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Chapter 5 The Integumentary System

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Presentation on theme: "Chapter 5 The Integumentary System"— Presentation transcript:

1 Chapter 5 The Integumentary System
Copyright 2010, John Wiley & Sons, Inc.

2 Copyright 2010, John Wiley & Sons, Inc.
Integumentary System The body’s covering Includes: skin, nails, and hairs Skin: cutaneous membrane Copyright 2010, John Wiley & Sons, Inc.

3 Copyright 2010, John Wiley & Sons, Inc.
Structure Two main parts Epidermis - surface epithelial layer Dermis - deeper connective tissue layer Subcutaneous (subQ) layer or hypodermis lies deep to dermis; is not part of the skin Copyright 2010, John Wiley & Sons, Inc.

4 Copyright 2010, John Wiley & Sons, Inc.
Integumentary System Copyright 2010, John Wiley & Sons, Inc.

5 Copyright 2010, John Wiley & Sons, Inc.
Epidermis Keratinized stratified squamous epithelium Cell types (4): Keratinocytes Melanocytes Langerhans cells Merkel cells Copyright 2010, John Wiley & Sons, Inc.

6 Copyright 2010, John Wiley & Sons, Inc.
Epidermal Cells Keratinocytes 90% of epidermal cells 4-5 layers Produce keratin Protects skin Waterproofs skin Copyright 2010, John Wiley & Sons, Inc.

7 Copyright 2010, John Wiley & Sons, Inc.
Epidermal Cells Melanocytes Produce melanin that gives color to skin, hairs Transfer pigment to keratinocytes Make up 8% of epidermal cells Copyright 2010, John Wiley & Sons, Inc.

8 Copyright 2010, John Wiley & Sons, Inc.
Langerhans cells Immune response Merkel cells Sense of touch Consist of tactile disc and neuron for touch sensation Free nerve ending Copyright 2010, John Wiley & Sons, Inc.

9 Copyright 2010, John Wiley & Sons, Inc.
Epidermal Layers Four Layers (strata) Stratum basale Includes stem cells; new cells arise here Stratum spinosum: 8-10 cell layer Cells beginning to look flattened Stratum granulosum makes keratin Losing cell organelles and nuclei Have waterproofing lipid Stratum corneum: flattened dead cells Cells here consist mostly of keratin. Cells here are shed and replaced from below. Copyright 2010, John Wiley & Sons, Inc.

10 Copyright 2010, John Wiley & Sons, Inc.
Skin Color Melanin: dark color Darkness depends on amount of melanin produced. Provides some protection against UV rays Carotene: yellow orange In stratum corneum and adipose layers- Copyright 2010, John Wiley & Sons, Inc.

11 Copyright 2010, John Wiley & Sons, Inc.
Skin Color Genetic Factors Amount of melanin – determined by DNA varying size of melanin granules albinos lack melanin Physiological Factors – affect skin color but not melanin production Hemoglobin in dermal blood vessels = pink Lack of hemoglobin in dermal blood vessels = blue (cyanosis) Inability to breakdown hemoglobin (liver problems) = jaundice - yellow Environmental Factors UV rays chemicals Drugs (antihistamines & antibiotics) Copyright 2010, John Wiley & Sons, Inc. 6-14

12 Copyright 2010, John Wiley & Sons, Inc.
Dermis binds epidermis to underlying tissues smooth muscle cells nerve cell processes blood vessels hair follicles glands – sweat & sebaceous Copyright 2010, John Wiley & Sons, Inc. 6-6

13 Dermis: 2 distinct layers
Papillary Layer – 20% below epidermis Loose areolar CT Surface forms dermal papillae (fingerprints) Meissner’s Corpuscles Reticular layer – 80% dense irregular CT Bundles of collagen, elastic, & reticular fibers Strength & resiliency Pacinina corpuscles Copyright 2010, John Wiley & Sons, Inc.

14 Copyright 2010, John Wiley & Sons, Inc.
Cutaneous Sensation Light touch detection – Meissner’s Corpuscle’s Egg-shaped Located in dermal papillae Fingertips, palms, soles, eyelids, tip of tongue, nipples, clitoris, tip of penis Pressure detection – Pacinian Corpuscle’s Onion-shaped Located in deep dermis and subcutaneous regions Copyright 2010, John Wiley & Sons, Inc.

