1 Integumentary System

Question of the Day What do you know about skin? 2

3 Purpose of system Regulates body temperature Storage of nutrients Protection Excretion/Secretion Sensations

Membranes Combinations of epithelial and connective tissues 4 Types Serous Mucous Synovial Cutaneous 4

5 Serous Membranes Lines cavities that lack opening to outside Inner lining of thorax and abdomen Covers organs within cavities Simple Squamous epithelium over a thin layer of loose connective tissue Secretes watery, serous fluid for lubrication

6 Mucous Membranes Lines cavities and tubes that open to outside Oral/Nasal cavity, tubes of digestive, respiratory, urinary, reproductive systems Epithelium tissue over loose connective tissue Secretes mucous via goblet cells

7 Synovial membranes Lining of joint cavities between ends of bone at free moving joints Fibrous Connective tissue over loose connective tissue and adipose tissue Secretes thick, colorless synovial fluid or lubrication

8 Cutaneous Membrane a.k.a Skin Two distinct layers (3 layers total) Epidermis Dermis Hypodermis (subcutaneous layer)

9 Epidermis Stratified squamous epithelium 5 layers of cells Stratum germinativum (basale) Epidermal ridges and melanocytes Stratum spinosum Stratum granulosum Stratum lucidum Keratin Stratum corneum

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Skin Color & Vitamin D Skin color is caused by pigment concentration and composition Carotene and Melanin dermal blood supply cyanosis Vitamin D Modified form of cholesterol altered to calcitriol for Ca and P absorption 11

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13 Dermis Binds epidermis to underlying tissues 2 major components Papillary Layer Loose CT, capillaries, nerves Reticular Layer Dense CT Accessory Structures

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15 Hypodermis Mainly composed of loose connective tissue and adipose tissue Insulation (conserves body heat) Major blood vessels

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Accessory Structures Include Hair Follicules Sebaceous Glands Sweat Glands Nails 17

Hair Follicles Located deep within the skin Cell division happens at the root Shaft forms as keratinization happens 18

19 Sebaceous (Oil) Glands Attached to hair follicle Holocrine glands oily mixture and sebum Soft, pliable, waterproof

20 Sweat Glands Widespread Deep in dermis or superficial subcutaneous layer 2 types of: Apocrine Only active when upset/puberty armpits, groin, hair follicles; Earwax Eccrine (Merocrine) Most abundant responds to elevated body temp. neck, forehead, back secretion via pore (sweat)

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Nails Keratinized cells 22

23 Wound Healing Inflammation normal response to injury or stress Blood vessels dilute Stimulates cell division Clotting, Scabs form…Scare tissue Affected by age, malnutrition, poor circulation, foreign bodies, infection, type of wound

Burns Exposure to heat, radiation, electrical shock, chemical agents 1 st degree Top layers of epidermis are destroyed 2 nd degree Epidermis and top layer of dermis are destroyed 3 rd degree Epidermis, dermis, and portion of hypodermis are destroyed 24

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27 Skin Cancers Carcinomas Most Common Epithelial Cells Slow growing Cured by removal and/or radiation treatment Often in fair-skinned, 40 year olds, regular exposure to light, some times due to apotosis Melanomas Melanocytes Irregular, bumpy shape; various colors (brown, black, blue, gray) Horizontal & Vertical growth Survival rate higher if removed in horizontal stage In all ages, due to short, intermittent exposure to high-intensity sunlight; can arises from moles

What can you do to reduce your risk of skin cancer? 28

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