) connective tissue making up the dermis(hide) consists of two major regions-the papillary and reticular areas ~ Papillary Layer – fingerprint; upper dermal region; uneven and has peglike projections from its superior surface called dermal papillae Dermal Papillae - responsible for fingerprint, and contains capillary loops Meisner’s corpuscle –touch receptor; other house pain receptor (free nerve endings) Reticular Layer - deepest skin layer that contains blood vessel, sweat, and oil glands and deep pressure receptors called Pacinian corpuscles ~ Both collagen and elastic fibers are found throughout the dermis ~ Collagen fibers – responsible for the toughness of the dermis; also attract and bind water and thus help to keep the skin hydrated Elastic fibers – give the skin is elasticity when we are young Decubitus ulcers (bedsore) - occur in bedridden patients who are not turned regularly or who are dragged or pulled across the bed repeatedly Three pigments contribute to skin color: 1. Amount and kind of (yellow, reddish brown, or black) of melanin in the epidermis 2. The amount of carotene deposited in the stratum corneum and the subcutaneous tissue 3. The amount of oxygen-rich hemoglobin (pigment in red blood cells) in the dermal blood vessel. Cyanosis – blue condition; common during heart failure and severe breathing disorders. Skin color signals: 1. Redness or erythema - embarrassment, fever, hypertension, inflammation, allergy 2. Palor or blanching - stress, anemia, low blood pressure, impaired blood flow into the area 3. Jaundice (yellow cast) - abnormal yellow of skin usually signifies liver disorder 4. Bruises or black-and-blue marks - sites where blood has escaped from the circulation and has clotted in the tissue spaces (such clotted blood masses are called hematoma) 4 Cardinal signs of Inflammation: heat - color swelling - tumor

pain- dolor

redness - rubor

Cutaneous gland - all exocrine glands that release secretion to the skin surface via ducts; They fall into 2 groups: Sebaceous gland and sweat gland Sebaceous Gland (Oil glands) - that are found all over the skin except the palms and soles of feet; produce sebum Whitehead - produced when sebaceous gland duct is blocked by sebum Blackhead - produced when sebaceous gland duct is blocked by sebum then oxidizes and dries, it darkens Acne - active infection of the sebaceous gland accompanied by pimples on the skin Seborrhea - fast forming or fast flowing sebum Eccrine Glands - found all over the body; produce sweat (it should be acidic to kill bacteria) Apocrine Glands – odorless; confined at the axillary and the genitals area Matrix - growth zone Cuticle - most heavily keratinized region; provides strength and helps keep the inner hair layers tightly compact Melanocytes - makes hair pigment ~ When the hair shaft is oval, hair is smooth and silky and the person has wavy hair. ~ When the shaft is flat and ribbonlike, the hair is curly or kinky. If it is perfectly round, the hair is straight and tends to be coarse. Arrector Pili- small bands of smooth muscle cell connect each side of the hair follicle to the dermal tissue Nail - scalelike modification of the epidermis that corresponds to the hoof or the claw of other animals; free edge a body and a root Nailfolds - borders that overlapped by the skin folds Cuticle- thick proximal nail fold Nail bed – stratum basale of the epidermis extends beneath the nail Nail matrix -responsible for nail growth Lunula - white cresent Infections and allergies: Athlete's Foot (tinea pedis) - itchy, red, peeling condition of the skin between the toes resulting fungus infection Boils and carbuncles - inflammation of hair follicles and sebaceous glands, common on the dorsal neck; Cold sores (fever blisters) - small fluid-filled blisters that itch and stings, caused by herpes simplex infection; occur around the lips and in oral mucosa of the mouth

Contact Dermatitis - exposure of skin to chemicals resulting in itching, redness, swelling and blistering Impetigo - cause by a highly staphylococcus infection resulting to pink, water-filled, raised lesions that develop a yellow crust and eventually rupture. Psoriasis - overproduction of skin cells; disfiguring; autoimmune disorder in which the immune system disorder in which the immune system attack a person own tissue Burn - tissue damage and cell death caused by heat, electricity, UV radiation or certain chemicals Rule of nines - a method that divides the body into 11 areas, each accounting 9 percent of the total body surface area 1st Degree burn - only epidermis is damaged where the area becomes red or swollen; heal 2-3 days without special attention ;sunburn 2nd Degree burn - includes epidermis and the upper region of the dermis where the skin is red and painful and blisters appear 1st and 2nd refer to partial-thickness burns 3rd Degree burn - destroys the entire thickness of the skin and is also called full-thickness burns 4th Degree burn - destroys up to the muscles or bones Eschar - rubbery part of the burned area Skin Cancer - the single most common type of cancer in humans; factor is overexposure to ultraviolet radiation in sunlight Basal cell carcinoma- least malignant and common of skin cancer; the cancer lesions occur most often on exposed area of the face and appear as shiny dome-shaped nodules that later develop a central ulcer with a “pearly” beaded egde Squamous Cell carcinoma- arises from the stratum spinosum; lesion appear as a scaly, reddened papule that gradually forms a shallow ulcer with a firm raised a border. Malignant Melanoma- is a cancer of melanocytes; pigment develop from pigmented moles Wart (kalonggo)- caused by a virus Lanugo -fine downy hair in a newborn baby Vernix Caseosa - white cheesy look in a newborn baby; produce by sebaceous glands Milia- are accumulation in the sebaceous glands appear as small white spots on the baby’s nose and forehead Alopecia - baldness Vellus -colorless and very tiny hairs...