5 The Integumentary System Power Point Lecture Presentations

I. The Skin and the Hypodermis A. skin - our largest organ B. accounts

Epidermis Dermis Hypodermis Deep fascia Muscle © 2014 Pearson Education, Inc.

Epidermis Papillary dermis Dermis Reticular dermis Hypodermis (superficial fascia) © 2014 Pearson Education, Inc.

II. Epidermis A. is composed of keratinized stratified squamous epithelium B. contains four main

2. melanocytes Location—basal layer; manufacture and secrete pigment 3. tactile epithelial cells Location—basal

II. Layers of the Epidermis deep surface ► stratum basale (stratum geminativum) ► stratum

A. Stratum basale (at the “base”) 1. deepest layer of epidermis 2. attached to

B. Stratum spinosum (“spiny” layer) 1. “spiny” appearance 2. contains thick bundles of intermediate

C. Stratum granulosum 1. consists of a few layers of keratinocytes a. keratinocytes contain:

E. Stratum corneum (“horny” layer) 1. only on thick layer of dead keratinocytes 2.

Stratum corneum Most superficial layer; 20– 30 layers of dead cells represented only by

III. Dermis A. Second major region of the skin B. Strong, flexible connective tissue

E. Papillary Dermis 1. dermal papillae a. more surface area ► exchange gases, nutrients,

Hair shaft Dermal papillae Epidermis Papillary dermis Dermis Reticular dermis Hypodermis (superficial fascia) Adipose

Openings of sweat gland ducts Friction ridges Flexure lines on digit Friction ridges of

F. Reticular Dermis 1. accounts for 80% of dermal thickness 2. dense irregular connective

Flexure lines on digit Flexure lines on the palm Flexure lines of the hand

G. Hypodermis - deep to the skin 1. also called superficial fascia 2. contains

Hair shaft Epidermis Papillary dermis Dermis Reticular dermis Hypodermis (superficial fascia) Adipose tissue ©

IV. Skin Color A. Two pigments contribute to skin color 1. melanin - most

V. Nails A. Nails – scale-like modification of epidermis; hard keratin 1. free edge

Lunule Free edge of nail © 2014 Pearson Education, Inc. Lateral nail fold Nail

Free edge of nail Nail root Eponychium (cuticle) Nail Proximal plate nail fold Nail

B. Hair 1. flexible strand of dead, keratinized cells 2. hard keratin - tough

Hair shaft Epidermis Papillary dermis Dermis Reticular dermis Hypodermis (superficial fascia) © 2014 Pearson

Hair shaft Arrector pili Sebaceous gland Hair root Follicle wall Peripheral connective tissue (fibrous)

Follicle wall Peripheral connective tissue (fibrous) sheath Glassy membrane Epithelial root sheath External root

Hair shaft Follicle wall Glassy membrane Arrector pili Peripheral connective tissue (fibrous) sheath Epithelial

VI. Appendages of the Skin A. wall of hair follicle B. connective tissue root

VII. Types and Growth of Hair A. vellus hairs - body hairs of women

VIII. Sebaceous Glands A. occur over entire body (except palms and soles) B. secrete

IX. Sweat Glands A. (sudoriferous glands) - widely distributed on body B. sweat -

C. Two types of sweat gland 1. eccrine gland (merocrine) - produce true sweat

Epidermis Papillary dermis Dermis Sweat pore Appendages of skin Eccrine sweat gland Arrector pili

X. Burns A. classified by severity 1. first-degree burn - only upper epidermis is

Anterior values 1 st degree burn Totals 4½% Anterior and posterior head and neck,

XI. Skin Cancer A. basal cell carcinoma - least malignant and most common B.

Basal cell carcinoma © 2014 Pearson Education, Inc. Squamous cell carcinoma Melanoma

Slides: 43

Download presentation

I. The Skin and the Hypodermis A. skin - our largest organ B. accounts for 7% of body weight C. varies in thickness from 1. 5 to 4. 4 mm D. divided into two distinct layers 1. epidermis 2. dermis a. hypodermis - lies deep to the dermis b. composed of areolar and adipose tissues © 2014 Pearson Education, Inc.

