The Integumentary System - guided notes

Transcription

1 The Integumentary System - guided notes Integument is skin. Skin and its make up the integumentary system. A fatty layer ( ) lies deep to it Two distinct regions. Epidermis and the Functions of skin 1. Cushions and insulates and is Screens UV Protects from chemicals, heat, cold, bacteria 2. vitamin D with UV 3. Regulates 4. Prevents unnecessary water loss 5. Sensory reception (nerve endings) Epidermis Keratinized stratified squamous epithelium to cells thick about as thick as a page. Four types of cells Keratinocytes deepest, produce keratin (tough fibrous ) - make dark skin pigment melanin Merkel cells associated with nerve endings Langerhans cells macrophage-like dendritic cells Layers (from deep to superficial) Stratum basale or germinativum single row of cells attached to dermis; youngest Stratum spinosum spinyness is artifactual; tonofilaments (bundles of protein) resist tension Stratum granulosum layers of flattened keratinocytes producing keratin ( and made of it also) Stratum lucidum (only on and ) Stratum corneum horny layer (cells dead, layers thick)

2 Four basic types of tissue 1. epidermis just discussed 2. dermis 3. tissue 4. tissue Dermis Strong, connective tissue: your hide Cells: fibroblasts, macrophages, mast cells, WBCs Fiber types: collagen,, reticular Rich supply of and Critical role in regulation (the vessels) Two layers (see next slides) areolar connective tissue; includes dermal papillae Reticular reticulum (network) of collagen and reticular fibers Fingerprints, palm prints, footprints The is the receptive site for the pigment of tattoos Hypodermis (Gk) = below the skin Subcutaneous ( ) = below the skin Also called superficial fascia fascia (Latin) =band; in anatomy: sheet of connective tissue Fatty tissue which stores fat and skin (areolar tissue and adipose cells) Different patterns of accumulation (male/female) Skin color Three skin pigments 1.Melanin: the most 2. : from carrots and yellow vegies 3. Hemoglobin: the of light skin

3 Integumentary system continued- Melanin in granules passes from melanocytes (same number in all races) to keratinocytes in stratum basale Digested by lysosomes - Variations in color - Protection from UV light vs vitamin D? Skin appendages Derived from epidermis but extend into dermis Include: 1. Hair and hair follicles 2. Sebaceous (oil) glands 3. Sweat (sudoiferous) glands 4. Nails Nails: Of hard keratin Corresponds to hooves and claws Grows from nail Functions of hair 1- less in man than other mammals 2- light touch of the skin 3- Protection scalp Parts - imbedded in skin - projecting above skin surface -Make up of hair hard -Three concentric layers: 1. Medulla (core) 2. Cortex (surrounds medulla) 3. Cuticle (single layers, overlapping) Types of hair Vellus:, hairs - Intermediate hairs - : longer, courser hair

4 Hair growth: averages mm/week Active: growing -Resting phase - then shed Hair loss: Thinning - Male pattern baldness Hair color Amount of melanin for black or brown; distinct form of melanin for red White: decreased melanin and air bubbles in the medulla Genetically determined though influenced by hormones and environment Sebaceous (oil) glands Entire body except palms and -Oils and Sweat glands -Entire skin surface except nipples and part of external genitalia -Prevent 500 cc or about liters a day! (is mostly water) - Humans most efficient (only have) -Produced in response to stress as well as heat Disorders of the integumentary system Burns: - Threat to life - Catastrophic loss of body fluids -Dehydration and fatal circulatory shock - Infection Types First degree epidermis: redness (e.g. ) Second degree and : blister Third degree - full thickness -Infections -Skin cancer Tumors of the skin, e.g. warts Cancer associated with UV exposure (also skin aging) -Aktinic keratosis premalignant -Basal cell - cells of stratum basale - Squamous cell - Melanoma melanocytes: most dangerous; recognition: A B - irregularity C Colors D - Diameter larger than mm

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