1 / 53

Skin and Body Membranes

Skin and Body Membranes. Chapter 4. What are body membranes?. Cover surfaces, line cavities, protect organs 2 groups Epithelial membranes – cutaneous, mucous, serous Connective Tissue membranes – synovial membranes. Epithelial Membranes. Coving and lining membranes

Download Presentation

Skin and Body Membranes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.


Presentation Transcript

  1. Skin and Body Membranes Chapter 4

  2. What are body membranes? • Cover surfaces, line cavities, protect organs • 2 groups • Epithelial membranes – cutaneous, mucous, serous • Connective Tissue membranes – synovial membranes

  3. Epithelial Membranes • Coving and lining membranes • Do contain epithelial sheet, but all have connective tissue underneath • Simple organs

  4. Epithelial Membrane - Cutaneous • Skin • Superficial – keratinizing stratified squamous epithelium • Deep (dermis) – dense connective tissue • Exposed to air and dry membrane Figure 4.1a

  5. Epithelial Membrane - Mucous • Epithelium – varies per site, most often stratified squamous or simple columnar • Loose connective tissue – called lamina propria • Lines all body cavities open to exterior • What? • Respiratory, Digestive, Urinary, Reproductive • Wet membranes, bathed in secretions (or urine) • Adopted for absorption or secretion • Almost all produce mucus but urinary does not

  6. Epithelial Membranes - Serous • Superficial - Simple squamous • Deep – loose connective areolar • Line cavities closed to exterior (except dorsal body cavity and joint cavities) • What? Figure 4.1c–d

  7. Epithelial Membranes - Serous • Come in pairs • Parietal layer – lines wall of ventral body cavity, folds over on itself to form, always connected to wall • Visceral layer – covers outside layer of organ • Compare to balloon • Two layers separated by serous fluid – secreted by both layers, lay very close together • Why? • Name of serous membrane based on location • Peritoneum • Pleura • Pericardium

  8. Connective Tissue MembranesSynovial Membranes • Areolar connective tissue • Line fibrous capsules surrounding joints • Smooth surface • Secrete lubrication • Lines sacs of connective tissue of bursae and tendon sheaths Figure 4.2

  9. The Integumentary SystemSkin • Cutaneous Membrane • Include skin, sweat and oil glands, hair, and nails • Mostly protective

  10. Functions Table 4.1

  11. Functions • Upper layer contains keratin • Cornified (hardened) – protect from water loss • Rich capillary network and sweat glands • Controlled by nervous system • Regulate heat loss • Mini-excretory system • Urea, water, and salts lost • Manufac. Proteins imp. to immunity and Vit. D synthesis • Cutaneous Sensory Receptors in skin – touch, pressure, temperature, pain (part of nervous)

  12. Structure of the Skin • Epidermis – outermost layer • Stratified squamous able to keratinize • Dermis – underlying tissue • Dense connective tissue • Firmly connected, friction can separate • Blister – What happens? • Subcutaneous layer or hypodermis – adipose tissue • Not skin, anchors to organs • Shock absorber, insulator • Curves of woman

  13. Epidermis • Up to five layers thick • You get to learn them all in 2A!! • Avascular – shaving! • Most cells keratinocytes • Bottom layer stratum basale anchored to dermis by epidermal cells, receive nutrients via diffusion from dermis, millions of new cells daily, pushed outward (DEAD) • You will shed 40lb of skin in lifetime Figure 4.3

  14. Melanin • Pigment – yellow to brown to black • Produced by melanocytes found in stratum basale • Exposed to sun, produce more melanin • Collected in melanosomes, taken up by keratinocytes • Act as umbrella protecting DNA • Freckles or moles are concentrated melanin

  15. Herpes Simplex and the sun! • Sun exposure damages skin • Depresses immune system • Develop cold sore more often after sun bathing • Overexposure of skin to UV rad. can lead to skin cancer • Black individuals seldom have skin cancer • Power of melanin

  16. Dermis • Strong, stretchy envelop that holds you together • Hide – leather goods treated dermis • Dense Connective Tissue • Papillary layer – upper • Reticular layer - lower • Varies in thickness – feet/hands compared to eyelids Figure 4.4

  17. Papillary Layer of Dermis • Uneven, projections called dermal papillae • Contain capillary loops which nourish epidermis • Some contain pain and touch receptors • Hands and feet – looped and whorl patterns for friction and grip • Determined genetically - fingerprints Figure 4.4

  18. Reticular Layer of Dermis • Blood vessels, sweat and oil glands, deep pressure receptors • Phagocytes prevent bacteria

