The Skin Integumentary System Chapter 4 Body

The Skin (Integumentary System) Chapter 4

Body Coverings: n Body coverings are responsible for: ¡ ¡ ¡ n covering surfaces lining body cavities forming protective layers. They are epithelial membranes and connective tissues.

Classification of Membranes

Epithelial Membranes n A. Epithelial Membranes - Include the skin, mucous membranes, and the linings of the heart, lungs, and abdomen 1) Cutaneous membranes – the superficial, outer covering of the skin (stratified squamous). This membrane is exposed to air and is dry.

Cutaneous Membrane

Epithelial Membranes 2) Mucous Membrane * These line the cavities that open to the outside body such as: respiratory, digestive, urinary, and reproductive systems. * They house stratified squamous or simple columnar. * They are wet membranes. * Some secrete mucous, others do not.

Mucous membrane

Epithelial Membranes 3) Serous Membrane * These body cavities are closed to the exterior. * They are never exposed but cling to internal membranes. * Serous fluid allows body organs to perform their functions without friction. A) peritoneum – abdominal cavity B) pleura - surrounds the lungs C) pericardium – surrounds the heart

Serous membrane

The Skin and Its Functions: FUNCTION PHYSIOLOGY 1) Protection Barrier/ receptors to pain/acidic secretions/ impermeable keratin 2) Heat loss or retention Sweat glands/ erector pilli “goose bumps” 3) Excretion Perspiration 4) Synthesizes Vitamin D Cholesterol/ Vitamin D/ Sunlight

Structure of Skin: n There are two kinds of tissue in the skin. ¡ ¡ n n The outer epidermis contains stratified squamous epithelium that becomes keratin (hard). The underlying dermis contains dense connective tissue. Friction cause the two layers of skin to separate, therefore, a blister forms. The subcutaneous tissue (adipose) anchors the skin to the underlying organs. This tissue is a shock absorber, insulator, and the “curvy shape” of a woman.

A closer look at each part of the skin… n Epidermis – There is no blood supply which allows you to rub or shave off the top layer without bleeding. ¡ ¡ ¡ Stratum germinativum – The only epidermal cells that receive nourishment through diffusion via the dermis. They reproduce rapidly. EX: new skin every two weeks. Stratum spinosum Stratum granulosum Stratum lucidum – flat and water repellant Stratum corneum – 20 -30 cell layers thick – all dead cells that rub or flake off easily

More about your skin… n n Your skin is totally new every 35 -45 days Melanin is the pigment cells that range in color from yellow to brown to black. ¡ ¡ ¡ Melanocytes are found in the stratum germinativum. When exposed to sunlight, the melanin pigment is triggered and tanning occurs. Freckles/Moles are concentrated melanin. Melanin is a natural protection against skin cancer *** 1 in 5 people will have some form of skin cancer*** People with herpes simplex II (cold sores) are more likely to have bouts with sun poisoning after sunburn. (“Valtrex”)

A closer look at each part of the skin… n Dermis – responsible for holding the body together “Your Hide” ¡ Papillary – The skin is uneven. The papillary provides nutrients to the epidermis and contains tiny nerve endings (Meissner’s corpuscles). This skin leaves definite patterns on the fingertips and feet. Your fingerprints are an example.

Meissner’s corpuscles

Dermis… cont. ¡ Reticular – A deep skin layer that contains blood vessels, sweat glands, oil glands, and deep pressure receptors. Collagen and elastic fibers give the dermis its toughness. The reticular layer stays well hydrated until we get older.

Dermis… cont. n n The dermis houses lots of blood vessels to maintain constant body temperature. Loss of normal blood supply can form ulcerations (see pg. 118). The dermis also has many nerve receptors in the skin (pressure, temperature, etc. )

Skin Color n Your skin color depends of 3 things: ¡ ¡ ¡ 1) The amount of melanin in the epidermis 2) The amount of carotene in the skin layers 3) The amount of oxygen bound to the hemoglobin

Skin Color n Be aware of changes in your skin color. This may signal certain disease states: ¡ ¡ Redness – “red” – high blood pressure Pallor (pale skin) – Anemia Jaundice (Yellow skin) – Hepatitus/ Cancer Black and blue marks – Cancer/Diabetes

Extensions of your skin n Glands, Hair follicles, and nails are extensions or appendages of the skin. These appendages let you know when you’re sick.

Cutaneous Glands n Release their secretions onto the skin’s surface. They release into the stratum germinativum but are embedded into the deep layers of the dermis. A) Sebaceous Glands (Oil) – The oil is released into the hair ducts everywhere except the palms of the hand the soles of the feet. They contain lubricants that keep the skin moist and deter bacteria.

Side note: Puberty n n Males – ages 14 -16, Females ages 1213 Puberty brings increased secretions which aggravates teenage acne. Whiteheads and blackheads can become so severe that scarring occurs.

