8/7/2019 070809 Integumentary System

1/3

COURSE: ANATOMYTOPIC:INTEGUMENTARYSYSTEM

DATE: July 7,2009MED 2013 Sec B

SKIN- heaviest organ (16% of total body weight)

FUNCTION OF SKIN1. PROTECTION2. SENSATION3. THERMOREGULATION4. METABOLIC FUNCTION synthesis of vitamin B35. SEXUAL ATTRACTANT ie. Whitening,

dermatology6. LEGAL ie. Finger imprint

I.

I.

I.

I.

I.

I.

I.

I.

I.

I.

I.

I.

I.

LAYERS OF THE SKIN

1. EPIDERMIS- Epithelium from ectoderm- Ridges/ rete ridges- Superficial part of the skin- Stratified squamous keratinized

epitheleum

Layers of the Epidermisa. Stratum basale / germinativum

Single layer of columnar or cuboidalcells resting on basement membrane

Stem cells: in intense mitosis risesduring evening only

Epithelial cells regenerate q15 - 30days

Desmosomes binds lateral and uppersurfaces of the cell

Hemidesmosomes found in basalplasmalemma, help bind cells of thedermis to basal lamina

b. Stratum spinosum

Several layers of columnar topolygonal to slightly flattened cells

Desmosome (contains TONOFIBRILwhich is responsible for prickleappearance and maintaining cell

cohesion) Prickle cell layer

Ovoid nucleus with prominent nucleoli

Tonofilaments are keratin bundles w/c

play an important role in maintaining

cohesion among cells and resisting

effects of abrasions

Consists of cuboidal and slightly

flattened cells w/ central nucleus and

cytoplasm

c. Stratum granulosum

Three to five layers of flattened

cells Keratohyaline granules: basophilicgranules without membrane

Lamellar granules

membrane coated, made up bilipiclayer, barriers versus penetration

discharge as intracellular cementcohesion and resistance

Lose their nucleus and dies

Consists of three to five layers offlattened polygonal cells whosecytoplasm is filled w/ Coarse basophilicgranules called keratohyaline granules

d. Stratum lucidum

Appear in the THICK SKIN

Eosinophilic cells

Organelles are not evident

Flat cells without nucleus or organelles

Made up of keratin

Desmosomes are sadjacent cells

Made up of keratinembedded in an el

Translucent and flanucleus or organel

e. Stratum corneum

15-30 layers of flat

Lightly keratinized

Tonofilaments pack

matrix by keratohy Horny cells are cell

fibrillar and amorphthickened plasma m

*Malpidian Layer = basale + s

Cells of the Epidermis1. Melanocytes

Beneath, between

Stratum basale + sMalpighi

Stratum Basale + s= Stem cell

Irregular cytoplasm

Ectodermal in origi

Produce melanin2. Langerhan Cells

Macrophage of the

Immunologic

Stratum spinosum,3. Keratinocyte

Makes most of the 4. Merkels cell

Difficult to see

Found in palm and

Granules in apical

Function: Sensory

2. DERMIS

Connective tissue from me

Supports the epidermis an

subcutaneous tissue

8/7/2019 070809 Integumentary System

2/3

Has many projections that intergidate with

projections

Determines the developmental pattern of

overlying epidermis

Rich supply of nerves

Also Contains:

- Hair Follicles

- Sweat Glands

- Sebaceous Glands

Composition of Basement Membrane

Basal Lamina found between the stratum

germinativum and papillary layer of the dermis

Lamina Reticularis underlying the basal lamina

Layers of the Dermis1. Papillary

- Dermal papillae interdigitate withdermal peg or ridges

- Loose connective tissue

- Superficial- Outer layer- Anchoring fibrils (they bind the dermis

to the epidermis)Composition:

- Fibroblasts- Mast Cells- Macrophages

- Leukocytes

2. Reticular- Dense irregular connective tissue

- Contain epidermal derivatives whichcontains network of blood and lymphaticvessels and nerves

- More fibers and fewer cells than papillarylayer

- Contains networks of fibers of elasticsystem which is responsible for elasticityof skin