II. Epidermis A. is composed of keratinized stratified squamous epithelium B. contains four main cell types: 1. keratinocytes Location—stratum spinosum; produce keratin, a fibrous protein a. arise from deepest layer of epidermis b. produce keratin, a tough fibrous protein c. produce antibiotics and enzymes d. keratinocytes are dead at skin’s surface © 2014 Pearson Education, Inc.

2. melanocytes Location—basal layer; manufacture and secrete pigment 3. tactile epithelial cells Location—basal layer; attached to sensory nerve endings 4. dendritic cells Location—stratum spinosum; macrophage-like © 2014 Pearson Education, Inc.

II. Layers of the Epidermis deep surface ► stratum basale (stratum geminativum) ► stratum spinosum ► stratum granulosum ► stratum lucidum (***only in thick skin***) ► stratum corneum © 2014 Pearson Education, Inc.

A. Stratum basale (at the “base”) 1. deepest layer of epidermis 2. attached to underlying dermis 3. cells actively divide by mitosis 4. contains: a. tactile epithelial cells—associated with sensory nerve b. melanocytes—secrete the pigment melanin © 2014 Pearson Education, Inc.

B. Stratum spinosum (“spiny” layer) 1. “spiny” appearance 2. contains thick bundles of intermediate filaments 3. resist tension and contain the protein pre-keratin 4. among the keratinocytes are star-shaped dendritic cells a. are a type of macrophage b. function in immune system © 2014 Pearson Education, Inc.

C. Stratum granulosum 1. consists of a few layers of keratinocytes a. keratinocytes contain: ► keratohyaline granules—help form keratin ► lamellar granules—contain waterproofing glycolipid D. Stratum lucidum (“clear” layer) 1. occurs only in thick skin 2. locations of thick skin—palms and soles 3. composed of a few rows of flat, dead keratinocytes © 2014 Pearson Education, Inc.

E. Stratum corneum (“horny” layer) 1. only on thick layer of dead keratinocytes 2. composed of a few rows of flat, dead keratinocytes 3. protects skin against abrasion and penetration © 2014 Pearson Education, Inc.

Stratum corneum Most superficial layer; 20– 30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space. Stratum granulosum One to five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellar granules (release lipids) and keratohyaline granules. Stratum spinosum Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin. Desmosomes Stratum basale Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. See occasional melanocytes and dendritic cells. Dermis © 2014 Pearson Education, Inc.

Stratum corneum Most superficial layer; 20– 30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space. Keratinocytes Stratum granulosum One to five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellar granules (release lipids) and keratohyaline granules. Stratum spinosum Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin. Desmosomes Stratum basale Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. See occasional melanocytes and dendritic cells. Dermis Dendritic cell Sensory Melanocyte Melanin nerve Tactile granule ending epithelial cell © 2014 Pearson Education, Inc.

III. Dermis A. Second major region of the skin B. Strong, flexible connective tissue C. Richly supplied with blood vessels and nerves D. Has two layers: 1. Papillary dermis (layer)—includes dermal papillae 2. Reticular dermis (layer) - deeper layer— 80% of thickness © 2014 Pearson Education, Inc.

E. Papillary Dermis 1. dermal papillae a. more surface area ► exchange gases, nutrients, and wastes b. lie on dermal ridges 2. epidermal ridges (friction ridges) a. elevations of dermal ridges b. fingerprints - increase gripping ability of hands and feet © 2014 Pearson Education, Inc.

Openings of sweat gland ducts Friction ridges Flexure lines on digit Friction ridges of fingertip (SEM 12 ) Flexure lines on the palm Cleavage lines in the reticular dermis © 2014 Pearson Education, Inc. Flexure lines of the hand

F. Reticular Dermis 1. accounts for 80% of dermal thickness 2. dense irregular connective tissue 3. cleavage lines - separation between collagen fibers 4. flexure lines - deep creases in palms and fingers 5. important role in temperature regulation © 2014 Pearson Education, Inc.

G. Hypodermis - deep to the skin 1. also called superficial fascia 2. contains areolar and adipose connective tissue 3. anchors skin to underlying structures 4. helps insulate the body 5. has different distribution in males and females © 2014 Pearson Education, Inc.

IV. Skin Color A. Two pigments contribute to skin color 1. melanin - most important pigment—made from tyrosine 2. carotene - yellowish pigment from carrots and tomatoes 3. caucasian skin contains little melanin © 2014 Pearson Education, Inc.

