Lecture Human anatomy and physiology - Chapter 5: The integumentary system

Would you be enticed by an ad for a coat that is waterproof, stretchable, washable, and permanent-press, that automatically repairs small cuts, rips, and burns? How about one that’s guaranteed to last a lifetime? Sounds too good to be true, but you already have such a coat-your skin. The skin and its derivatives (sweat and oil glands, hairs, and nails) make up a complex set of organs that serves several functions, mostly protective. Together, these organs form the integumentary system.
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Lecture Human anatomy and physiology - Chapter 5: The integumentary system PowerPoint® Lecture Slides prepared by Janice Meeking, Mount Royal College CHAPTER 5 The Integumentary SystemCopyright © 2010 Pearson Education, Inc. Skin (Integument) • Consists of three major regions 1. Epidermis—superficial region 2. Dermis—middle region 3. Hypodermis (superficial fascia)—deepest region • Subcutaneous layer deep to skin (not technically part of skin) • Mostly adipose tissueCopyright © 2010 Pearson Education, Inc. Hair shaft Dermal papillae Epidermis Subpapillary Papillary vascular plexus layer Pore Appendages of skin Dermis Reticular • Eccrine sweat layer gland • Arrector pili muscle Hypodermis • Sebaceous (superficial fascia) (oil) gland • Hair follicle Nervous structures • Hair root • Sensory nerve fiber Cutaneous vascular • Pacinian corpuscle plexus • Hair follicle receptor Adipose tissue (root hair plexus)Copyright © 2010 Pearson Education, Inc. Figure 5.1 Epidermis • Keratinized stratified squamous epithelium • Cells of epidermis • Keratinocytes—produce fibrous protein keratin • Melanocytes • 10–25% of cells in lower epidermis • Produce pigment melanin • Epidermal dendritic (Langerhans) cells—macrophages that help activate immune system • Tactile (Merkel) cells—touch receptorsCopyright © 2010 Pearson Education, Inc. Stratum corneum Most superficial layer; 20–30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space. Stratum granulosum Three to five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellated granules (release lipids) and keratohyaline granules. Stratum spinosum Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin. Stratum basale Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. (a) See occasional melanocytes and epidermal Dermis dendritic cells.Copyright © 2010 Pearson Education, Inc. Figure 5.2a Layers of the Epidermis: Stratum Basale (Basal Layer) • Deepest epidermal layer firmly attached to the dermis • Single row of stem cells • Also called stratum germinativum: cells undergo rapid division • Journey from basal layer to surface • Takes 25–45 days ...