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Chapter 4

Chapter 4. Skin and Body Membranes. BODY MEMBRANES. _________________________cover surfaces,line body cavities and forms protective-sometimes lubricating –sheets around organs. I.Classification of Body Membranes. A) EPITHELIAL MEMBRANES Covering and lining membranes

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Chapter 4

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  1. Chapter 4 Skin and Body Membranes

  2. BODY MEMBRANES • _________________________cover surfaces,line body cavities and forms protective-sometimes lubricating –sheets around organs

  3. I.Classification of Body Membranes • A) EPITHELIAL MEMBRANES • Covering and lining membranes • All have an underlying sheet of connective tissue

  4. 1) Cutaneous Membranes= skin • Superficial epidermis is____________________________________ • Underlying dermis is dense(fibrous) connective tissue.The superficial tissue is exposed to air and is a ________________________________ Composed of keratinizing stratified squamous epithelial Dry membrane

  5. 2) Mucous Membranes-made of varying types of epithelial tissue resting on a loose connective tissue called ____________________ and lines all membranes that open to the exterior(hallow organs of respiratory tract,digestive,urinary and reproductive… • Mucosa refers to location,not cellular makeup….But most mucosa are stratified squamous (mouth and esophagus) epithelium or simple columnar (rest of digestive tract)----all wet and bathed in secretions) Lamina propria

  6. 3)Serous membranes(serosa)- • Has a layer of simple squamous epithelium on a thin layer of ________________________________ • Serosa are closed to the exterior (except for dorsal body cavities and joint cavities) Areolar connective tissue

  7. Occur in pairs…The __________________lines a specific portion of the ventral body cavity • Parietal layer folds in itself to form ________________-covers outside of the organs in that cavity • Serous layers separated by___________________-secreted by both membranes Serous fluid Parietal layer Visceral layer

  8. Serous fluid allows organs to slide against ea. Other and cavity w/o friction

  9. SEROUS NAMES RELATED TO LOCATION peritoneum • ______________________covers abdominal cavity • ____________________-surrounds lungs • _______________________surrounds heart pleural pericardium

  10. Connective Tissue membranes • Composed of ______________________and has NO epithelial cells-line capsules surrounding joints • Line small sacs of connective tissue called bursae and the tubelike tendon sheath----all cushioning organs against each other and tendon across bone Soft areolar connective tissue

  11. II.The Integumentary Sysyem(skin)-cutaneous membrane • The Integumentary Sysyem(skin)-cutaneous membrane • functions –most importantly protective….against mechanical damage,chemical damage, • bacterial damage, • UV effects,thermal effects and dessication(drying out) • ---also aids in controlling body heat • ---aids in excretion of urea and uric acid • ----synthesizes Vitamin D

  12. The uppermost layer is full of _____________-and is cornified or hardened-help prevent water loss • Capillaries and sweat glands work on thermal control • ____________sense touch,pressure,temperature and pain keratin Cutaneous sensory receptors

  13. Structure of skin • Epidermis-stratified squamous epithelial capable of keratinizing(hardening) • _________-underneath-mostly dense connective tissue • Epidermis and dermis strongly connected,but some abuse can cause them to separate—interstitial fluid comes between layers making a _____________ • _____________is below dermis and mostly adipose----not actually considered part of skin,but attaches skin to organs beneath---works as “shock absorber” and insulates from extreme temperatures Subcutaneous tissue dermis blister

  14. 1)Epidermis- strata • has 5 layers or _______________.From inside out they are stratum basale,spinosum,granulosum,lucidum and corneum • avascular • most cells are ______________________________which make keratin keratinocytes

  15. Stratum basale-closest to dermis and connected along a wavy borderline.Contains epidermal cells that that get the most nourishment by diffusion from dermis;constant cell division-MILLIONS OF NEW CELLS DAILY(also called stratum germanitivum),daughter cells pushed upward • Stratum Spinosum and stratum granulosum become flatter and increasingly full of keratin

  16. When the previous cells die,they form the clear _________________________________-not in all skin regions-only where skin is hairless and extra thick-ie.palms and soles;it secretes a water repellent glycolipid into extracellular space;distant from blood supply,so little nutrients-doomed cells Stratum lucidum

  17. OUTERMOST Stratum corneum—20-30 cells layers thick and is ¾ of epidermal thickness;cornified,shinglelike dad cells,filled w/ keratin;protects lower cells;dandruff sloughs off from here • We have a totally new epidermis every 25-45 days • ___________________pigment that ranges in color from yellow to brown to black produced by melanocytes(in stratum basale).When skin is exposed to sun,this stimulates these cells tomake more of the pigment---THUS tanning melanin

  18. Melanin accumulates in membrane bound granules called __________________.They move to the end of the melanocytes and taken up by keratinocytes .THERE,melanin froms a pigment umbrella over superficial side of nuclei-shielding DNA from UV • _______________and moles are where melanin are concentrated in one spot melanosomes freckles

  19. 2)dermis-‘hide Dermal papillae Papillary layer • strong,stretchy • dense fibrous connective tissue • ___________________upper dermal region;______________-peglike projections from superior surface-many containing capillary loops-thus nutrients;some have pain receptors-___________________ or touch receptors-_________________________________ Free-nerve endings Meissner’s corpuscles