B. Hair 1. flexible strand of dead, keratinized cells 2. hard keratin - tough and durable 3. root - embedded in the skin 4. shaft - projects above skin’s surface a. hair has three concentric layers of keratinized cells i. medulla - central core ii. cortex - surrounds medulla iii. cuticle - outermost layer C. hair follicles - extend from epidermis into dermis © 2014 Pearson Education, Inc.

Hair shaft Arrector pili Sebaceous gland Hair root Follicle wall Peripheral connective tissue (fibrous) sheath Glassy membrane Hair bulb Epithelial root sheath External root sheath Internal root sheath Hair Cuticle Cortex Medulla Diagram of a cross section of a hair within its follicle © 2014 Pearson Education, Inc.

Follicle wall Peripheral connective tissue (fibrous) sheath Glassy membrane Epithelial root sheath External root sheath Internal root sheath Hair Cuticle Cortex Medulla Photomicrograph of a cross section of a hair and hair follicle (120 ) © 2014 Pearson Education, Inc.

Hair shaft Follicle wall Glassy membrane Arrector pili Peripheral connective tissue (fibrous) sheath Epithelial root sheath External root sheath Internal root sheath Sebaceous gland Hair root Cuticle Cortex Medulla Hair root Hair bulb Hair matrix Dermal papilla Melanocyte Subcutaneous adipose tissue Diagram of a longitudinal view of the expanded hair bulb of the follicle, which encloses the matrix © 2014 Pearson Education, Inc.

VI. Appendages of the Skin A. wall of hair follicle B. connective tissue root sheath C. epithelial tissue root sheath D. Arrector pili muscle - bundle of smooth muscle 1. hair stands erect when arrector pili contracts © 2014 Pearson Education, Inc.

VII. Types and Growth of Hair A. vellus hairs - body hairs of women and children B. terminal hairs 1. hair of scalp 2. axillary and pubic area (at puberty) 3. hair thinning and baldness due to aging 4. male pattern baldness © 2014 Pearson Education, Inc.

VIII. Sebaceous Glands A. occur over entire body (except palms and soles) B. secrete sebum 1. an oily substance 2. Collects dirt 3. softens and lubricates hair and skin C. simple alveolar glands D. most are associated with a hair follicle 1. holocrine secretion - entire cell breaks up to form secretion © 2014 Pearson Education, Inc.

IX. Sweat Glands A. (sudoriferous glands) - widely distributed on body B. sweat - is a blood filtrate 1. 99% water with some salts 2. Contains traces of metabolic wastes 3. about 2% urea © 2014 Pearson Education, Inc.

C. Two types of sweat gland 1. eccrine gland (merocrine) - produce true sweat 2. apocrine gland a. confined to axillary, anal, and genital areas b. produce a special kind of sweat c. musky odor—attracts a mate d. ceruminous glands (ear wax) and mammary glands © 2014 Pearson Education, Inc.

Epidermis Papillary dermis Dermis Sweat pore Appendages of skin Eccrine sweat gland Arrector pili muscle Sebaceous (oil) gland Hair follicle Hair root Reticular dermis Hypodermis (superficial fascia) Adipose tissue © 2014 Pearson Education, Inc.

X. Burns A. classified by severity 1. first-degree burn - only upper epidermis is damaged 2. second-degree burn - upper part of dermis is also damaged a. blisters appear b. skin heals with little scarring 3. third-degree burn a. consumes thickness of skin b. burned area appears white, red, or blackened B. The Rule of Nines © 2014 Pearson Education, Inc.

Anterior values 1 st degree burn Totals 4½% Anterior and posterior head and neck, 9% Anterior and posterior upper limbs, 18% 2 nd degree burn Skin bearing partial-thickness burn (first- and second-degree burn) 3 rd degree burn 4½% Anterior and posterior trunk, 36% Anterior trunk, 18% 9% 9% (Perineum, 1%) Anterior and posterior lower limbs, 36% Skin bearing full-thickness burn (third-degree burn) © 2014 Pearson Education, Inc. 100% Rule of nines; used to estimate extent of burns

XI. Skin Cancer A. basal cell carcinoma - least malignant and most common B. squamous cell carcinoma - arises from keratinocytes C. melanoma - A cancer of melanocytes; most dangerous type © 2014 Pearson Education, Inc.