Instructor Slides OpenStax_Ch5 Human Anatomy and Physiology 1 PDF

Human Anatomy and Physiology 1 (BIOL131) Chapter 5 - The Integumentary System  Learning Objectives 1. Be able to describe the gross anatomy and layers of the skin,the type of tissue each layer is made of: Layers of dermis and epidermis 2. Be able...

Human Anatomy and Physiology 1 (BIOL131) Chapter 5 - The Integumentary System  Learning Objectives 1. Be able to describe the gross anatomy and layers of the skin,the type of tissue each layer is made of: Layers of dermis and epidermis 2. Be able to describe the gross anatomy and layers of the skin,the type of tissue each layer is made of: Structure and function of subcutaneous layer 3. Be able to describe the gross anatomy and layers of the skin,the type of tissue each layer is made of: Difference between thick and thin skin 4. Which pigments are responsible for skin color, where are they produced, and which layers they are contained 5. Understand the general functions of the skin: What is its role in thermoregulation? 6. Understand the structure, location, and function of all accessory organs.: Hair 7. Understand the structure, location, and function of all accessory organs.: Arrector pilli musle 8. Understand the structure, location, and function of all accessory organs.: Glands (eccrine, apocrine, sebaceous) 9. Understand the general functions of the skin: How does it contribute to physical protection of the body? 10. Understand the general functions of the skin: What is its role in as a physical barrier to infection? 11. Understand the structure, location, and function of all accessory organs.: General sensory receptors 12. Understand the structure, location, and function of all accessory organs.: Describe degree and extent assessment of burns 13. Understand the structure, location, and function of all accessory organs.: Describe the three major types of skin cancer  Functions of the skin What are the function of the skin? (What does skin do for us?) – Protection – Excretion – Maintain body temperature – Sensation – vitamin D production  Terminology integument = skin = cutaneous membrane integumentary system = skin + accessory structures (hair, nails, skin glands) skin = epidermis (epithelia) + dermis (Connective Tissue) subcutaneous layer: separates skin from underlying organs LO 5.1, 5.2 List the general (major) components of the skin Epithelial tissue Connective tissue proper Hair Glands (sweat and oil) Muscles (arrector pili) Blood vessels Nervous tissue LO 5.1, 5.2, 5.11 Skin structure & function LO 5.1, 5.2 Skin structure & function LO 5.1  Epidermis Organization What is the primary tissue type found in the epidermis? Stratified squamous epithelium (keratinized) How many layers? More than one layer = stratified 4 or 5 layers/zones Where is the thickest skin? palms, fingertips, soles of feet Average person sheds 50,000 dead cells every minute and 40lbs of them during a lifetime LO 5.1  Thick skin vs thin skin Thin Skin versus Thick Skin These slides show cross-sections of the epidermis and dermis of (a) thin and (b) thick skin. Note the significant difference in the thickness of the epithelial layer of the thick skin. From top, LM × 40, LM × 40. (Micrographs provided by the Regents of University of Michigan Medical School © 2012) LO 5.3  Layers of the epidermis Stratum corneum Most superficial layer 20-30 layers dead flattened cells filled with keratin Glycolipids in extracellular space Stratum granulosum 5 layers of flattened cells Deteriorating organelles Cytoplasm full of granules Stratum spinosum Several layers of keratinocytes Cells contain pre-keratin molecules Stratum basale Most deep layer One layer of mitotically active stem cells Some melanocytes and dendritic cells LO 5.1 Remembering these strange and new words! Create a mnemonic! LO 5.1 Skin structure & function LO 5.1  Papillary layer Dermis Reticular layer Dermis - Flexible connective tissue - Vascular tissue & nervous tissue - Hair follicles & glands - surrounded by epidermal tissue, but reside in the dermis LO 5.1  Dermis Papillary layer – areolar connective tissue (connective tissue – proper loose) – ↑ surface area provides a better bond, and more resistance to scraping and peeling forces keeps the overlying epidermis attached Reticular layer – dense, irregular connective tissue – 80% of the thickness of the dermis – provides support for skin appendages LO 5.1  Dermal circulation Where would you expect to find blood vessels? No blood vessels in epidermis Many blood vessels: Papillary dermis Deep reticular dermis Around sweat glands and hair follicles LO 5.1  Deep thoughts about the skin… Where does the ink go and how does it get there? – In the dermis! LO 5.1  Skin Color Where does skin color come from? Epidermal pigmentation Melanin Carotene Dermal circulation Hemoglobin LO 5.4  Pigments: Melanin Where does it come from? Produced in melanocytes 🡪transferred to keratinocytes Why de we have it? Protects epidermis and dermis from UV radiation prolonged sun exposure will stimulate melanocytes What causes differences in skin color? different levels of melanin production and retention not number of melanocytes LO 5.4 Pigments: Melanin LO 5.4  Pigments: Carotene Where does it come from? Obtained from food – found in orange vegetables – accumulates in stratum corneum & fatty tissues in hypodermis – converted to vitamin A 🡪 essential for vision and epidermal health LO 5.4  Dermal circulation & skin color