  19. Dermis • Collagen and elastic fibers • Collagen – toughness, attract and bind water, keep skin hydrated • Elastic – give skin elasticity • As age both decrease, subcutaneous looses fat, sag and wrinkle • Blood vessels to regulated heat • Hot – hot blood, radiate heat • Cold – bypass capillaries • Rich nerve supply – chapter 7

  20. Decubitis Ulcers • Restriction of blood supply results in cell death, possibly skin ulcers • Bed sores – bedridden patients not turned, pressure points • Permanent damage results in ulceration Figure 4.5

  21. Skin Color • 3 pigments contribute to skin color • Melanin – amount and kind in epidermis • Carotene – deposit in stratum corneum and subcutaneous tissue, orange-yellow pigment • Oxygen-rich hemoglobin – in dermal blood vessels • Think about variations!

  22. Cyanosis • Hemoglobin poorly oxygenated, blood and skin of Caucasians appear blue • Heart failure, breathing disorders • In black people, skin does not appear blue due to masking melanin – mucous membranes and nails http://meded.ucsd.edu/clinicalimg/upper_cyanosis.htm

  23. Emotions and Skin Color • Redness (erythema) – embarrassment, fever, hypertension, inflammation, or allergy • Pallor (blanching) – emotional stress (fear, anger), anemia, hypotension, impaired blood flow • Jaundice (yellow) – liver disorder excess bile pigments absorbed by blood, transported and deposited in tissues • Bruises – escaped blood has clotted in tissue, hematomas, deficiency Vit C or hemophilia

  24. Appendages of the Skin • Cutaneous Glands • Hair and hair follicles • Nails • Arise from epidermis, play role in homeostasis

  25. Cutaneous Glands • All exocrine glands – release secretions to skin surface • Formed by cells of stratum basale, push into dermis • 2 Types • Sebaceous (oil) glands • Sweat glands

  26. Cutaneous GlandsSebaceous Glands • All over body except hands and feet • Most ducts empty into hair follicle, some to surface of skin • Sebum = product • Oily substances • Fragmented cells • Lubricant – soft, moist, hair not brittle • Chemicals to kill bacteria • Become very active when male hormones produced = oily skin Figure 4.6a

  27. Imbalance of Sebaceous Glands • Whitehead – gland blocked by sebum • Blackhead – material oxidizes and dries • Acne – active infection of glands • Mild or severe, perm. scaring. • Seborrhea (cradle cap) – overactive sebaceous gland, raised pink lesions form yellow brown crust http://www.medical-look.com/Skin_diseases/Acne.html

  28. Cutaneous GlandsSweat Glands – Sudoriferous Glands • Widely distributed in skin - +2.5 mil/person • 2 types • Eccrine glands – more #’s, all over body • Produce sweat • Effective heat regulation • Nerve endings, stimulate sweat production • Apocrine glands – Axillary and genital areas • Larger than eccrine glands • Ducts empty into hair follicle • Puberty, under direction of androgens (♂ hormones) • Activated by nerves during pain, stress, sexual foreplay

  29. Sweat – Eccrine Gland • Clear secretion • Mostly water + salts (NaCl), Vit C, metabolic waste (urea), lactic acid • Acidic – pH 4-6, inhibits bacterial growth • Reaches surface through pore • Pores on face not sweat pores, but external outlets of hair follicle • Excreted when temp. ↑, can lose up to 7 L of water Figure 4.6b

  30. Product of Apocrine Gland • Fatty acids and proteins in addition to eccrine secretion • Milky or yellowish color • Odorless unless bacteria on skin use proteins for growth – musky, unpleasant odor • Produced almost continually http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/Skin.htm

  31. Hair and Hair FolliclesHair • Has lost most of evolutionary purpose • Some protective features – head, eyes, nose

  32. Hair Figure 4.7a • Produced by hair follicle • Flexible epithelial structure • Shaft – projection out of skin • Hair formed from well nourished stratum basale epithelial in matrix (growing) • As push farther from growing region, keratinize and die • Most of hair shaft dead cells like epidermis Figure 4.7c

  33. Hair Figure 4.7b • Medulla, Cortex, Cuticle • Cuticle – single layer of cells that overlap, shingles • keeps hair apart, matting • heavily keratinized – strength, inner compacted • Wears out at ends – splint ends • Melanocytes – hair bulb, produce hair color, melanin – yellow, rust, brown, black Figure 4.8

  34. More Hair • Different shapes and sizes – eyebrows, head, body, etc. • Oval hair shaft – smooth, wavy • Flat, ribbonlike – curly or kinky • Round shaft – straight and course • Found all over body except hands, feet, lips, nipples • Among fastest growing tissue • Hormones account for development of hairy regions – scalp, public, axillary

