Integumentary System Tissues in combination
Functions of Integument <ul><li>Protection of underlying tissues </li></ul><ul><li>Excretion of salts, water, organic wast...
Skin is the largest organ of your body – 16% by weight <ul><li>2 Functional components </li></ul><ul><ul><li>Cutaneous mem...
Epidermis <ul><li>Stratified squamous epithelium in 4 (or 5) layers </li></ul><ul><ul><li>1. Stratum Germinativum (basale)...
<ul><li>2. Stratum spinosum </li></ul><ul><ul><li>Bound together by desmosomes </li></ul></ul><ul><ul><li>Several cells th...
<ul><li>4. Stratum lucidum * </li></ul><ul><ul><li>*only found on palms and soles </li></ul></ul><ul><ul><li>Clear layer <...
S. Corneum cont. <ul><li>Cells become thin and flat </li></ul><ul><li>Become packed with keratin </li></ul><ul><li>Organel...
Cornification <ul><li>Accumulation of keratin – keratinized  </li></ul><ul><li>Occurs everywhere except the surface of the...
Epidermal Ridges <ul><li>Deeper layers of epidermis form ridges </li></ul><ul><li>Increased contact with dermis – diffusio...
UV Radiation <ul><li>Vitamin D synthesis – sterol altered by UV </li></ul><ul><li>Stresses skin </li></ul><ul><ul><li>Brea...
Color of epidermis <ul><li>1. Underlying blood vessels – reddish </li></ul><ul><ul><li>In dermis </li></ul></ul><ul><li>2....
Melanin <ul><li>Secreted by melanocytes, passed to adjacent cells </li></ul><ul><ul><li>Everyone has approximately the sam...
Dermis <ul><li>1. Papillary (superficial) layer </li></ul><ul><li>2. Reticular (deep) layer </li></ul><ul><li>Both contain...
Papillary layer <ul><li>Loose CT </li></ul><ul><li>Capillaries and nerves that supply epidermis </li></ul><ul><li>Named fo...
Reticular layer <ul><li>Dense irregular CT </li></ul><ul><li>Collagen fibers extend into papillary layer </li></ul><ul><li...
Lines of Cleavage <ul><li>Bundles of collagen tend to run parallel </li></ul><ul><li>Different areas of body are oriented ...
Hypodermis <ul><li>Subcutaneous layer </li></ul><ul><li>Adipose tissue </li></ul><ul><li>Insulates against heat loss </li>...
Skin cancers <ul><li>Basal cell carcinoma – S. germinativum cells are affected, most common type </li></ul><ul><li>Squamou...
Accessory Structures <ul><li>Hair </li></ul><ul><ul><li>Found everywhere except: sides and soles of feet, palms of hands, ...
Hair Follicle <ul><li>Tube hair occupies  </li></ul><ul><li>Deep into dermis  </li></ul><ul><li>Structure </li></ul><ul><u...
Hair Structure <ul><li>Medulla – soft core closest to center of papilla; soft keratin </li></ul><ul><li>Cortex – farther o...
Hair types <ul><li>1. Vellus hair – peach fuzz </li></ul><ul><li>2. Terminal hair – heavy, dark, hair on head, eyebrows, e...
Hair loss may also be caused by  <ul><ul><li>Drugs (chemo) </li></ul></ul><ul><ul><li>Dietary factors </li></ul></ul><ul><...
Hair Functions <ul><li>Control heat loss </li></ul><ul><ul><li>Arrector pili – small smooth muscle that pulls on follicle ...
Nails <ul><li>Made of keratin at the nail root (not visible) </li></ul><ul><li>Lunula – pale crescent at base of nail </li...
Glands  <ul><li>Sebaceous glands </li></ul><ul><ul><li>Holocrine glands found along hair follicles </li></ul></ul><ul><ul>...
Sweat glands <ul><li>1. Apocrine sweat glands – stinky sweat (bacteria that eat this sweat contribute to the smell) </li><...
<ul><li>2. Merocrine sweat glands – watery sweat (99% water, some salt, waste) </li></ul><ul><ul><li>Cools the body  “sens...
Control of sweat glands <ul><li>Sebaceous and apocrine are hormonally controlled; all on or all off </li></ul><ul><li>Mero...
Ceruminous glands  <ul><li>Modified sweat glands in ear canal </li></ul><ul><li>Secretions mix with sebum to make  cerumen...
