Essentials of Anatomy and Physiology Lecture Outline PDF

Because learning changes everything.® Chapter 5 Lecture Outline Essentials of Anatomy and Physiology Third Edition Kenneth S. Saladin, Robin K. McFarland © 2022 McGraw Hill, LLC. All rights reserved....

Because learning changes everything.® Chapter 5 Lecture Outline Essentials of Anatomy and Physiology Third Edition Kenneth S. Saladin, Robin K. McFarland © 2022 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC.  The Integumentary System Consists of skin, hair, nails, and cutaneous glands Important for individual self-image Significant in physical exam Provides clues to health and to disorders such as liver cancer, anemia, and lung disease © McGraw Hill, LLC 2  The Skin and Subcutaneous Tissue 1 Learning Outcomes: Describe the functions of the skin Name the cell types of the epidermis and identify their functions Name and describe the layers of the epidermis and dermis Explain what accounts for various normal and pathological skin colors Name the various physical markings of the skin © McGraw Hill, LLC 3  The Skin and Subcutaneous Tissue 2 Skin Membrane covering external surface of body Two layers: Superficial epidermis – epithelium Deeper dermis – connective tissue Hypodermis Loose connective tissue between skin and muscles © McGraw Hill, LLC 4  Structure of the Skin and Accessory Organs (Figure 5.1) Access the text alternative for slide images. © McGraw Hill, LLC 5  Functions of the Skin 1 Resistance to trauma and infection Cells packed with tough keratin and linked by strong desmosomes Few organisms are able to penetrate if intact Dryness of skin and protective acid layer helps keep organisms on skin in check Water retention Prevents body from losing or absorbing too much water © McGraw Hill, LLC 6  Functions of the Skin 2 Vitamin D synthesis The first step of vitamin D synthesis is carried out by epidermal cells Needed for bone development, maintenance Sensation Body’s largest sense organ; has nerve endings for temperature, touch, pressure, vibration, and injury © McGraw Hill, LLC 7  Functions of the Skin 3 Thermoregulation Regulates heat exchange with environment Increases or reduces blood flow close to body surface Sweats in response to overheating Nonverbal communication Numerous small facial muscles produce subtle and varied expressions © McGraw Hill, LLC 8  Structure Skin characteristics Body’s largest organ; about 15% of body weight Most of the skin is 1 to 2 mm thick Ranges from 0.5mm to 6 mm mostly due to variations in dermis Lacks a blood supply; depends on the vasculature of the underlying dermis As epidermal cells move up away from this blood supply, they die © McGraw Hill, LLC 9  The Epidermis 1 Cells of the epidermis: Keratinized stratified squamous epithelium (30 to 40 cells thick in some places) Most cells are keratinocytes Packed with keratin Deepest cells are rounded; become squamous as move superficially Dendritic cells Alert immune system to ward off infection © McGraw Hill, LLC 10  The Epidermis 2 Cells of the epidermis, continued Melanocytes Produce the pigment melanin, which protects underlying tissues from ultraviolet rays from the sun In the deepest layer of the epidermis Tactile cells Cells specialized for touch Stem cells Continually divide and replace keratinocytes that die © McGraw Hill, LLC 11  Layers of the Epidermis 1 Layers of the epidermis, from deepest to most superficial: Stratum basale Deepest layer; a single layer of cells Contains stem cells, keratinocytes, melanocytes, and tactile cells Stratum spinosum Many layers of keratinocytes and dendritic cells Cease dividing as pushed upward, and start synthesizing keratin and flattening © McGraw Hill, LLC 12  Layers and Cell Types of the Epidermis (Figure 5.2) Access the text alternative for slide images. © McGraw Hill, LLC 13  Layers of the Epidermis 2 Layers of the epidermis, from deepest to most superficial, continued: Stratum granulosum Three to five layers of flat keratinocytes Keratin filaments in thick bundles produce water barrier Cells die; the water barrier cuts them off from nutrients Stratum lucidum Present only in thick epidermis of palms and soles Clear layer of dead cells © McGraw Hill, LLC 14  Layers of the Epidermis 3 Layers of the epidermis, from deepest to most superficial, continued: Stratum corneum Up to 30 layers of dead keratinocytes that are packed with keratin Gives skin toughness Cells flake off, or exfoliate, as dander Replaced by new cells 30 to 40 days from “birth” to exfoliation © McGraw Hill, LLC 15  Dermis 1 From 0.2 mm to 6 mm thick Consists mainly of collagen but also has elastic and reticular fibers, and the cells of fibrous connective tissue Has many blood vessels, nerve endings, sweat and sebaceous glands Hair and nails are rooted here Where skeletal muscles attach on face © McGraw Hill, LLC 16  Dermis 2 Boundary between epidermis and dermis is made of upward waves called dermal papillae Fingerlike extensions of dermis Interlock with epidermis; help resist slippage of epidermis and give skin more resistance to stress Form fingerprints Blisters form here, between epidermis and dermis Dermal