  20. Has whorled rings on soles and palms,increasing friction and gripping ability----genetically determined…..sweat pores provide for fingerprints

  21. Reticular layer • 2)_______________________________deepest skin layer w/blood vessels,sweat and oil glands and _______________________________deep pressure receptors;phagocytes act here at reticular layer • Collagen and elastic fibers found in dermis.collagen gives toughness and attract water for hydration.Elasisic fibers give elasticity that declines w/age • Many blood vessels help w/ body temp.homeostasis.skin is red when hot due to engorging of blood Pacinian corpuscles

  22. ___________________________________ happen in bedridden patients not turned regularily-pressure restricts blood supply and redness when pressure is released • Rich nerve supply Debicutus ulcers

  23. C-Skin Color-3 pigments: • 1-melanin in epidermis • 2-carotene in stratum corneum and subcutaneous tissue • 3-O2-rich hemoglobin in dermis • ----varying amounts of thr above create the numerous skin colors.Which is showing up more in Caucasians?_________________________ • ________________________hemoglobin is poorly oxygenated---can happen during heart failure and severe bleeding hemoglobin cyanosis

  24. What else affects skin color?: • Emotions and various disease states: • ___________________-redness-blushing,hypertension,inflammation,allergy • ___________________-blanching-pale—fear,anger also anemia,low blood pressure,impaired blood flow • ___________________-yellowness-liver disorder • ____________-sites wher blood has escaped and clotted in tissue spaces;can happen w/disese or vitamin C deficiency • _________________-clotted blood mass jaundice pallor erythema hematomas bruises

  25. D.Appendages of the Skin Cutaneous glands • 1-__________________________________-exocrine glands-release secretions to skin’s surface via ducts • a)Sebaceous glands-oil glands-excepts on palms and soles—some open into hair follicle and some to surface • ________________-is product-clump of oil and cells;keeps skin moist and prevents hair from drying out sebum

  26. ______________(sudoriferous glands)-many in the skin-2 types: 1)eccrine glands-all over body and make sweat(mostly water,NaCl,vitamin C and tarces of metabolic wastes(ammonia, urea,uric acid and lactic acid.It is acidic and inhibits bacteria….sweat comes through a poer(not same as facial pores);helps regulate temp.(37 C Sweat glands

  27. Apocrine glands • 2)_____________________________-mostly at axillary and genital areas;ducts empty into hair follicles;contains fatty acids and proteins—giving milky/yellowish color.It is odorless,but that changes whe bacteria use it as food:function at onset of puberty regulated by androgens(male sex hormones)----have been connected to sexual foreplay

  28. 3-Hair and Hair Follicles • . • 1)Hairs made by hair follicles and is flexible epithelial structure;root in ________________and shaft protrudes It is formed by mitosis of stratum basale epithelial cells in matrix(growth zone)-become keratinized and die as pushed forward---mostly hair contains protein • Hair has central core called a medulla surrounded by a cortex.This is covered by a cuticle(most keratinized region)-gives strength • Hair pigments made by melanocytes in hair bulb Hair follice

  29. Variety of shapes and sizes(eyebrows v. head then skin hair).If shaft is flat and ribbonlike-hair curly or kinky.If shaft is round-straight or coarse hair • Hair all over except soles,palms,nipples and lips • Fastest growing tissue in body • Have hormonal control

  30. 2) hair follicles-contain inner epidermal sheath that forms hair/outer dermal sheath is connective tissue/papilla yield blood supply to matrix in hair bulb • ______________________________smooth muscle that raise hair in response to temp Errector pilli

  31. Free edge Nail matrix • 3) Nails-scalelike product of dermis(corresponds to hoof or nail) • Each nail has a _______________,a body(visible and a root(imbedded in skin) • Nail bed in stratum basale and inner ____________________,responsible for growth-cells become keratinized and die • Part appears pink due to vascularization in dermis • ___________________ appears white lunula

  32. E.Homeostatic imbalances of skin • 1) Infections and Allergies • ___________________________-fungal,itchy red ,peeling skin(tinea pedis) • Boils and Carbuncles-inflammation of hair follicles and sebaceous glands—often dorsal neck.Carbuncles are caused by bacteria-esp. Staphylococcus aureus Athlete’s foot

  33. _____________________-small fluid filled(fever blisters)-itch and sting –caused by a herpes simplex virus-can be activated from dormancy from emotions,fever,UV light-usually around lips or oral mucosa • _____________________________-itchy,red,swelling and turns into blisters-exposure to chemicals like poison ivy Cold sores Contact dermatitis

  34. ___________________-pink,water-filled raised lesions around nose and mouth;w/yellow crust;caused by Staphylococcus • _____________________-chronic overproduction of cells w/ red epidermal lesions—probably autoimmune impetigo psoriasis

  35. 2-burns-tissue damage and cell death caused intense heat,electricity,UV light or certain chemicals---This can have a domino effect on several organ systems • destroys cells • Life threatening from 1) loss of fluids as they seep from burned surface-dehydrating and fluid imbalance-could shut down kidneys and cause circulatory shock

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