How does dermal circulation contribute to skin color? RBCs carry hemoglobin to transport oxygen hemoglobin bright red when bound to oxygen What inflammation look like? Reddish skin 🡪 vessels dilate, red tones more pronounced What does cyanosis look like? bluish color to skin 🡪 compromised circulatory system LO 5.4  Blood vessels in thermoregulation During strenuous physical activities, such as skiing (a) or running (c), the dermal blood vessels dilate and sweat secretion increases (b). These mechanisms prevent the body from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to low temperatures (b). LO 5.5 COMPLETE CHECK-IN 5.1  What is found in the dermis? Blood vessels Nervous tissue Appendages and accessory structures: – Hair and hair follicles – Nails – Glands Sweat (sudoriferous) Sebaceous (oil) LO 5.6 – 5.8 Hair and hair follicles Why do we have hair? – Regions of hair Bulb, root, shaft What is it made of? – Primarily hard keratin Tougher Individual cells do not flake off Interesting features: – Associated with Arrector pili What is the function of these? – Derived from epithelial cells – Hair color changes with age LO 5.6, 5.7 Hair and hair follicles Note the patterns of the epidermis – Completely surrounded by epithelial tissue of the epidermis – Bulb sits within the dermis LO 5.6  Nails Nail is an extension of the epidermis Contain hard keratin Growth occurs in nail matrix Pink color due to vascularized tissue below the nail bed LO 5.6 Sweat and sebaceous glands LO 5.8  Sweat (Sudoriferous) glands Eccrine (merocrine) sweat glands – most numerous sweat glands in the body – abundant in palms, soles of feet & forehead – sweat is 99% water + other components Apocrine sweat glands – abundant in axillary and anogenital area – secretions similar to above but directly into hair follicles – same components as above + fatty substance & protein – contributes to body odor LO 5.8  Sebaceous glands Also known as oil glands Associated with hair follicles Small on the body trunk and limbs Large on face, neck, and upper chest Secrete sebum – Softens and lubricates skin and hair – Prevents hair from becoming brittle – Slows water loss from the skin – Possible bactericidal action LO 5.8  Glands Summary LO 5.8  What is acne? Acne is a result of over-productive sebaceous glands, which leads to formation of blackheads and inflammation of the skin. Content Support  What is a gland? A gland is a tissue that secretes a substance. Endocrine glands release substances into the bloodstream Exocrine glands release them into body cavities, the digestive tract, or the surface of the body (anywhere but bloodstream) Marieb and Hoehn 2019 LO 5.8  Where do we find Exocrine Glands? All glands associated with membranes – Integumentary (skin) glands Sweat, sebaceous, mammary (milk) – Glands of mucosal membranes Digestive tract Reproductive tract Basic structure of a gland Respiratory tract Glands of the eye Secretion is produced by glandular epithelium tissue Most exocrine glands have a duct that regulates release of the secretion LO 5.8  Types of exocrine glands Classified by – Shape of glandular portion Tubular, Alveolar (round/spherical), Tuboalveolar (somewhere in between tubular and round) – Arrangement and shape of ducts Simple Coiled Branched Compound branched Content Support Flexure lines form where the dermis is Friction ridges Sweat duct openings closely attached to the consist of epidermal along the crests of underlying structures. ridges that lie on top friction ridges help of dermal ridges. make fingerprints. Features on your skin Content Support Homeostatic imbalances A callous is an area of thickened skin A corn is a large, cone shaped callous Friction increases the rate of epidermal cell division A blister is fluid between the dermis and epidermis Warts are abormal growth of keratin in epidermis Stretch marks (striae) are caused by tearing of the dermal layer of the skin. Content Support  Cancers of the skin One in five Americans develop skin cancer Where would you expect to find them? What type of cells do they occur in? – Basal cell carcinoma 80% of cases, least malignant, excision = 99% cases cured – Squamous cell carcinoma second most common if caught early, prognosis is good – Melanoma cancer of melanocytes survival is low if lesion is 4mm thick 5.13  Cancers of the skin Basal cell carcinoma Squamous cell Melanoma carcinoma Please get them checked out!! – ABCD – recognizing melanoma Asymmetry – not symmetrical (circular) Border irregularity – lesion has indentations Color – pigmented Diameter – larger than 6mm in diameter (size of pencil eraser) 5.13  5.12 Evaluating burns Burn = tissue damage from heat, electricity, radiation, or chemicals Causes cell death, denatures protein, and severe fluid loss Rule of 9s: Estimates fluid loss and percent body burned Burns are generally sterile for 24hrs, after that are extremely susceptible to pathogen infection (nutrient rich environment)  5.12 Burns and Frostbite ⚫ 1st degree: epidermis is damaged ⚫ Heal in a few days ⚫ Example: sunburn ⚫ 2nd degree: epidermis and upper dermis ⚫ Similar to 1st degree + blisters ⚫ Heal in a month ⚫ 3rd degree burns: entire thickness of skin ⚫ Usually not painful, why? ⚫ Debride and graft COMPLETE CHECK-IN 5.2  Powerpoints originally created by K. Bonner and edited by Z. Murphy Images here are swapped – Removal of Pearson – Addition of OpenStax A&P 2nd edition – Some images are created using Biorender and are marked as such