ANATOMY AND PHYSIOLOGY OF THE SKIN

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INTRODUCTION

Skin :

- Body organ : site outer

- a complex organ that protect its host from environment, at the same time allowing interaction w/ the environment

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Skin : very complex, elastic & sensitive.

Variation according : climate, age, sex,

race & depend to location of the body.

The skin character’s : smooth, hard,

reguler/not thin, thick, strong attach with

the body nothing similarity.

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Skin can move & stretch depend

on:

Thick and the fold, elastisitasity

The skin attach with underlying

tissue

Skin elastic and loose : palpebra,

lip and preputium.

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Skin thick and not stretched

hand and feet

Skin thin face, that smooth

neck and the body, hard form

head Dermatochalasis

palmar and plantar

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Embriology of the skinEmbriology of the skin :

1. Ectoderm : epidermis

2. Mesoderm :

a. Dermis – corium – cutis

b. Subcutis

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Skin Appendage : Gland on the skin Apocrin Ecrin Sebacea Hair Muscle Nerve, blood vessel, lymphoid vessel

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Epidermis contain = ecrin gland, apocrin gland, sebaceus gland, hair and nail

Ecrin gland : 2-5 million , the most in palmar areaApocrin gland : location in armpit, anogenital,

areola mammaeSebaceus gland : all over the body, except

palmar, plantar and dorsum pedis. Lots of in scalp, face, forehead and chin

Hair: all over the body, except palmar, plantar, dorsal of distal phalangs fingers & toes, penis, labia minora, lips

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Anatomi based histopathology

The skin as large line, consist of 3 layer :

I. Epidermis layer / cutikel

II. Dermis layer / corium, cutis vera, true skin

III. Subcutis layer (hipodermis)

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Dermis and subcutis

characterized by connective tissue

(nothing big line) and present cell

and fat tissue

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1. Epidermis layer

Epidermis consist of 5 layer :

1.Stratum corneum (SC) ; complete differentiation of granular cells results in stacked layers of a nucleate, flattened cornified cells that form SC

Mechanical protection to the skin & a barrier to water loss & permeation of soluble substances from the environment

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2. Stratum Lucidum

1 layers. flattened cornified cells , no

nucleous

Protoplasma change protein eleidin

On the palmar and plantar pedis

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3. Stratum granulosum (Ganulosum layer)Basophilic keratohyalin granules that are

prominent within cellsKeratohyalin granules are compound primarily of

profilaggrin, keratin filaments, & loricrin4. Stratum spinosum (Spinosum layer)Spine-like appearanceSuprabasal spinous cell : polyhedral in shape

w/a rounded nucleusSpinous cells also contain large bundle of keratin

filaments

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5. Stratum Basale (BL) = (stratum germinativum)

Palisade form (columnar shaped Kc) Basal cell mitotically active Layers consist of 2 :1. Columnar cell2. Melanocytes

are neural crest-derived pigment-synthesizing dendritic cells that reside primarily in the BL

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2. Dermis Layer

Elastic dan fibrous layer with cellular element and hair follicle 2 part :

a. Stratum papillare to epidermis b. Stratum reticulare to subcutis, more

thick & connective tissue. Containing: nerve, blood vessel, hair, sweat gland n sebaceous gland

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3. Subcutis Layer

Adipocytes form the bulk of of the cells in the hypodermis.

organized into lobules defined by septa of fibrous

connective tissue

Nerves, vessels and lymphatics are located within the septa

& supply the region.

Two regions (Dermis & Subcutis) = structurally &

functionally integrated through networks of nerves &

vessels & the continuity of the epidermal appendages

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Phisiology of The Skin

Main function :

1. Protection from infectious agent

2. Ultraviolet protection

3. Perception

4. Regulatory body temperature (thermoregulation)

5. Respiration

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5. Excretion

6. Expression

7. Wound repair/regeneration

8. Forming precussor vitamin D

9. Physical appearence

10.Recently immunologic agent

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Transit time for a basal cell from the time it loses contact with the basal layer to the time it enters stratum corneum , is at least 14 days

Transit through the SC and subsequent desquamation require another 14 days

Thickness of epid from 0.4to 1.5 mm as compared with the 1.5 mm to 4.0 mm full thickness skin

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