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Chapter 4. Skin and Body Membranes. Body Membranes. Body Membranes : Covers surfaces, lines body cavities and forms protective (lubricating) sheets around organs. I. Classification of Body Membranes.
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Chapter 4 Skin and Body Membranes
Body Membranes • Body Membranes: Covers surfaces, lines body cavities and forms protective (lubricating) sheets around organs.
I. Classification of Body Membranes A. Epithelial Membranes: simple organs made of an epithelial sheet combined with a layer of connective tissue. • Cutaneous Membrane: Integumentary System (Skin) * Exposed to air/dry membrane • Mucous Membrane (mucosa) * Lines body cavities that are open to the exterior (ex: respiratory, digestive, urinary, reproductive tracts)
Epithelial Membranes, cont’d 3. Serous Membrane (serosa) * Occurs in pairs: - Parietal Layer lines body cavity - Visceral Layer covers the organs * Ex: Peritoneum – lines abdominal cavity, Pleura – surrounds lungs, Pericardium – surrounds heart
Connective Tissue Membrane • Ex. Synovial membrane • Lines fibrous capsules surround joints. *Membranes make FLUIDS and MUCUS!
II. Integumentary System • Cutaneous membrane, sweat & oil glands, hair and nails • Basic Skin Functions ~ Protection, insulations, excretion, synthesis of vitamin D ~ Cutaneous sensory receptors – touch pressure, temperature, and pain receptors
B. Structures of the Skin ~ Tissue of the Skin * Epidermis – outer layer/stratified squamous epithelium capable of keratinizing (hard and tough) ~ Burn or friction may cause epidermis and dermis to separate (blister)
Structures of the Skin, cont’d ~ Subcutaneous tissue/hypodermis – adipose * anchors skin to underlying organs * function: shock absorber, insulates, and forms curves
1. Epidermis • Avascular • Kerantinocytes (keratin – fibrous protein)
1. Epidermis, cont’d… • 5 Layers • Stratum basale (geminitivum) • Stratum spinosum • Stratum granulosum • Stratum lucidum • Stratum corneum
1. Epidermis, cont’d… • Melanocytes (melanin) • Sunlight stimulates melanin production (tan) • Freckles & Moles – accumulation of melanin
2. Dermis – “hide” - Leather • 2 Layers • Papillary layer – fingerprints,Meissner’s corpuscles – touch & pain. • Reticular layer – blood vessels & glands; collagen & elastic fibers; Pacinian corpuscles – deep pressure
2. Dermis, cont’d… • Fever – • Dermal capillaries swell • Skin red & warm • Heat radiates from skin
2. Dermis, cont’d… • Decubitus Ulcers (bed sores) • Poor circulation • Dead skin cells
C. Skin Color • Pigment (melanin & carotene)
C. Skin Color, cont’d… • Dermal blood vessels (oxygenated blood) • Cyanosis – poorly oxygenated blood (blue) • Erthema - blushing • Pallor or blanching - pale • Jaundice – Yellow; liver disorder • Bruises – black or blue (hematoma – blood mass)
D. Appendages of skin • Sebaceous glands (oil) • Sebum – lubricant • Kills bacteria • Active – adolescent (hormones) • Acne – infection of oil gland
D. Appendages of skin, cont’d… • Sweat glands • Eccrine sweat glands • Sweat • Antibacterial • Body heat regulation
D. Appendages of skin, Sweat glands, cont’d… • Apocrine sweat glands • Axillary – milky, yellowish, odorless • Bacteria causes body odor • Activated - puberty
D. Appendages of skin, cont’d… • Hair • Hair follicle/hair root/hair shaft/cuticle (split ends) • Hormones stimulate hair growth • Hair color - melanin
D. Appendages of skin, cont’d… • Nails • Keratinized dead cells • Nail bed – pink/rich blood supply • Lunula – white crescent at base of nail