capillaries supply bloodless epidermis © McGraw Hill, LLC 17  Dermis 3 Zones of the dermis Papillary layer Thin zone of areolar tissue in and near dermal papillae Loosely organized; allows leukocytes to move around easily Reticular layer Deeper layer; four-fifths of dermis Has thick bundles of collagen, elastic fibers, fibroblasts, and clusters of adipocytes Embedded in this layer are sweat glands, nail roots, and hair follicles © McGraw Hill, LLC 18  Hypodermis Hypodermis (subcutaneous tissue) Underlies dermis Looser connective tissue and adipose tissue Binds skin to muscles or other tissues Pads body Serves as an energy reservoir; 50% of body fat is found here Provides thermal insulation Differs in thickness, distribution between sexes © McGraw Hill, LLC 19  Skin Color 1 Melanin Most significant factor in skin color Produced by melanocytes, transferred to keratinocytes The number of melanocytes is about the same in people of different skin colors but darker skinned individuals make more melanin © McGraw Hill, LLC 20  Variations in Skin Pigmentation (Figure 5.3) a: (top): ©Tom & Dee Ann McCarthy/Corbis (bottom): Dennis Strete/McGraw-Hill Education b: (top): Creatas/PunchStock ( bottom): Dennis Strete/McGraw-Hill Education Access the text alternative for slide images. © McGraw Hill, LLC 21  Skin Color 2 Melanin, continued Blocks ultraviolet radiation, which can cause DNA damage and skin cancer In response to ultraviolet rays, melanocytes increase their production; leads to tanning effect Tan fades as melanin is degraded in older keratinocytes Freckles and moles are local concentrations of melanin © McGraw Hill, LLC 22  Skin Color 3 Other factors in skin color: Hemoglobin Red pigment of blood; gives reddish hue to skin Carotene Yellow pigment from vegetables Concentrated in stratum corneum and subcutaneous fat © McGraw Hill, LLC 23  Skin Color and Diagnosis 1 Cyanosis Blueness of skin from oxygen deficiency in blood For example, drowning, emphysema, and cold weather Erythema Abnormal redness of the skin For example, sunburn, exercise, and hot weather © McGraw Hill, LLC 24  Skin Color and Diagnosis 2 Hematoma A bruise, which is a mass of clotted blood For example, from trauma, platelet deficiency, and diseases Pallor Temporary pale color from little cutaneous blood flow For example, from stress, circulatory shock, and cold temperatures © McGraw Hill, LLC 25  Skin Color and Diagnosis 3 Albinism Hereditary lack of pigmentation in skin, hair, and eyes Inability to synthesize melanin Jaundice Yellowing of skin and whites of eyes For example, liver diseases and some blood diseases © McGraw Hill, LLC 26  Perspectives on Health: Skin Cancer 1 Caused by UV radiation Three forms, with different origins: basal cell carcinoma, squamous cell carcinoma, and melanoma © McGraw Hill, LLC 27  Perspectives on Health: Skin Cancer 2 Basal cell carcinoma Arises from the stratum basale Most common, least dangerous Squamous cell carcinoma Arises in the stratum spinosum Easily cured, but can be lethal if not caught early © McGraw Hill, LLC 28  Perspectives on Health: Skin Cancer 3 Melanoma Rarest but the most deadly Usually arises from melanocytes of a preexisting mole ABCD rule is used for recognizing melanoma: Asymmetry – mole should be symmetrical Border – border should be defined and regular Color – mole should be one color Diameter – should be smaller than 6mm © McGraw Hill, LLC 29  Skin Cancer (Figure 5.4) a: jax10289/Shutterstock b: DR P. Marazzi/ Science Photo Library/Alamy c: ©National Cancer Institute © McGraw Hill, LLC 30  Perspectives on Health: Burns 1 Burns can be caused by fires, hot water, electricity, chemicals and the sun Three types: first degree, second degree, third degree First degree Involve only the epidermis Redness, swelling, pain For example, most sunburns © McGraw Hill, LLC 31  Perspectives on Health: Burns 2 Second degree Involve the entire epidermis and part of the dermis Like first degree, partial-thickness burn Third degree, or full-thickness burn Destroys the epidermis and all of the dermis Often needs skin grafts Need to worry about fluid loss and infections © McGraw Hill, LLC 32  Before You Go On to Accessory Organs 1 How does the skin protect against infectious organisms? Describe two ways in which the skin helps to regulate body temperature. Name the five kinds of epidermal cells and describe their functions. © McGraw Hill, LLC 33  Before You Go On to Accessory Organs 2 List the five layers of epidermis from deep to superficial. What are the distinctive features of each? What are the two layers of the dermis? What type of tissue composes each layer? Name the pigments responsible for normal skin colors, and explain how certain conditions can produce pathological discoloration of the skin. © McGraw Hill, LLC 34  Accessory Organs 1 Learning Outcomes: Describe the histology of a hair and its follicle Explain how a hair grows Discuss the purposes served by various kinds of hair Describe the structure and function of nails Name two types of sweat glands, and describe the structure and function of each Describe the location, structure, and function of other glands