  35. Hair Follicle • Epidermal sheath – inner, epithelial tissue, forms hair • Dermal sheath – outer, dermal connective tissue, supplies blood to ES and supports • Papilla provides blood supply to hair bulb

  36. Hair Follicle • Hair follicle slanted • Arrector pili muscle • Connects hair follicle to dermal tissue • Muscles contract, hair stands, dimpling of skin • Keeps animals warm in winter, added layer of warmed air • Not useful to humans

  37. Nails • Modification of epidermis, like hoof or claw • Free edge, body, root • Nail fold or cuticle • Stratum basale – nail bed, thickened proximal area is nail matrix (growth), cells heavily keratinized and dead • Colorless, look pink due to blood supply • Lunula – white crescent Figure 4.9

  38. Homeostatic Imbalances of Skin • When something goes wrong, very visible • Most diseases caused by allergies, bacterial, viral, or fungal infections • More damaging are burn and cancers

  39. Infections and AllergiesAthlete’s Foot • Itchy, red, peeling skin • Fungal infection • Tinea pedis • Can affect other areas of skin • Ringworm http://www.squidoo.com/natural-cure-for-athletes-foot-x

  40. Infections and AllergiesBoils and Carbuncles http://www.mayoclinic.com/health/medical/IM01272 • Inflammation of hair follicles and sebaceous glands • Carbuncles – boils caused by bacterial infections like Staphylococcus aureus http://www.dshs.state.tx.us/idcu/health/antibiotic_resistance/mrsa/picpage.asp

  41. Infections and AllergiesCold Sores • Fluid filled blisters • Herpes simplex virus • Localized to cutaneous nerve where dormant until stress, fever, UV radiation • Lips or oral mucosa http://www.stanford.edu/group/virus/herpes/2000/herpes2000v1.html

  42. Infections and AllergiesContact Dermatitis • Itching, redness, swelling, eventual blistering • Exposure to chemicals that elicit allergic rxn • Poison ivy http://mmcenters.discoveryhospital.com/shared/enc/img_htm/Derm-12.htm

  43. Infections and AllergiesImpetigo • Pink, water filled, raised lesions • Normally around nose and mouth • Develop yellow crust than rupture • Caused by staphylococcus infection • Common in elementary school aged children http://www.impetigodoctor.com/impetigo-photo.htm

  44. Infections and AllergiesPsoriasis • Chronic condition • Overproduction of skin cells • Reddened epidermal lesions covered with dry, silvery scales • Itch, burn, crack, bleed • Autoimmune disorder • Trauma, stress, hormonal changes, infections http://www.psoriasite.com/

  45. Importance of skin • Skin only paper towel thick, when damaged affects all organs systems • Metabolism accelerates or impaired • Immune system changes • Cardiovascular system may fail

  46. Burns • Burn – tissue damage and cell death by intense heat, electricity, UV radiation, chemical • 2 life threatening problems result from burns • 1) Loss of supply of fluids containing proteins and electrolytes that seep from burns • Dehydration and electrolyte imbalance follow – shut down of kidneys and circulatory shock • 2) Infections – leading cause of death • Burned skin sterile for 24 hours • Pathogens – bacteria and fungus multiply in nutrient rich dead tissue • Immune system suppressed

  47. Burns - Classification • First degree burns – only epidermis damaged, red, swollen, sunburn • Second degree burns – epidermis and upper region of dermis, red, painful, blisters, no permanent scars if prevent infection • Both 1 and 2 partial-thickness burns • Third degree burns – full thickness burn, destroy entire thickness of skin • Appears blanched or blackened, nerves destroyed so area not painful • Regeneration not possible, grafting to cover tissue

  48. When are burns critical? • Over 25% of body has second degree burns • Over 10% of body has third degree burns • Third degree burns on face, hands or feet • Face dangerous why?

  49. Skin Cancer • 1 in 5 Americans • Basal Cell Carcinoma • Least malignant and most common • Cell of stratum basale • Do not form keratin, no boundary between dermis and epidermis • Usually on sun exposed area • Slow-growing • 99% cure rate when surgically removed Figure 4.12

  50. Skin Cancer • Squamous Cell Carcinoma • Cells of stratum spinosum • Scaly, reddened papule to shallow ulcer with firm raised border • Scalp, ears, dorsum of hands, lower lip • Grows rapidly, metastasizes to lymph nodes if not removed • Sun induced • Surgical removal and/or radiation therapy

More Related