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The Integumentary System

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

1 The Integumentary System
Chapter 5

2 Integumentary System The Body Covering Includes: skin, nails & hairs
Skin = cutaneous membrane

3 Structure Two main parts = Epidermis- surface epithelial layer
Dermis -deeper connective tissue layer Deep dermis not part of the skin = subcutaneous layer or Hypodermis

4 Figure 5.1

5 Epidermis Keratinized stratified squamous epithelium 4 cell types:
Keratinocytes Melanocytes Langerhans cells Merkel cells

6 Epidermal Cells Keratinocytes 90% of epidermal cells 4-5 layers
Produce keratin Protect skin Waterproof skin

7 Epidermal Cells Melanocytes - produce melanin
Transfer pigment to keratinocytes 8% of epidermal cells

8 Epidermal Cells Langerhans Cells- immune response
Merkel cells – sensory Include tactile disc and neuron = touch sensation

9 Epidermal Layers Generally 4 strata (layers)
Stratum basale –includes stem cells Stratum spinosum – 8-10 cell layer Cells beginning to look flattened Stratum granulosum –keratin Losing cell organelles and nuclei Include lamellar granules = waterproofing lipid Stratum corneum – flattened dead cells Cells shed and are replaced from below- mostly keratin-filled

10 Skin Color Melanin- dark color Carotene- yellow orange
Darkness depends on amount of melanin produced. gives some protection against UV Carotene- yellow orange In stratum corneum and adipose layers- Hemoglobin in blood- pink-red Depends on blood flow

11 Accessory Structures Hair Skin glands Nails

12 Hair Found on most skin surfaces Made of fused keratinized cells
Not on palmar surfaces of hand and fingers or plantar surfaces of feet Made of fused keratinized cells Consists of shaft & root Surrounded by hair follicle Base is bulb which includes growing matrix producing cells Nerves- hair root plexuses Muscle- arrector pili

13 Figure 5.3

14 Glands sebaceous gland- secrete oily sebum sudoriferous or sweat gland
Connected to hair follicles sudoriferous or sweat gland Eccrine sweat gland Wide distribution- thermoregulation apocrine sweat gland Axilla, groin, areolae, beard Contain other cell material and produce pheromes Ceruminous Glands- external auditory canal Combine with sebum to produce earwax

15 Nails Plates of packed hard dead keratinized cells
Nail body- major visible portion Free edge- part extending past finger or toe Root – part not visible

16 Figure 5.4a

17 Figure 5.4b

18 Functions Temperature Regulation Protection Sensory reception
Excretion & Absorption -small Vitamin D synthesis

19 Aging Adolescence- can develop acne Mostly dermis- visible ~ age 40
Loss of collagen fibers Loss of elasticity Loss of immune responses Decreased melanocyte functions- gray hair, blotches Thinning

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