Skin and Body Membranes

 These are membranes that cover and line the body (any area that is exposed to air).  These include: cutaneous membranes (skin), mucous membranes, and serous membranes.

MUCOUS MEMBRANES SEROUS MEMBRANES  Line all body cavities exposed to the exterior (respiratory, urinary, and reproductive tracts).  These act as protection and lubrication (mostly).  Line enclosed body cavities:  Parietal lines the wall  Visceral lines the organs  Serous fluid is between the serous membranes (visceral and parietal)  The peritoneum lines the organs of the abdominal cavity.  The pericardium surrounds the heart and pleura surrounds the lungs.

 Synovial membranes: surround the joints and contain lubricating fluid (synovial fluid)  May contain sacs called bursae

 a.k.a. skin  Means covering  Contains keratin, a protein  Serves for homeostasis:  Protects the body (covers)  Regulates body temperature  Prevents H 2 O loss  Secretes some waste  Location of sensory (some) equipment

1. Epidermis: -outer layer of skin -contain melanocytes (cells that have melanin, a pigment) 2. Dermis: -inner layer of skin -composed of connective tissue (with collagen & elastic fibers), nervous tissue, & blood -thicker than epidermis 3. Subcutaneous: -a.k.a. as the hypodermis -Below the dermis -Composed of loose connective tissue and adipose (fat) -Binds the skin to underlying organs

 Think about the saying “Beauty is only skin deep.” Everything we see when we look at someone is dead skin cells.  The average person sheds about 40 lbs of dandruff (part of the epidermis) in a lifetime.  We grow a new epidermis about every days.

 Fingerprints, caused by dermal papillae (or nipples), are genetically determined.  Since the dermal layer contains fat (adipose), and as we age, we lose fat and the elasticity of our skin, the dermal layer sags. This forms wrinkles.

PIGMENTS THAT CAUSE SKIN COLOR:OTHER CAUSES OF SKIN COLOR:  Melanin (yellow, reddish- brown, or black)  Carotene (orange-yellow)  Hemoglobin (red)  Emotions  Illness (hypertension, fever, inflammation, etc.)  Jaundice (yellow skin)  Bruising  Environment (UV rays)  Bloods vessels: If poorly oxygenated, a bluish appearance occurs. This is called cyanosis.

Cutaneous glands: a.k.a. exocrine glands  Sebaceous glands (oil secreting glands)  Secrete sebum (oil)  Keeps hair and skin soft  Protects skin and kills bacteria  Sweat glands  a.k.a. Sudoriferous glands  Eccrine glands secrete sweat to regulate temperate  Apocrine glands secrete sweat in emotions (stress, pain, sex, and sometimes thermoregulation).  Sweat is a mixture of water, urea, and salts.

 Hair protects skin  Hair follicles produce hair  Located on all parts of skin except: palms, soles, lips, nipples, and some reproductive structures.  Nails protect skin and sensory equipment under skin.

Warning: there are images on the next few slides that MAY be disturbing! Really.

 Bedsores (pressure ulcers) occur when a patient remains in one position too long. The skin cells dies as a result of lack of blood supply.

 Acne is caused by an infection of the sebaceous glands.

 A burn is tissue damage (& cell death) caused by some type of intense heat.  There are 2 life- threatening problems for burn-victims: fluid loss and infection  Pathogens (invaders like bacteria or fungi) feed off of destroyed skin.  Doctors estimate fluid loss (for burn victims) by using the rule of nines.  This divides the body into 11 areas, each accounting for 9% of the total body surface area + 1% representing the genital area.

 First-degree burns: epidermis is damaged (think sunburns).  Second-degree burns: epidermis and some dermal tissue (upper layer) are damaged.  Blisters occur.  This is painful.  Third-degree burns: destroys skin (a.k.a. full- thickness burns).  Nerve endings in the area of burned tissue are destroyed (therefore, NOT painful).  Skin grafting must be done to recover b/c skin will not regenerate in these areas.

SQUAMOUS CELL CARCINOMA:BASAL CELL CARCINOMA:  Quick growing skin cancer that appears on epidermis.  Can metastasize (spread) to lymph nodes (w/o treatment: surgery or radiation).  Usually caused by sun exposure.  Often found on ears, scalp, lower lip, & back of the hand  Most common type of skin cancer.  Slow growing, shiny round nodules appear.  Usually caused by sun exposure.  Rarely spread before treatment (surgery).  Often found on face.

Malignant melanoma:  Cancer of melanocytes  Can be lethal  Usually appear spontaneously (however, can be caused b/c a mole changes, DNA is damaged, genetic causes, or sun damage).  Metastasizes quickly to lymph nodes and BVs (then to other organs).  Treatment: surgery, radiation, and/or chemotherapy

ABCD recognition:  (A) Asymmetry: pigment is uneven  (B) Border irregularity: the lesion is not smooth  (C) Color: the color of the lesion varies within the lesion (shades)  (D) Diameter: the lesion is larger than 6 mm (pencil eraser)

Look up in text or online! Know the following: Athlete’s foot, boils, cold sores, dermatitis, impetigo, and psoriasis.

 This slide show was developed by Dana Halloran,  Cardinal Mooney High School, Sarasota, FL.  Used with her personal permission,  adapted and amended by Rosa Whiting,  Manatee School for the Arts, Palmetto, FL.