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Copyright © 2010 Pearson Education, Inc.
Figure 5.1 Skin structure.
Epidermis
Hair shaft
Dermis Reticularlayer
Papillarylayer
Hypodermis(superficial fascia)
Dermal papillae
Pore
Subpapillaryvascular plexus
Appendagesof skin • Eccrine sweat gland• Arrector pili muscle• Sebaceous (oil) gland• Hair follicle• Hair rootNervous structures
• Sensory nerve fiber• Pacinian corpuscle• Hair follicle receptor (root hair plexus)
Cutaneous vascularplexus
Adipose tissue
Copyright © 2010 Pearson Education, Inc.
Figure 5.2 The main structural features of the skin epidermis.
Melanocyte
Melanin granule
Tactile(Merkel)cellSensorynerve ending
Epidermaldendritic cell
Dermis
Dermis
Keratinocytes
Desmosomes
(b)
(a)
Stratum corneumMost superficial layer; 20–30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space.
Stratum granulosumThree to five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellated gran-ules (release lipids) and keratohyaline granules.
Stratum spinosumSeveral layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin.
Stratum basaleDeepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. See occasional melanocytes and epidermal dendritic cells.
Copyright © 2010 Pearson Education, Inc.
Figure 5.2a The main structural features of the skin epidermis.
Dermis
Stratum corneumMost superficial layer; 20–30 layers of deadcells represented only by flat membranoussacs filled with keratin. Glycolipids inextracellular space.
Stratum granulosumThree to five layers of flattened cells,organelles deteriorating; cytoplasm full oflamellated granules (release lipids) andkeratohyaline granules.
Stratum spinosumSeveral layers of keratinocytes unified bydesmosomes. Cells contain thick bundles ofintermediate filaments made of pre-keratin.
Stratum basaleDeepest epidermal layer; one row of activelymitotic stem cells; some newly formed cellsbecome part of the more superficial layers.See occasional melanocytes and epidermaldendritic cells.(a)
Copyright © 2010 Pearson Education, Inc.
Figure 5.2b The main structural features of the skin epidermis.
MelanocyteMelanin granule
Tactile(Merkel) cell
Sensorynerve ending Epidermal
dendritic cell
Dermis
KeratinocytesStratum corneumMost superficial layer; 20–30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space.
Stratum granulosumThree to five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellated granules (release lipids) and keratohyaline granules.
Stratum spinosumSeveral layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin.
Stratum basaleDeepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. See occasional melanocytes and epidermal dendritic cells.
Desmosomes
(b)
Copyright © 2010 Pearson Education, Inc.
Figure 5.3 The two regions of the dermis.
Dermis
(a) Light micrograph of thick skin identifying the extent of the dermis, (50x)
(b) Papillary layer of dermis, SEM (22,700x)
(c) Reticular layer of dermis, SEM (38,500x)
Copyright © 2010 Pearson Education, Inc.
Figure 5.3a The two regions of the dermis.
Dermis
(a) Light micrograph of thick skin identifying the extent of the dermis, (50x)
Copyright © 2010 Pearson Education, Inc.
Figure 5.3b The two regions of the dermis.
Copyright © 2010 Pearson Education, Inc.
Figure 5.3c The two regions of the dermis.
Copyright © 2010 Pearson Education, Inc.
Figure 5.4 Dermal modifications result in characteristic skin markings.
Friction ridges
(a)
(b)
Openings ofsweat gland ducts
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Figure 5.5 Cutaneous glands.
(a) Photomicrograph of a sectioned sebaceous gland (220x)
(b) Photomicrograph of a sectioned eccrine gland (220x)
Sebaceousgland duct
Hair inhair follicle
Secretory cells
Dermalconnectivetissue
Dermalconnectivetissue
Duct
Sebaceousgland
Sweat pore
Eccrinegland
Copyright © 2010 Pearson Education, Inc.
Figure 5.5a Cutaneous glands.
(a) Photomicrograph of a sectioned sebaceous gland (220x)
Sebaceousgland ductHair inhair follicleSecretory cells
Dermalconnectivetissue
Sebaceousgland
Sweatpore
Eccrinegland
Copyright © 2010 Pearson Education, Inc.
Figure 5.5b Cutaneous glands.
(b) Photomicrograph of a sectioned eccrine gland (220x)
Secretory cells
Dermal connectivetissue
DuctSebaceousgland
Sweat pore
Eccrinegland
Copyright © 2010 Pearson Education, Inc.
Figure 5.6a Structure of a hair and hair follicle.
Hair shaft
ArrectorpiliSebaceousglandHair root
Hair bulb
(a) Diagram of a cross section of a hair within its follicle
• Connective tissue root sheath• Glassy membrane• External epithelial root sheath• Internal epithelial root sheath
Follicle wall
• Cuticle• Cortex• Medulla
Hair
Copyright © 2010 Pearson Education, Inc.
Figure 5.6b Structure of a hair and hair follicle.
(b) Photomicrograph of a cross section of a hair and hair follicle (250x)
• Connective tissue root sheath
Follicle wall
• Cuticle
• Glassy membrane
• Cortex• Medulla
• Internal epithelial root sheath
• External epithelial root sheath
Hair
Hair shaft
ArrectorpiliSebaceousglandHair root
Hair bulb
Copyright © 2010 Pearson Education, Inc.
Hair shaft
ArrectorpiliSebaceousglandHair root Hair bulb
(c) Diagram of a longitudinal view of the expanded hairbulb of the follicle, which encloses the matrix
• Internal epithelial root sheath• External epithelial root sheath
• Connective tissue root sheathFollicle wall
Hair matrix
MelanocyteHair papilla
Subcutaneous adipose tissue
• Medulla• Cortex• Cuticle
• Glassy membrane
Hair root
Figure 5.6c Structure of a hair and hair follicle.
Copyright © 2010 Pearson Education, Inc.
Figure 5.6d Structure of a hair and hair follicle.
(d) Photomicrograph of longitudinal view of the hair bulb in the follicle (160x)
Follicle wall
Hair matrix
Hair papilla
Subcutaneousadipose tissue
Hair root
• Connective tissue root sheath• Glassy membrane• External epithelial root sheath• Internal epithelial root sheath
• Cuticle• Cortex• Medulla
Hair shaft
ArrectorpiliSebaceousglandHair root
Hair bulb
Copyright © 2010 Pearson Education, Inc.
Figure 5.7 Structure of a nail.
Lateralnail fold
Lunule
Nailmatrix
Root of nail
Proximalnail fold
Hyponychium
Nail bed
Phalanx (bone of fingertip)
Eponychium(cuticle)
Bodyof nail
Free edgeof nail
(a)
(b)
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Figure 5.8 Photographs of skin cancers.
Copyright © 2010 Pearson Education, Inc.
Figure 5.9 Estimating the extent and severity of burns using the rule of nines.
Anterior and posteriorhead and neck, 9%
41/2%41/2%
Anterior and posteriorupper limbs, 18%
Anterior and posteriorlower limbs, 36%
100%
Totals
Anterior and posteriortrunk, 36%
Anteriortrunk,18%
9% 9%(Perineum, 1%)
41/2%
Copyright © 2010 Pearson Education, Inc.
Figure 5.10 Partial thickness and full thickness burns.
(a) Skin bearing partialthickness burn (1st and 2nd degree burns)
(b) Skin bearing fullthickness burn(3rd degree burn)
1st degreeburn
2nd degreeburn
3rddegreeburn
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Making Connections 5.1 Homeostatic Interrelationships Between the Integumentary System and Other Body Systems