Integumentary System PDF

Skin: protection, body temp regulation, excretion, vitamin D production, sensory reception Skin and Hypodermis: Integumentary system is skin and its appendages like hair, nails, skin glands Skin 2 layers: epidermis (superficial) and dermis (deeper) Deepest but not in system is HYPODERMIS= made o...

Skin: protection, body temp regulation, excretion, vitamin D production, sensory reception Skin and Hypodermis: Integumentary system is skin and its appendages like hair, nails, skin glands Skin 2 layers: epidermis (superficial) and dermis (deeper) Deepest but not in system is HYPODERMIS= made of areolar and adipose tissues aka superficial fascia Fascia= wrapping, packaging and insulating materials of the deep body structures Fascia is a dense, connective tissue layer Fascia extensions from internal surface invest into deeper structures, like individual muscles, neurovascular bundles as investing fascia EPIDERMIS - Made of KERATINIZED STRATIFIED SQUAMOS EPITHELIUM - From bottom to top: - Basale aka germinativum - Spinosum - Granulosum - Lucidum in thick skin only - Corneum - Dermis meets epidermis via epidermal ridge which meets dermal papilla - Epidermis has 4 mail cell types - Keratinocytes- in the stratum spinosum, produce keratin, fibrous - Melanocytes- in basal layer, make pigment - Tactile epithelial cells- in basal layer, attached to sensory nerve endings - Dendritic- in stratum spinosum, part of immune system, macrophage like - Layers of Epidermis (bottom to top) - BASALE: deepest layer, actively provided and producing new cells - SPINOSUM= spiny layer, resist tension and contain protein pre-keratin, among the keratinocytes are star shaped DENDRITIC cells, has layers of keratinoctyes - Granulosum= ketatinocyte layers that contain keratohyalin granules - Lucidum= clear layer only in thick skin, few rows of flat, dead keratinocytes - Corneoum= horny layer, thick layers dead keratinocytes and thickend plasma membrane, protet skin from abrasion and penetration - DERMIS - Strong, flexible connective tissue made of skin and blood vessels - 2 layers - Papillary dermis - Made of loose areolar connective tissue and include dermal papillae - Dermal papillae lay on dermal ridge - Epidermal ridges are friction ridges which are elevations of dermal ridges making the fingerprints - Reticular dermis= 80% of thickness, is made of dense irregular connective tissue - Dermal modifications - Tension lines or Langer lines or cleavage lines= separate between collagen fibers, spiral longitudinally in limbs and transversely in neck and trunk in surgery for repair and collage fiber is skin strength - FLEXURE LINES= creases in palms and wrists - Pigments= skin color - Melanin race and genetics - Hemoglobin - Pink skin if oxygenated - Cyanosis is blue skin due to reduction in blood flow or oxygenation - Carotene= yellow skin due to carrots - Bilirubin= yellow pigment due to metabolism of hemoglobin, buildup= jaundice - NAILS - Scalelike modification of epidermis - Made of hard keratin - Parts are free edge, nail plate, root - Nail folds are sides - Eponychium= cuticle - HAIR - Flexible strand of dead, keratinized cells - Hard keratin is tough and durable - Hair has root embedded in the skin and Shaft project above skin surface - CONCENTRIC HAIR LAYERS of HAIR KERATINIZED CELLS - Center core= medulla - Cortex= surround medulla - Cuticle= outermost layer - Appendages of the skin= hair - Hair follicles extend from epidermis into dermis - Hair bulbs are deep and expanded end of the hair follicle - Root plexus is the knot of sensory nerves around the hair bulb - Arrector pili muscle= bundle of smooth muscle - Attached to hair follicle and cause hair to stand in goose bump - Skin glands - 2 types of sweat glands - ECCRINE= most numerous, make true sweat - Apocrine= axillary, anal, and genital areas - Make thick, cloudy sweat oil and ferment bacteria for smell - Modified apocrine glands are ceruminous and mammary - Ceruminous is ear wax= cerumen - Mammary is milk production - Sebaceous Glands - Over entire body except palms and soles - Secrete sebum, oil - Simple alveolar gland - Sebum collects dirt, softens/lubricate hair and skin - Skin ligaments= L. retinacula cutis - Many small fibrous bands extend through subcutaneous tissue and attach to deep surface of dermis to deep fascia - Determine mobility of skin over deep structures - Skin ligaments are long and developed in breasts= suspensory weight ligament - Burns - Classified by severity - 1^st^= only upper epidermis - 2^nd^= epidermis and upper dermis - Blisters, little scarring - 3^rd^= consumes thickness of skin, white, red, black burn - Cancer - Basal= least malignant and most common - Squamous= arises from keratinocytes of stratum spinosum - Melanoma= deadly, cancer of melanocytes Majority of skin is keratinocytes and pre-keratin is in basal Fully differentiated keratinocytes are in the corneum, at this point keratinocytes can also be called corneocytes which will shed in epidermal turnover Hypodermis= insulation and protection aka subcutaneous tissue, deepest layer of system Spinosome contains desmoses, desmosoes are cell to cell adhesion proteins and hold keratinocytes together, dosmosoems give kertainocytes in the spinosum layer their spiny appearance, spiny desmosomes= spinosum= strength