Cutaneous Glands n B) Sweat Glands – There are two types of sweat glands ¡ Eccrine glands – made up of water, salts, urea, and vitamin C. Sweat is acidic with p. H of 4 -6. These glands regulate heat with a norm temp of 98. 6 o. F. n ¡ EX: Football player’s death – 108 o. F Apocrine glands – provide sweat to the axillary (armpit) and genital areas. These secretions may have a milky yellow color and contain fatty acids and proteins. When bacteria are present, they can have a foul odor.

Hair and hair follicles n n The body is covered in hair. The main function is protection: eyelashes, scalp hair, respiratory tract, etc. The hair is made up of epithelial tissue that is bendable.

Parts of the hair ¡ ¡ ¡ n n n 1) root – enclosed in a follicle. 2) shaft – the part that we wash, cut, and style 3) hair bulb - the inferior end of the follicle Your hair cells are dead and composed of protein Each hair has a medulla surrounded by a cortex that is covered by a cuticle. The cuticle is made up of keratin and continued friction causes split ends. Melanocytes make up your hair color.

Nails n n n Nails are extensions of the epithelial cells that contain a free edge, a body, and a root. The nail contains folds that are known as the cuticle. Nails are heavy keratin that are non-living. Nails are clear, but appear pink because of blood flow. Blue nail beds represent a low blood supply.

Homeostasis n Homeostasis (Balance) is necessary for the skin to carry out its functions. When homeostasis is lost, disorders can occur

Athlete’s Foot n n n Itchy, red, peeling of skin. This is an example of a fungus infection. “tinea pedis”

Boils n n Inflammation of the hair follicle or sebaceous gland “Staph Infection”

Cold Sores n n A side effect of Herpes simplex. The virus remains dormant until emotional upset, UV radiation, or fever. “Fever blisters”

Contact dermatitis n n Itching, redness, swelling of the skin followed by blistering Exposure of skin to chemicals such as poison ivy.

Impetigo n n n Pink, fluid filled, lesions that are yellow and crusty. They rupture and are highly contagious. Staphyloccus is common in elementary children.

Psoriasis n n Red epidermal lesions covered with dry, silvery scales. Trauma, infection, hormones, stress, etc. May be the cause.

BURNS n Burns are tissue damage caused by heat, electricity, UV radiation, or caustic chemicals.

Burns are serious because… n The body loses fluids containing proteins and electrolytes. Dehydration can result. The body organs begin to shut down so fluids must be replaced immediately. n RULE OF NINES – pg 108 - STUDY

Burns are serious because… n Infection is also serious because the immune system becomes weak. Burned skin is sterile for the 1 st 24 hours but bacteria shows up soon after. ¡ ¡ ¡ 1 st degree burns – damage to the epidermis that usually is uncomfortable for 2 -3 days EX: sunburn 2 nd degree burns – damage to the epidermis and the upper region of the dermis. The area is red, painful, and had blisters. 3 rd degree burns – damage to both the epidermis and dermis layers of skin. The burned areas have gray-white or black color. They destroy nerve endings so there is not pain. The skin can’t repair itself. Skin grafting must be done to replace scar tissue. Facial burns are more dangerous because of damaged respiratory airways.

1 st degree burns

2 nd degree burns

3 rd degree burns

Skin Cancer: Tumors of the Skin n n Benign – harmless and usually localized. EX: wart Malignant – cancerous and evades other body parts EX: melanoma

Major Causes of Skin Cancer: n n 1) overexposure to UV radiation in sunlight or tanning beds 2) Irritation of the skin by infections, chemicals, or physical trauma. (constant friction)

Types of Skin Cancer n Basal Cell Carcinoma ¡ ¡ ¡ Least malignant and most common form of skin cancer. They invade the dermis and subcutaneous layer but are not life threatening. 99% curable, and arises from Stratum germanativum.

Basal Cell Carcinoma

Types of Skin Cancer n Squamous Cell Carcinoma ¡ ¡ ¡ (stratum spinosum) A scaly red elevation (papule) They appear on the scalp, ears, back of hands, and lower lip. The sun also causes this type of carcinoma Common in Golfers and farmers

Squamous Cell Carcinoma

Types of Skin Cancer n Malignant melanoma ¡ ¡ 5% of skin cancers Usually occurs as a brown to black spreading patch that metastasizes to surrounding lymph and blood vessels

Malignant melanoma

ABCD Rule n Use the ABCD Rule ¡ ¡ Asymmetry – the two sides of the mole don’t match Border Irregularity – the border of the lesion are not smooth but have indentations Color – different colors (blacks, blues, reds, tans, etc) Diameters – the spot is larger than 6 mm (pencil eraser)

Development n n Fetal Skin- Is hairy (5 – 6 months) called lanugo. Vernix caseosa covers the babies skin to protect it while its inside the mother. Newborn’s skin is thin…adolescent’s skin is oily…ideal skin in 20’s and 30’s…afterwards skin starts to degrade…elderly skin is thin and bruises easily, loss of adipose (sensitive to cold). Hair follicles also degenerate

Fetal Lanugo