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S KIN AND THE I NTEGUMENTARY S YSTEM Chapter 6. S KIN IS … is the largest & heaviest organ in the body. covered in hair. vital in maintaining homeostasis.

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Presentation on theme: "S KIN AND THE I NTEGUMENTARY S YSTEM Chapter 6. S KIN IS … is the largest & heaviest organ in the body. covered in hair. vital in maintaining homeostasis."— Presentation transcript:

1 S KIN AND THE I NTEGUMENTARY S YSTEM Chapter 6

2 S KIN IS … is the largest & heaviest organ in the body. covered in hair. vital in maintaining homeostasis. a protective barrier. a.k.a. the cutaneous membrane.

3 S KIN IS … part of the integumentary system. divided into three distinct layers: EPIDERMIS – outer layer DERMIS – middle layer SUBCUTANEOUS – bottom layer (Not a true skin layer )

4 EPIDERMIS Stratified squamous epithelium Old cells die are pushed up Cytoplasm hardens, fills with keratin KERITINIZATION Forms tough, waterproof layer - STRATUM CORNEUM

5 EPIDERMAL LAYERS Stratum corneum Stratum lucidum Only in thick skin Stratum granulosum Stratum spinosum Stratum basale

6 MICROSCOPIC EPIDERMIS

7 EPIDERMAL PROTECTION Stratum basale contains MELANOCYTES Produce MELANIN Dark pigment in granules that absorbs UV radiation Granules spread to nearby cells

8 SKIN COLOR Everyone has the same # of melanocytes Skin color depends on amount of melanin produced Other factors: Blood supply Beta – carotene Bilirubin Dark Skin Light Skin

9 THE KING OF POP What’s up with M.J.’s skin? Vitiligo – disorder in which the skin’s melanocytes are destroyed

10 VITLIGO Possible causes: Body is allergic to its own melanocytes Cells destroy themselves during pigment creation FYI – Cancer patients can develop vitiligo after treatment; the weird thing? The vitiligo actually seems to stop the spread of the disease!

11 BACK TO M.J. Underwent repigmentation Turn white patches dark again. Process failed Went through depigmentation to reverse it Monobenzene is used to bleach the skin until it’s all the same color If he stopped the treatments, he would turn back

12 ALBINISM Body is unable to produce or distribute melanin due to possible genetic defects High risk of skin cancer and eye problems

13 PSORIASIS Excessive growth and reproduction of keratinocytes followed by inflammation Caused by the immune system mistakenly reacting Speeds up creation of new cells and slows loss

14 WHAT ARE THOSE WHITE SPOTS ON MY FINGERNAILS? Leukonychia Can be caused by trauma Not a calcium deficiency Zinc deficiency is more pronounced

15 HOW THICK IS YOUR SKIN? Epidermis:.5 mm on eyelids Up to 1.5 mm on palms/soles Dermis:.3mm on eyelids 3 mm on upper back

16 DERMIS Directly below epidermis Dermal papillae project upwards into epidermis Produce fingerprints Made mostly of dense connective tissue

17 DERMAL STRUCTURES

18 BEDSORES Interference with blood flow to the dermis can kill epidermal cells Lying in one position too long causes weight of body to block skin’s blood supply A.k.a. PRESSURE ULCER Treatment includes shifting the patient frequently and keeping the wound clean

19 SUBCUTANEOUS LAYER A.k.a. HYPODERMIS Loose connective and adipose tissue Insulation Major blood supply

20 SEVERITY OF BURNS

21 INJECTIONS SUBCUTANEOUS INJECTION Flu shot, penicillin INTRADERMAL TB test INTRAMUSCULAR Epinephrine injection

22 ACCESSORY ORGANS OF THE SKIN NAILS HAIR FOLLICLES SEBACEOUS GLANDS SUDORIFEROUS GLANDS

23 NAILS Protective coverings NAIL ROOT & LUNULA contain actively dividing cells Cells die and become keratinized forming nail body

24 HAIR FOLLICLES Hair development Specialized epidermal tissue Nourished by dermal blood supply Cells divide near base and become keratinized

25 HAIR FOLLICLES Hair color is determined by melanocytes near root More melanin produced, darker hair ARRECTOR PILI- smooth muscles that control “goose bumps”

26 SEBACEOUS GLAND Specialized epithelial gland that produces SEBUM Oily mixture that keeps hair and skin soft, pliable and waterproof Attached to follicles

27 SUDORIFEROUS (SWEAT) GLANDS Tiny tube that is attached to a coil in dermis ECCRINE GLANDS respond to temperature Sweat comes out of PORE Forehead, neck, back

28 SUDOIFEROUS (SWEAT) GLANDS APOCRINE GLANDS Respond to emotions Active at puberty Groin, axillary regions

29 SKIN SENSORY RECEPTORS The skin has receptors for “touch” Heat Pressure Pain Cold

30 SKIN TOUCH RECEPTORS MERKEL’S DISCS Sensitive to vibration & movement Found in stratum basale ROOT HAIR PLEXUS Sensitive to hair movement

31 SKIN PRESSURE RECEPTORS MEISSNER’S CORPUSCLES Light touch – objects that brush the skin Dermis PACINIAN CORPUSCLES Heavy pressure Dermis/Subcutaneous layer

32 OTHER SKIN RECEPTORS THERMORECEPTORS KRAUSE CORPUSCLES Cold RUFFINI CORPUSCLES Heat PAIN RECEPTORS Free nerve endings

33 Hyperhidrosis Overactive sweat glands Hands Feet Armpits Caused by overactive nervous system Treatment: Antiperspirant Iontophoresis Botox injections

34 The Skin’s Role in Homeostasis Vital in maintaining proper body temperature Important in the healing of wounds Aids in production of Vitamin D

35 VITAMIN D PRODUCTION Skin cells help produce vitamin D Dehydrocholesterol made by cells in digestive system Reaches skin and is changed to vitamin D when exposed to UV light

36 Regulation of Body Temp During intense heat, nerve impulses signals the body to release heat Blood vessels dilate, giving off heat through skin Eccrine sweat glands become active Sweat evaporates cooling skin

37 Regulation of Body Temp If too much heat is lost: Muscles in dermal wall contract Decreases blood flow and heat loss Sweat glands inactive Skeletal muscles contract involuntarily Release heat “Shivering”

38 Healing of Wounds INFLAMMATION – wound and surrounding areas become swelled Response to injury & stress 4 signs of inflammation: Redness Warmth Swelling Pain

39 Inflammation Redness - caused by increased vasodilatation More blood in area Heat – increased metabolism; WBC’s try to destroy invaders

40 Inflammation Swelling – Fluid in area due to change in osmotic pressure Abnormal build up of fluid called EDEMA Pain –Pressure on nerve endings from fluid

41 Healing of Wounds Shallow wounds (epidermis) Epithelial cells divide and fill in gap

42 Healing of Wounds Deep wounds (dermis or subcutaneous layer) Blood vessels broken Clot forms and dries into a scab Fibroblasts lay down collagen fibers forming scar Phagocytes remove foreign particles


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