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ANAPHY SUMMARIES FROM PEARSON...

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ANAPHY 2nd Quarter Chapter 4 Skin and Body Membranes Body Membranes Functions: 1. Cover body surfaces 2. Line body cavities 3. Form protective sheets around organs  Classified according to tissue types Epithelial Membranes: 1. Cutaneous membranes 2. Mucous membranes 3. Serous membranes Connective tissue membrane: 1. Synovial membranes Epithelial Membranes  Simple organs  Called covering and lining membranes  Contain: - Epithelial tissue layer - Connective tissue layer 1.   

Cutaneous membrane =skin Dry membrane Outermost protective boundary Construction Epidermis- composed of keratinized stratified squamous epithelium Dermis- mostly dense fibrous connective tissue

2. Mucous Membrane(mucosae)  Moist membrane, continuously bathed in secretions  Not all mucosae secretes mucus  Line all body cavities that open to the exterior surface such as:  Hollow organs of the respiratory , digestive, urinary and reproductive duct  Adapted for absorption or secretion  Mucosae of respiratory and digestive tract secretes large amount of protective, lubricating mucus, but the urinary tract does not.  Mostly contained stratified squamous epithelium(mouth or esophagus) or Stratified Columnar Epithelium (digestive tract)  Construction Epithelium type depends on site Loose connective tissue (lamina propria) 3. Serous Membranes (serosae)  Line open body cavities that are closed to the exterior of the body  Occur in pairs, separated by serous fluid with a visceral and parietal layer  Parietal layer lines a specific portion of the wall of the ventral body cavity  visceral layers, which covers the outside of the organs in that cavity  Serous layers are separated by a scanty amount of thin clear fluid called

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Serous fluid allows the organs to slide easily across the cavity walls and one another without friction  Construction Simple Squamous Epithelium Areolar Connective tissue Specific Serous Membranes  Peritoneum- Abdominal cavity  Pleura- Around the lungs  Pericardium- around the heart Connective Tissue Membranes 1. Synovial membrane  Loose areolar tissue only  Line fibrous surrounding joints  Line bursae  Line tendon sheaths  Secrete lubricating fluid to cushion organs moving against the muscle activity Integumentary System  Skin(cutaneous membrane)  Skin appendages (Sweat glands, Oil glands, Hair and nails) Function: 1. Insulates and cushion deeper body organs 2. Protects the entire body from: - Mechanical damage (bumps and cuts) - Chemical damage (acids and bases) - Thermal damage(heat or cold) - UV radiation (sunlight) - Microbes - Desiccation 3. Aids in loss or retention of body heat as controlled by the nervous system 4. Aids in excretion of urea and uric acid 5. Synthesizes Vitamin D Structure of the Skin  Epidermis  Dermis Hypodermis(subcutaneous layer)  Anchors the skin to underlying organs  Not technically part of the integumentary system  Composed mostly of adipose tissue  Serve as a shock absorber and insulates deeper tissues Epidermis (outer layer)  Capable of being hard and tough  Stratified squamous epithelium  Keratinocytes(most common cell), produces a fibrous protein called keratin  Avascular  Composed of 5 layers strata

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serous fluid Serous fluid secreted by both membranes, potential space between two membranes

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Layers from deepest to superficial: 1. Stratum basale 2. Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum(thick, hairless skin) 5. Stratum corneum Stratum Basale (stratum germinativum)  Deepest layer of epidermis  Lies next to dermis  Wavy borderline with the dermis anchors the two together  Cells undergoing mitosis  Daughter cells are pushed upward to become the more superficial layer  Contains epidermal stem cells,melanocytes and Merkel cells Stratum Spinosum  Cells become increasingly flatter and more keratinized Stratum granulosum  Flattened cells  Deteriorating  Keratin granules Stratum lucidum  Formed from dead cells of deeper strata  Occurs only in thick hairless skin of the palm and soles  Transparent  Lysis Stratum Corneum  Outermost layer of epidermis  Dead cells are filled with keratin  For water resistant  Presence of glycolipid

Melanin  Pigment produced by melanocytes  Melanocytes- lies in the stratum basale of the epidermis  Color: yellow to brown to black  Accumulates in membrane bound granules called melanosomes  Melanosomes- amount of melanin produced depends upon generics and exposure to sunlight  Freckles and moles are seen where melanin is concentrated in one spot Epidermal dendritic cells

Merkel cells  Associated with sensory nerve endings  Serve as touch receptors called Merkel discs Dermis  Connective tissue  Underlies the epidermis layers of dermis: 1. Papillary layer (upper dermal region  Contain projections called dermal papillae  Indent the epidermis above  Many projections contain capillary loops and others house pain and touch receptors  On palm and sole surfaces, papillae increase friction and gripping ability  Fingerprints are identifying films of sweat 2. Reticular layer (deepest skin layer)  Blood vessels  Swear and oil glands  Deep pressure receptors(lamella corpuscles) Other dermal features o Cutaneous sensory receptors-alert o Phagocytes- prevent microbes o Collagen and elastic fibers- found throughout the dermis o Blood vessels – maintaining homeostasis Skin color Pigments:  Melanin - Yellow, reddish brown, black pigments - Pigment is melanocytes , Found in melanosomes  Carolene - Orange yellow pigment from some vegetables - Carotinemia- excess intake of carrots/yellow veg.  Hemoglobin - Red coloring from blood cells in dermal capillaries - Oxygen content determines the extent of red coloring - Found in red blood cells  Redness(erythema)– due to embarassment, inflammation,hypertension,fever, allergy  Pallor (blanching)- due to emotional stress, fear,anemia,lbp, impaired blood flow  Jaundice (yellow cast)- liver disorder  Bruises – hematoma Appendages of the Skin Cutaneous glands are all exocrine glands o Sebaceous glands o Sweat glands o Hair o Hair follicles o Nails Sebaceous glands (oil)  Located all over the skin except palms

 Alert and activate immune cells to a threat( bacterial or viral invasion)

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Produce sebum Makes skin soft and moist Prevents hair brittleness Kill bacteria...