Nerve endings <ul><li>Pain – free nerve endings in epidermis </li></ul><ul><li>Touch </li></ul><ul><ul><li>Merkel’s discs ...
 
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Integumentary system

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Integumentary system

  1. 1. Integumentary System Tissues in combination
  2. 2. Functions of Integument <ul><li>Protection of underlying tissues </li></ul><ul><li>Excretion of salts, water, organic waste </li></ul><ul><li>Maintenance of normal body temp </li></ul><ul><li>Synthesis of vitamin D </li></ul><ul><li>Storage of nutrients </li></ul><ul><li>Sensitivity to touch, pressure, pain, temp </li></ul>
  3. 3. Skin is the largest organ of your body – 16% by weight <ul><li>2 Functional components </li></ul><ul><ul><li>Cutaneous membrane – layers of tissues </li></ul></ul><ul><ul><li>Accessory structures – hair, nails, glands </li></ul></ul><ul><li>Cutaneous membrane has 3 regions </li></ul><ul><ul><li>Epidermis – epithelial layer </li></ul></ul><ul><ul><li>Dermis – CT layers </li></ul></ul><ul><ul><li>Hypodermis – fat layer (deep) </li></ul></ul>
  4. 4. Epidermis <ul><li>Stratified squamous epithelium in 4 (or 5) layers </li></ul><ul><ul><li>1. Stratum Germinativum (basale) </li></ul></ul><ul><ul><ul><li>Deepest layer – basement membrane </li></ul></ul></ul><ul><ul><ul><li>Stem cells – replace shed cells </li></ul></ul></ul>
  5. 5. <ul><li>2. Stratum spinosum </li></ul><ul><ul><li>Bound together by desmosomes </li></ul></ul><ul><ul><li>Several cells thick </li></ul></ul><ul><ul><li>Spiky looking under microscope </li></ul></ul><ul><li>3. Stratum granulosum </li></ul><ul><ul><li>Grainy layer </li></ul></ul><ul><ul><li>Make keratohyalin </li></ul></ul>
  6. 6. <ul><li>4. Stratum lucidum * </li></ul><ul><ul><li>*only found on palms and soles </li></ul></ul><ul><ul><li>Clear layer </li></ul></ul><ul><ul><li>Makes eleidin </li></ul></ul><ul><li>5. Stratum corneum </li></ul><ul><ul><li>True keratin develops from keratohyalin and eleidin </li></ul></ul><ul><ul><ul><li>Keratin is tough, flexible, water resistant, fibrous protein </li></ul></ul></ul>
  7. 7. S. Corneum cont. <ul><li>Cells become thin and flat </li></ul><ul><li>Become packed with keratin </li></ul><ul><li>Organelles break down and cells die </li></ul><ul><li>Eventually sloughed off </li></ul><ul><li>From mitosis; 6 weeks to new epidermis </li></ul><ul><li>Relatively dry – unattractive to microorganisms </li></ul><ul><li>Lipids are secreted by glands to maintain barrier </li></ul><ul><li>Xerosis – dry skin </li></ul>
  8. 8. Cornification <ul><li>Accumulation of keratin – keratinized </li></ul><ul><li>Occurs everywhere except the surface of the eyes </li></ul><ul><li>Thin skin – 1.5 to 4mm; epidermis is .08mm, about 20 cell layers thick </li></ul><ul><li>Palms and soles have 30+ layers </li></ul>
  9. 9. Epidermal Ridges <ul><li>Deeper layers of epidermis form ridges </li></ul><ul><li>Increased contact with dermis – diffusion of nutrients </li></ul><ul><li>Base for fingerprints (genetically determined) </li></ul><ul><ul><li>Fingerprints provide grip </li></ul></ul><ul><li>Monitored by nerves for touch, pressure, pain, temp. info. </li></ul>
  10. 10. UV Radiation <ul><li>Vitamin D synthesis – sterol altered by UV </li></ul><ul><li>Stresses skin </li></ul><ul><ul><li>Breaks down underlying CT </li></ul></ul><ul><ul><ul><li>Wrinkles </li></ul></ul></ul><ul><ul><li>Skin cancer </li></ul></ul><ul><ul><li>Destroys folate – folate helps protect against spina bifida </li></ul></ul><ul><ul><li>Tanning beds are as risky as the sun </li></ul></ul>
