Integumentary System PDF

Membranes 1. Mucous membranes - loose connective tissues. - binds organs together, holds tissue fluid. - line passageway such as the nasal and oral cavities, and tubes of the respiration, 2. Serous membrane - secrete watery substance, whic...

Membranes 1. Mucous membranes - loose connective tissues. - binds organs together, holds tissue fluid. - line passageway such as the nasal and oral cavities, and tubes of the respiration, 2. Serous membrane - secrete watery substance, which lubricates membrane surfaces to prevent friction that can damage two organs. 3. Synovial membranes - loose connective and adipose tissue. - They line the cavities of joints such as the knee and elbow. - Contains Synovial fluid,which is thick liquid with the consistency of an egg white that helps reduce friction b/n 2 bones INTEGUMENTARY SYSTEM (cutaneous/integument/skin) - The integumentary system includes the skin and accessory structures, such as hair, glands, and nails. - Largest organ of the body - Waterproof, stretchable - Self-repairs - 15-20% of body weight EPIDERMIS Stratified squamous epithelium Outer layer Contains 4 types of cells: 1. KERATINOCYTES :produce KERATIN and LAMELLAR GRANULES 2. MELANOCYTES :Pigment producing cells MELANIN: contributes to skin color EUMELANIN : BROWN-BLACK most common PHEOMELANIN : RED-BROWN 3. LANGERHANS CELL /dendritic cells 4. MERKEL CELL /tactile epithelial cells-least numerous  LAYER OF THE EPIDERMIS 1.Stratum basale - Deepest layer - consists of cuboidal or columnar cells that undergo mitotic divisions about every 19 days. 2.Stratum spinosum - take on a flattened appearance and accumulate lipid-filled vesicles called lamellar bodies - dendritic cells and projections of melanocytes are also present in the stratum spinosum. 3.Stratum granulosum - consists of three to five layers of flattened kerat inocytes that are undergoing apoptosis. 4.Stratum lucidum - present only in the thick skin of areas such as the palms, palmar surfaces of the digits, soles, and plantar surfaces of the toes 5.Stratum corneum - Flat keratinized layer of dead cells DERMIS - the deeper part of the skin - has the ability to stretch and recoil easily - composed of dense collagenous connective tissue containing fibroblasts, adipocytes, and macrophages. Nerves, hair follicles, smooth muscles, glands, and lymphatic vessels extend into the dermis PAPILLARY DERMIS - superficial portion of dermis 1/5 RETICULAR DERMIS - deeper portion of dermis 4/5 (extra) PAPILLAE : - tiny raised protrusions on the tongue that contain taste buds. HYPODERMIS / SUBCUTANEOUS TISSUE - Storage depot for fats - Attaches the skin into underlying tissues and organs  Cutaneous Sensory Receptors: 1) Meissner’s corpuscle (Epidermis) - Corpuscle of touch.Detect light motion against the skin. 2) Free nerve endings (Dermis) - Detects changes in temperature. - Respond to tissue trauma. - Pain receptor 3) Root hair plexuses (Dermis) - Detect movements of hair. 4) Lamelated (Pacinian corpuscles) - Detect deep pressure and high frequency vibration. 5) Ruffini corpuscles - Detect deep pressure and stretch. 6) Meissner's corpuscles - Detect light pressure, low frequency vibration. Parts of Subcutaneous tissue: 1) Areolar connective tissue - Connects skin to muscle. - Contains WBC to destroy pathogen - Contains mast cells that release histamine, leukotriens and other chemicals involved in inflammation- a protective reaction of living tissue or injury. 2) Adipose tissue - Contains stored energy in the form of fats. - Cushions bony prominences. - Contributes to appetite( adipose tissue is involves in the cessation of eating. - Contributes to use of insulin. - Produces cytokines that activate WBC.  SKIN PIGMENTATION MELANIN : produced by melanocytes in the stratum basale :blocks damage from ultraviolet (UV) rays 1. EUMELANIN : (brown-black, most common) 2. PHEOMELANIN :(red-brown) HEMOGLOBIN a red pigment in red blood cells CAROTENE a yellow-orange pigment stored in the stratum corneum and adipose tissue CYANOTIC blood is not picking up enough oxygen BLUISH JAUNDICE build up of yellow pigment ( Bilirubin )in skin *liver disease GLANDS OF SKIN 1. Sudoriferous (sweat) glands Types: A. Eccrine - small sweat gland and distributed over nearly the entire body; most especially numerous on the forehead, upper lip,palms and soles. - It secretes sweats by perspiration B. Apocrine (odiferous gland) - Found in the armpits, dark region around the nipples, the outer lips of the vulva and the anal and genital regions. - Only start to become active at puberty. - This is responsible for body odor. ***emotional sweating/cold sweats 2. Sebaceous gland (oil gland) - They are found in the dermis with the functions of lubrication and protection. - Produce SEBUM : - a lipid substance commonly reffered to as oil. this functions as an emollient (skin softening agent) and protective against bacteria and fungi. 3) Ceruminous gland- located in the dermis of the ear canals. - Secretes CERUMEN (ear wax) – keeps the outer surface of the ear pliable and prevents drying.  Hair - Composed of dead, keratinized epidermal cells - Genetic and hormonal influences determine the thickness and distribution of our hair 3 kinds of human hair: 1)Lanugo - fine, silky fetal hair that appears during the last trimester of pregnancy - probably has something to do with the maturation of hair follicles. 2) Angora hair - Continously growing as in the scalp, face of sexually mature males. 3) Definitive hai - Grows to certain length then stops growing. Example: Eyelashes, eyebrows, pubic hair, axillary hair.  NAILS plates of tightly packed, hard, dead, keratinized epi dermal cells that form a clear, solid covering over the dorsal surfaces of the distal portions of the digits. STRUCTURE : NAIL PLATE: - the visible portion of the nail.its flattened, keratinized cells fill with a harder type of keratin and the cells are not shed FREE EDGE: - is the part of the nail plate that may extend past the distal end of the digit NAIL ROOT: - is the portion of the nail that is buried in a fold of skin. LUNULE : - “little moon” :whitish, crescent- shaped area of the proximal end of the nail plate EPONYCHIUM / CUTICLE - a narrow band of epidermis that extends from and adheres to the margin (lateral border) of the nail wall BURNS A burn is tissue damage caused by excessive heat, electricity, radioactivity, or corrosive chemicals that denature (break down) the proteins in the skin cells. Burns are graded according to their severity Lund-Browner method- This method assigns percentage of surface area to certain parts of the body  SOME COMMON SKIN DISORDERS: 1) Acne - Most common in adolescent; increased hormonal activities. - It affects more commonly on young males. 2) Bedsores - produced in bony, unprotected areas where skin is close to a bone and undergoes constant pressure. - Typical problem areas are the hips, elbows, tailbone, knees, and heels, ankles and shoulder blades. - First signs are warm reddened spots on the skin----- purplish - Breaks in the skin may follow; bacterial infection is common if left untreated. 3) Psoriasis - Condition marked by lesions that are red. Dry and elevated and are covered with silvery, scaly patches. - Usual sites are the elbows, knees, scalp, face, and lower back. 4) Cellulitis - Spreading infection caused by some anaerobic microbes or by streptococcus perfringens. - If untreated, the products of inflammation may enter the blood causing septicemia SUPERFICIAL INFECTIONS OF THE SKIN CAUSED BY FUNGI 5) Ringworm - an outward spreading of inflammation. 6) Tinea Pedis - (athlete’s foot) affects the area between the toes. —Both infections are spread by direct contact.