15 Copyright 2010, John Wiley & Sons, Inc.
Dermis Main function = nourishment of epidermis Copyright 2010, John Wiley & Sons, Inc.

16 Copyright 2010, John Wiley & Sons, Inc.
Hair Found on most skin surfaces Not on palmar surfaces of hand and fingers or plantar surfaces of feet Made of fused keratinized cells Nerves in hair root plexuses Copyright 2010, John Wiley & Sons, Inc.

17 Copyright 2010, John Wiley & Sons, Inc.
Hair Follicles Copyright 2010, John Wiley & Sons, Inc. 6-8

18 Copyright 2010, John Wiley & Sons, Inc.
Hair Follicles Structure Root or base in deep dermis Follicle throughout dermis Hair shaft in epidermis Keratinization Cells in root = active mitosis Cells in follicle = maturing & accumulating keratin Cells in epidermis = dead epithelial cells; full of keratin = exposed hair or hair shaft Copyright 2010, John Wiley & Sons, Inc.

19 Copyright 2010, John Wiley & Sons, Inc.
Arrector Pili Muscle Bundle of smooth muscle associated with every hair follicle Causes hair to stand on end (“goose bumps”) when frightened or cold Copyright 2010, John Wiley & Sons, Inc.

20 Copyright 2010, John Wiley & Sons, Inc.
Hair Copyright 2010, John Wiley & Sons, Inc.

21 Copyright 2010, John Wiley & Sons, Inc.
Glands Sebaceous gland: secrete oily sebum Connected to hair follicles; keeps hair from drying out Disorders acne - hypersecretion of sebum; ducts clog & inflame seborrhea – hypersecretion of sebum; oily scales Sudoriferous (sweat) gland Merocrine/Eccrine sweat gland Wide distribution- thermoregulation Apocrine sweat gland Axilla, groin, areolae, beard Contain other cell material Ceruminous (wax) gland Modified apocrine gland Wax combines with sebum = earwax Copyright 2010, John Wiley & Sons, Inc.

22 Merocrine (Eccrine) Glands
Structure Coil in deep dermis Duct in dermis Pore at surface Characteristics Respond to elevated T/exercise No odor in secretion Function throughout life Not associated with hair follicles Location: forehead, neck, back Secretion (merocrine) = water plus Salts & wastes (urea & uric acid) Copyright 2010, John Wiley & Sons, Inc.

23 Copyright 2010, John Wiley & Sons, Inc.
Apocrine Glands Structure: ducts terminate into hair follicles Characteristics Respond to stress/emotions Odor in secretion Begin to function at puberty & continue through life Location: armpits, groin Secretion (apocrine) = sweat plus Oil & cellular debris Copyright 2010, John Wiley & Sons, Inc.

24 Copyright 2010, John Wiley & Sons, Inc.
Nails nail plate nail bed lunula – active mitosis Functions Manipulation Protection of digit ends Copyright 2010, John Wiley & Sons, Inc. 6-9

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Nails Copyright 2010, John Wiley & Sons, Inc.

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Nails Copyright 2010, John Wiley & Sons, Inc.

27 Subcutaneous Layer = Adipose Tissue
also called hypodermis – beneath the skin function = insulation major blood vessels Copyright 2010, John Wiley & Sons, Inc. 6-7

28 Functions of Integumentary System
Temperature regulation Protection Sensory reception Excretion and absorption: small amounts Vitamin D synthesis Copyright 2010, John Wiley & Sons, Inc.

29 Copyright 2010, John Wiley & Sons, Inc.
Heat production & Loss Heat production is mostly a by-product of cellular metabolism Heat is maintained through Negative feedback Heat Loss is controlled by regulating dermal blood flow Vasodilation – increases dermal blood flow, which also increases heat loss Vasoconstriction – decreases dermal blood flow which decreases heat loss Copyright 2010, John Wiley & Sons, Inc.

30 Low body T require heat loss to be minimized
Hypothalamus signals for sweating to decrease & dermal vasoconstriction Usually brings the body T back to normal If body T remains low after above action Heat must be produced Shivering occurs & tiny muscle contractions involved produce heat Copyright 2010, John Wiley & Sons, Inc.