  11. 11. Color of epidermis <ul><li>1. Underlying blood vessels – reddish </li></ul><ul><ul><li>In dermis </li></ul></ul><ul><li>2. Carotene – orange yellow pigment </li></ul><ul><ul><li>In epithelia </li></ul></ul><ul><li>3. Melanin – yellow brown to black </li></ul><ul><ul><li>In between stem cells </li></ul></ul>
  12. 12. Melanin <ul><li>Secreted by melanocytes, passed to adjacent cells </li></ul><ul><ul><li>Everyone has approximately the same number of melanocytes; but activity, and color and size of granules of melanin differs </li></ul></ul><ul><li>Absorbs UV radiation, protects deeper layers </li></ul><ul><li>Activity increases with exposure to UV </li></ul><ul><ul><li>Accelerates slowly – maxes about 10 days after initial exposure </li></ul></ul>
  13. 13. Dermis <ul><li>1. Papillary (superficial) layer </li></ul><ul><li>2. Reticular (deep) layer </li></ul><ul><li>Both contain fibers, blood vessels, lymphatic vessels, fat cells, muscle cells, nerve endings, and accessory structures </li></ul>
  14. 14. Papillary layer <ul><li>Loose CT </li></ul><ul><li>Capillaries and nerves that supply epidermis </li></ul><ul><li>Named for dermal papillae (bumps) that project between epidermal ridges </li></ul>
  15. 15. Reticular layer <ul><li>Dense irregular CT </li></ul><ul><li>Collagen fibers extend into papillary layer </li></ul><ul><li>Elastin fibers </li></ul>
  16. 16. Lines of Cleavage <ul><li>Bundles of collagen tend to run parallel </li></ul><ul><li>Different areas of body are oriented differently </li></ul><ul><li>Surgeons use these lines to minimize scarring, heal faster </li></ul><ul><li>Stretch marks – bundles that have been pulled apart by rapid weight gain or pregnancy (perpendicular to lines of cleavage) </li></ul>
  17. 17. Hypodermis <ul><li>Subcutaneous layer </li></ul><ul><li>Adipose tissue </li></ul><ul><li>Insulates against heat loss </li></ul><ul><li>Energy reserve </li></ul><ul><li>Cushioning for kidneys and babies </li></ul><ul><li>Collagen fibers extend into here from dermis </li></ul><ul><li>Hypodermic needle introduces drugs into fat layer, slowly enters circulation </li></ul>
  18. 18. Skin cancers <ul><li>Basal cell carcinoma – S. germinativum cells are affected, most common type </li></ul><ul><li>Squamous cell carcinoma – also epithelial, more deadly than basal cell </li></ul><ul><li>Melanoma – cancer of melanocytes, most deadly form, more likely from severe burns </li></ul><ul><ul><li>Size, shape, color </li></ul></ul><ul><li>Moles – benign tumors of melanocytes </li></ul>
  19. 19. Accessory Structures <ul><li>Hair </li></ul><ul><ul><li>Found everywhere except: sides and soles of feet, palms of hands, sides of fingers and toes, lips, portions of external genitalia </li></ul></ul><ul><ul><li>Color – variations in melanin </li></ul></ul><ul><ul><ul><li>Gray – pigment lessens </li></ul></ul></ul><ul><ul><ul><li>White – air bubble in shaft </li></ul></ul></ul>
  20. 20. Hair Follicle <ul><li>Tube hair occupies </li></ul><ul><li>Deep into dermis </li></ul><ul><li>Structure </li></ul><ul><ul><li>Papilla – bump containing nerves and blood vessels </li></ul></ul><ul><ul><li>Matrix – epithelium at base of follicle that forms hair, basal cells divide, cornification of outer layers </li></ul></ul>
  21. 21. Hair Structure <ul><li>Medulla – soft core closest to center of papilla; soft keratin </li></ul><ul><li>Cortex – farther out – hard keratin, stiffness </li></ul><ul><li>Cuticle – superficial – hard keratin coats hair </li></ul><ul><li>Root – enclosed by matrix, bulb of follicle </li></ul><ul><li>Shaft – the hair itself </li></ul><ul><ul><li>Straight hair – round in cross section </li></ul></ul><ul><ul><li>Curly hair – flat or oval in cross section </li></ul></ul>
