Ch. 5 integumentary system - part 1
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Chapter 5 discusses the structure and functions of the skin and its derivatives, highlighting its protective roles against damage, regulation of temperature, and sensory reception. It details the composition of the epidermis and dermis, including cell types and layers, with functions tied to keratin production and pigmentation. Additionally, it addresses skin aging, healing processes, and conditions such as bedsores and tattoos.
Ch. 5 integumentary system - part 1
- 1. Chapter 5 Visit Or Site:
- 2. Skin and its derivatives (sweat & oil glands, hairs, nails)
- 3. Protection from: Mechanical damage (bumps & cuts) Chemical damage (acids & bases) Thermal damage (heat/cold) Bacteria UV radiation Desiccation (drying out) Temperature regulation (sweat glands) Excrete urea Synthesize Vitamin D Immunity Sensory reception (touch, heat, pain, pressure)
- 5. Two regions: 1.1. EpidermisEpidermis – keratinized stratified squamous epithelium 2.2. DermisDermis – fibrous connective tissue HypodermisHypodermis (subcutaneous fascia) Adipose tissue underneath skin Anchor skin to muscle below Shock absorber Store fat Insulation
- 6. Cells of the epidermis: 1.1. KeratinocytesKeratinocytes Produce keratinkeratin = fibrous protein Growth starts in deepest epidermal layer (stratum basalestratum basale) pushed upward by new cells underneath Top layer = dead, scalelike structures 1.1. MelanocytesMelanocytes Produce melaninmelanin = pigment (yellow/brown/black) Melanin granules taken up by nearby keratinocytes Shields DNA from UV radiation
- 8. “Overcoat” for body Protect against abrasion, penetration, & water loss (keratin & glycolipids) 20-30 cells thick Shingle-like dead cells Clear, flat, dead cells Thick layer on palms of hands, soles of feet Cells become flatter, full of keratin Water-resistant glycolipid fills spaces Thick bundles of pre-keratin Abundant melanin granules Single row of stem cells Receive nutrients from dermis Rapid cell division Stratum BasaleStratum Basale (basal layer)(basal layer) Stratum SpinosumStratum Spinosum (prickly layer)(prickly layer) Stratum GranulosumStratum Granulosum (granular layer)(granular layer) Stratum LucidumStratum Lucidum (clear layer)(clear layer) Stratum CorneumStratum Corneum (horny layer)(horny layer)
- 10. Strong, flexible connective tissue Semi-fluid matrix with fibers (collagen, elastic) Leather “hide” of animals Contains: nerve fibers blood vessels lymph vessels hair follicles oil glands sweat glands CellsCells: fibroblasts, macrophages, mast cells, WBC’s
- 12. 1.1. Papillary LayerPapillary Layer:: Upper part of dermis Dermal papillaeDermal papillae = peg-like projections Contain capillary loops Free nerve endings Touch receptors (MeissnerMeissner’s corpuscles’s corpuscles) Forms ridges (large mounds) increases friction to enhance gripping ability on fingers & feet Friction ridge pattern = fingerprintsfingerprints
- 14. 2.2. Reticular LayerReticular Layer:: Deepest skin layer Dense, fibrous connective tissue Contains blood vessels, sweat & oil glands, pressure receptors (Pacinian corpusclesPacinian corpuscles), WBC’s Collagen fibers in bundles form cleavage (tension)cleavage (tension) lineslines Incisions made parallelparallel to line heal more readily
- 16. CollagenCollagen: give skin strength; binds water (hydrate skin) Elastic fibersElastic fibers: stretch-recoil properties of skin Aging: fewer fibers, less subcutaneous fat skin loses elasticity and sags/wrinkles Extreme stretching of skin (pregnancy): dermal tearing leaves white scars = “stretch marks”
- 17. BlisterBlister: separation of epidermal and dermal layers Blood vessels in dermis: maintain body temp. CoolingCooling: Capillaries swell with heated blood skin becomes red and warm radiate heat Conserve heatConserve heat: blood bypasses capillaries to skin BedsoresBedsores: if blood (O2) is restricted to cells skin cells die & cause ulcers Bedridden patients need to be turned regularly TattoosTattoos: deposit pigment within dermis