Anatomy, Skin

Anatomic Model Of The Skin Frontal Section. The Integumentary System Includes The Skin And Its Appendages Hairs, Glands, Muscles And Nerves. The Skin Is Constituted By Two Tissue Layers, The Epidermis And The Dermis, Covering The Subcutaneous Tissue. The Epidermis, The Outermost Layer Of The Skin, Is A Stratified Pavimentous Epithelium. The Basal Layer In Deep Blue, The Deepest One, Is Constituted By Keratinocytes, Cells With A High Proliferation Rate And Producing Keratin, And Melanocytes Synthesizing Melanin Responsible For The Skin Color. As They Renew, The Keratinocytes Are Pushed Upward To Form Successively The Spinous And Granular Layers In Blue And Then The Horny Layer Of The Epidermis In Beige. The Latter Is Composed Of Dead Keratinocytes That Will Desquamate. Pores Open On The Epidermis Surface, At The End Of The Hair Shafts In Black And Of The Sweat Ducts In White. The Dermis In Pinkish Beige, The Inner Layer, Is A Fibrous Connective Tissue Conferring Skin Resistance And Elasticity. The Superficial Area Of The Dermis, The Papillary Dermis, Draws Ridges, The Papillae, That Increase Its Surface. They Include Loops Of Blood Capillaries Venous In Blue And Arterial In Red. . The Deeper Reticular Dermis Includes Hair Follicles, Blood Vessels, Sebaceous Glands In Mauve And Eccrine Sweat Glands In White, Responsible For The Perspiration. The Hair Is Constituted By Severeal Separate Areas: The Outer Shaft, The Root, Implanted In The Dermis, And The Bulb, Which Includes The Papilla White Bulge That Contains The Blood Supply And Feeds The Hair. An Hair Is Composed Of Several Concentric Cylindric Tissue Layers: The Medulla In The Center, In White, The Cortex In Black And Then The Cuticle In Yellow Forming The Hair Root. The Latter Is Surrounded By The Hair Follicle, A Cover Including An Epithelial Root Sheath With An Inner, In Azure, And A Outer Root Sheath, In Gray And (Photo By BSIP/UIG Via Getty Images)