Integumentary System (Skin)

Integumentary System Structure: –Epidermis: Stratum corneum: dead cells, mostly keratin. Stratum lucidum: dead keratyoncytes; not present in all the skin. Stratum granulosum: –Lamelated granules (waterproofing) –Keratohyaline granules. Stratum spinosum: prekeratin. Stratum basale –Dermis Papilar layer Reticular layer Function –Protection Insulation Chemical damage Bacterial invasion Dehydration Temperature regulation –Secretory Urea, salts, water –Synthesis of vitamin D –Sensory

Figure 5.1

Cells in the Epidermis Keratynocytes –Produce keratin Melanocytes –Produce melanin pigment Langerham’s cells –Immunity Merkel cells –Touch receptors

Cells in the Dermis Meissner’s corpuscles –Papillary layer (areolar conective tissue): pain and touch receptor. Paccinian corpuscles –Reticular layer (dense irregular): pressure receptor.

Figure 5.2

"Cher Likes Getting Skin Botoxed" (from superficial to deep) "Before Signing, Get Legal Counsel" (from deep to superficial) "Before Sex Get Latex Condoms (from deep to superficial)

Figure 4.37

Accesory organs of the skin Nails Hair –Hair –Follicle –Arrector pilli muscle Cutaneous glands –Sebaceous: skin moisture. –Sweat Ecrine (merocrine sweat glands) temperature regulation through perspiration. Appocrine:axillary and genital area (fats, water, salts, urea): pheromones?

Figure 5.6 Nails

Figure 5.4

Figure 5.5a, b Hair (transverse view)

Figure 5.5c, d Hair follicle (longitudinal view)

Figure 5.3

Figure 5.3a

Figure 5.3b Sweat gland