  22. 22. Hair types <ul><li>1. Vellus hair – peach fuzz </li></ul><ul><li>2. Terminal hair – heavy, dark, hair on head, eyebrows, eyelashes, etc. </li></ul><ul><li>3. Intermediate hair – hair on arms and legs </li></ul><ul><li>Hormones change hair from one form to another </li></ul><ul><ul><li>Puberty </li></ul></ul><ul><ul><li>Male pattern baldness </li></ul></ul>
  23. 23. Hair loss may also be caused by <ul><ul><li>Drugs (chemo) </li></ul></ul><ul><ul><li>Dietary factors </li></ul></ul><ul><ul><li>Radiation </li></ul></ul><ul><ul><li>High fever </li></ul></ul><ul><ul><li>Stress </li></ul></ul><ul><ul><li>Pregnancy hormones </li></ul></ul><ul><li>Hair grows 1/3mm per day </li></ul><ul><li>Stays in scalp for 2 – 5 years </li></ul><ul><li>50 hairs lost per day is normal </li></ul>
  24. 24. Hair Functions <ul><li>Control heat loss </li></ul><ul><ul><li>Arrector pili – small smooth muscle that pulls on follicle to make hair stand up </li></ul></ul><ul><ul><ul><li>Increases trapped air insulation </li></ul></ul></ul><ul><ul><ul><li>Causes goosebumps in humans </li></ul></ul></ul><ul><li>Reduces friction </li></ul>
  25. 25. Nails <ul><li>Made of keratin at the nail root (not visible) </li></ul><ul><li>Lunula – pale crescent at base of nail </li></ul><ul><ul><li>Blood vessels are obscured </li></ul></ul><ul><li>Protection of finger and toe tips (claws in some animals) </li></ul>
  26. 26. Glands <ul><li>Sebaceous glands </li></ul><ul><ul><li>Holocrine glands found along hair follicles </li></ul></ul><ul><ul><li>Secrete sebum </li></ul></ul><ul><ul><ul><li>Inhibits bacterial growth </li></ul></ul></ul><ul><ul><ul><li>Lubricates and protects hair shaft and skin </li></ul></ul></ul><ul><ul><li>Contraction of arrector pili helps squeeze sebum onto skin surface </li></ul></ul><ul><ul><li>Sebaceous follicles discharge directly onto skin </li></ul></ul>
  27. 27. Sweat glands <ul><li>1. Apocrine sweat glands – stinky sweat (bacteria that eat this sweat contribute to the smell) </li></ul><ul><ul><li>Found in armpits, around nipples, groin </li></ul></ul><ul><ul><li>Associated with hair follicles </li></ul></ul><ul><ul><li>Send social chemical messages in mammals about sex </li></ul></ul>
  28. 28. <ul><li>2. Merocrine sweat glands – watery sweat (99% water, some salt, waste) </li></ul><ul><ul><li>Cools the body “sensible perspiration” </li></ul></ul><ul><ul><li>Discharge onto skin surface </li></ul></ul><ul><ul><li>Palms and soles – 3000 per sq. in. </li></ul></ul><ul><ul><li>Flushes out microorganisms </li></ul></ul><ul><ul><li>Smaller than apocrine glands </li></ul></ul>
  29. 29. Control of sweat glands <ul><li>Sebaceous and apocrine are hormonally controlled; all on or all off </li></ul><ul><li>Merocrine are nerve controlled, can be regional </li></ul><ul><ul><li>Sweaty palms </li></ul></ul>
  30. 30. Ceruminous glands <ul><li>Modified sweat glands in ear canal </li></ul><ul><li>Secretions mix with sebum to make cerumen – ear wax </li></ul><ul><ul><li>Protection </li></ul></ul><ul><ul><li>Bug repellent </li></ul></ul>
  31. 31. Nerve endings <ul><li>Pain – free nerve endings in epidermis </li></ul><ul><li>Touch </li></ul><ul><ul><li>Merkel’s discs – in epidermis </li></ul></ul><ul><ul><li>Meissner’s corpuscles – in papillae </li></ul></ul><ul><ul><li>Root hair plexus – around hair at base of follicle </li></ul></ul><ul><li>Pressure – Pacinian corpuscle – in hypodermis </li></ul><ul><li>Cold – Krause corpuscle – in dermis, round </li></ul><ul><li>Heat – Ruffini corpuscle – in dermis, flattened </li></ul>

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