* Boundary cell of epidermis and dermis: dermalpapillae and epidermal ridges* Lypodermis (LCT with adipose cells) superfiscial fascia

*not a part of the skin

Difference between THIN and THICK sKIN

Thin(hairy)coversentirebody

exceptpalms andsole of the

feet

Thickcoversonthe pals

and solesof feet

A.EPIDERMIS

Hair follicles

SweatGlands

Stratumlucidum

Stratumgranulosum

Stratumspinosum

B. DERMIS

PapillaeC. DERMOEPIDERMAL JX

Presentexcept inglanspenisFewerAbsentIndistinctthinThin

HaphazardsPeg andsocket

AbsentNumerousPresentDistinctlayerVeryThick

VeryThickregular

3. HYPODERMIS

-Subcutaneous tissue (panniculs adiposis)

- Lowermostt layer of integumentarysystem

Cells that can be found in Hyp- Fibroblasts- Adipose Cells- Macrophages

II. SKIN COLOR DEPENDS ON:1. Melanin fair versus d

of melanocytes2. Carotene3. Number of Blood vesse4. Color of Blood

Depigmentation disorders:o Albinism no ty

o Vitiligo degrag

melanocytes (iesickness of Mich

III. EPIDERMAL SKIN APPENDADERIVATIVES

First develop during 2n

intrauterine developm

1. HAIRo Hair follicle

dense connectiv

head, scapular

hair shafts (longstructures)

keratino Hair bulb

at the base

terminaldilatation(dermalpapillae)

o Dermal Papilla

Contains anetwork ofcapillaries

Found atthe base

Layers of Hairo Hair root

8/7/2019 070809 Integumentary System

3/3

surrounding cellso Medulla

Central part of hair shafto Hair cortex

Surrounds medullao Cuticle

periphery surrounding hair cortex

single layer of flattened scaleso Internal root sheath transient structure

o External root sheath all layers of

epidermiso Glassy membraneo Connective tissue sheath

arector pill - d/t depression of skin(goose flesh)

Dermal papillae hair bulb

2. NAIL- keratinized plates on dorsal surfaces of the tipsof the fingers and toes

- Nail Root- Proximal edge of plate- Nail Matrix- responsible for

growth of nails-- Nail plate

-s. Corneum

- Nail bed- str. Basale+str.

Spinosu- surface of skin

covered by nail- Nail fold- Surrounds nails- Overlapped by folds of skin (except

distal end of plate)- Lanula- distal portion of matrix

3. SEBACEOUS GLANDS- Morphological classification: simple,

branched, alveolar/acinar glandso Each acinar has lipid vacuoles

- Based on gland participation: halocrineglands = cell swell and secreted as sebum

- Multi-cellular- Sebum

o mixture of lipids secreted by

sebaceous glandso waterproofing of skin surface and

hair shafto preserves flexibility of emerging

hair

4. SWEAT GLANDS- Stratified cuboildal epithelium: sensory

portion of sweat glands- Serous, mucous- Reduces body temperature- Deeply penetrating structures of all

epidermal appendages- Found all throughout the body

o Eccrine/Merocrine

Simple duct

Innervated by cholinergicnerves

Dense cells, clear cells,myoepithelial cells

Particularly: palm, sole,forehead

All except lips, nails, penis

Secretory: dark, luminalsurface

Clear, no secretory granules

o Apocrine

Locatedaxillary perianal

Adrenerg

Large glsecrete follicle)

Discontimyoepiteccrine)

Thin EPIDERMIS Hair follicle Entire (+)

Except glapenis, clitolabia minolips

Sweat gland Str.

SpinosumThin

Str.Granulosum

Indistinct

Str.Lucidum

Absent

Str.Corneum

Thin

DERMISPapillae(invagination of dermis)

Haphazard

Dermo-epidermisjunction

Peg andSocket

References:Eroshenko, V. Di Fiores atlas of histo

correlations, 10th ed CD-ROM.Junquiera, L.C. & Carniero, J. Basic hi

atlas, 11th ed. USA: Mc Graw Hill

Snell, R.S. (2008). Clinical anatomy bUSA: Lippincott and Williams

Young, B., et al. (2006). Wheaters fuA text and colour atlas. Church Li