31 Problems in Temperature Regulation
Hyperthermia – abnormally high body temperature Two common causes Humid air decreases evaporation Air T exceeds body T, thus heat is gained not lost Hypothermia – abnormally low body temperature Very dangerous if core body T drops below 94 degrees F Limbs can withstand about 65 degrees F because they contain no vital organs Cause is intentional during some surgical procedures Copyright 2010, John Wiley & Sons, Inc. 6-13

32 Copyright 2010, John Wiley & Sons, Inc.
Hypothermia Copyright 2010, John Wiley & Sons, Inc.

33 Copyright 2010, John Wiley & Sons, Inc.
Protection Physical Barrier From water loss From injury From chemicals & microorganism growth Chemical barrier pH Prevents microorganism growth Biological barrier Langerhan’s cells (epidermis) Macrophages and mast cells (dermis) Copyright 2010, John Wiley & Sons, Inc.

34 Copyright 2010, John Wiley & Sons, Inc.
Excretion Minimal, most through kidneys Urea Uric acid Copyright 2010, John Wiley & Sons, Inc.

35 Copyright 2010, John Wiley & Sons, Inc.
Vitamin D Synthesis UV rays in sunlight activate its synthesis Vitamin D is required for bone homeostasis Copyright 2010, John Wiley & Sons, Inc.

36 Copyright 2010, John Wiley & Sons, Inc.
Blood Reservoir The dermis houses about 10% of the body’s blood vessels Skin only requires 1-2% of the body’s blood Copyright 2010, John Wiley & Sons, Inc.

37 Copyright 2010, John Wiley & Sons, Inc.
Immunity Langerhan’s cells (macrophages) Interact with T-helper cells in immune responses Copyright 2010, John Wiley & Sons, Inc.

38 Healing of Wounds & Burns
Inflammation – process that involves blood flow changes & chemical signaling leading to healing Cuts: Epidermal cuts – closed by increased cell division in the stratum basale Deep cuts involve blood vessel damage resulting in Inflammation Blood clotting Scab formation Fibroblast infiltration & repair Scab falls off Scar may or may not remain Copyright 2010, John Wiley & Sons, Inc.

39 Copyright 2010, John Wiley & Sons, Inc.
Healing of Burns First degree burn – superficial partial-thickness Epidermis only Reddening due to increased blood flow Mild pain Common in sunburn Heals in a few days – 2 weeks Second degree burn – deep partial-thickness Epidermis & some dermal damage Reddening & blistering caused by blood vessel damage Moderate pain Common to physical contact with hot objects Heals in 2-6 weeks without scars unless infected Copyright 2010, John Wiley & Sons, Inc. 6-16

40 Third degree burn – full-thickness
Epidermis, entire dermis, & potentially subcutaneal damage Dry, leathery tissue with red or black color Severe pain Caused by prolonged heat or chemical contact Healing rarely occurs due to lack of surviving skin cells, skin replacements (grafts) are usually needed autograft – transplant form undamaged area of yourself homograft - temporary transplant from cadaver various skin substitutes extensive scars Copyright 2010, John Wiley & Sons, Inc.

41 Healing of Wounds & Burns
Burns - Body surface affected Estimated by “rule of nines” Important for determining treatment & prognosis Copyright 2010, John Wiley & Sons, Inc.

42 Copyright 2010, John Wiley & Sons, Inc.
Rule of Nines Copyright 2010, John Wiley & Sons, Inc. 6-17

43 Copyright 2010, John Wiley & Sons, Inc.
Aging Adolescence: can develop acne Visible signs of aging by about age 40. These include: Loss of collagen fibers Loss of elasticity Loss of immune responses Decreased melanocyte functions: gray hair, skin blotches Thinning of skin and hairs Copyright 2010, John Wiley & Sons, Inc.

44 Copyright 2010, John Wiley & Sons, Inc.
Clinical Application Acne Vulgaris most common skin disorder sebum and epithelial cells clog glands produces whiteheads and blackheads (comedones) anaerobic bacteria trigger inflammation (pimple) largely hormonally induced androgens stimulate sebum production treatments include antibiotics, topical creams, birth control pills Copyright 2010, John Wiley & Sons, Inc. 6-19

45 Copyright 2010, John Wiley & Sons, Inc.
Skin Cancer - ABCD Copyright 2010, John Wiley & Sons, Inc.

46 Copyright 2010, John Wiley & Sons, Inc.
End of Chapter 5 Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein. Copyright 2010, John Wiley & Sons, Inc.


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