of the skin © McGraw Hill, LLC 35  Accessory Organs 2 Accessory organs (appendages) of skin Hair, nails, and cutaneous glands Originate in epidermis of embryo, but then penetrate deeply into dermis or hypodermis © McGraw Hill, LLC 36  Hair Slender filament of keratinized cells growing from a hair follicle, a tube of epithelium and connective tissue Made of stronger, harder keratin than epidermis Occurs everywhere except lips, nipples, parts of genitals, palms and soles, lateral fingers and toes Density is fairly constant between individuals Differences in hairiness are due to differences in hair texture and pigmentation © McGraw Hill, LLC 37  Structure of the Hair and Follicle 1 Hair structure Shaft Portion of the hair above the skin surface Root Portion of the hair below the skin surface Bulb Swelling at lower end of root © McGraw Hill, LLC 38  Structure of a Hair and its Follicle (Figure 5.5) b: © Ed Reschke/Getty Images Access the text alternative for slide images. © McGraw Hill, LLC 39  Structure of the Hair and Follicle 2 Hair structure, continued Dermal papilla Vascular connective tissue growing into bulb; provides hair with nutrition Hair matrix Just above bulb Site of cellular mitosis and hair growth © McGraw Hill, LLC 40  Structure of the Hair and Follicle 3 Hair structure, continued Cuticle Surface layer of hair Cortex Layer beneath cuticle; makes up most of hair bulk Medulla Central core of hair; found only in thickest hair Root sheath Layer of epithelium and dermis alongside hair © McGraw Hill, LLC 41  More Structure of the Hair and Follicle Hair structure, continued Hair receptors Nerve fibers coiled around follicle Respond to hair movements Piloerector (pilomotor) muscle Smooth muscle associated with each follicle Contracts in response to stimuli; makes hair stand upright For example, cold, fear, and touch © McGraw Hill, LLC 42  Hair Color Due to different types and proportions of melanin Eumelanin Color in black and brown hair Pheomelanin In shades of blond to red Gray and white hair From air in medulla and little pigment © McGraw Hill, LLC 43  Hair Growth Grows by mitosis of cells in hair matrix Hair and follicle cells are pushed toward skin surface; die and become progressively keratinized Grows about 1 mm in 3 days Grows for 6 to 8 years Resting phase, 1 to 3 months Lose 50 to 100 scalp hairs per day © McGraw Hill, LLC 44  Hair Functions 1 Scalp hair Helps retain heat Protects scalp from sunburn and skin cancer Beard, pubic, and axillary hair Begin growing at puberty; advertise sexual maturity Absorb aromatic secretions Hair on trunk and limbs Largely an evolutionary remnant, but plays a sensory role © McGraw Hill, LLC 45  Hair Functions 2 Eyebrows Accentuate facial expressions Keep sweat and debris out of eyes Guard hairs (vibrissae) Block foreign particles from nostrils, auditory canals, and eyes Eyelashes Shield eyes from debris © McGraw Hill, LLC 46  Nails 1 Nail characteristics Derivatives of stratum corneum Composed of thin dead cells filled with hard keratin Can be used as strong tools Fingernails grow at 1 mm/week; toenails grow more slowly © McGraw Hill, LLC 47  Nails 2 Parts of a nail Nail plate Visible portion covering fingertip Nail bed The epidermis underlying most of plate Nail fold Thickening of skin around margins of plate © McGraw Hill, LLC 48  Anatomy of a Fingernail (Figure 5.6) Access the text alternative for slide images. © McGraw Hill, LLC 49  Nails 3 Parts of a nail, continued Free edge Part of plate extending beyond nail bed Nail matrix At proximal edge of nail Growth zone; concealed beneath skin Cells are added by mitosis to plate Nails can be used to diagnose diseases of heart, lungs and liver © McGraw Hill, LLC 50  Cutaneous Glands The skin has five types of glands: eccrine sweat glands, apocrine sweat glands, sebaceous glands, ceruminous glands and mammary glands Sweat glands are also called sudoriferous glands © McGraw Hill, LLC 51  Cutaneous Glands (Figure 5.7) a–c: Dennis Strete/McGraw-Hill Education Access the text alternative for slide images. © McGraw Hill, LLC 52  Sweat Glands 1 Eccrine sweat glands Most sweat glands are of this type; widespread in skin Produce watery perspiration, sweat, that cools the body Ducts empty onto skin surface © McGraw Hill, LLC 53  Sweat Glands 2 Eccrine sweat glands, continued Sweat Begins as filtrate of blood plasma 99% water, also contains salts and wastes Insensible perspiration – 500 mL per day; no noticeable wetness of the skin Diaphoresis – noticeable wetness from sweating Skin also loses water via cutaneous transpiration Water diffuses between keratinocytes and evaporates off skin surface © McGraw Hill, LLC 54  Sweat Glands 3 Apocrine sweat glands In groin, anal region, axilla, areola, and beard Sparse or absent in some people Ducts lead to hair follicles Larger lumen than merocrine glands Sweat has more fatty acids than merocrine sweat © McGraw Hill, LLC 55  More Sweat Glands Apocrine sweat glands, continued Respond to stress and sexual stimulation Do not develop until puberty Produce pheromones Chemicals that influence other members of species Scent is retained by pubic and axillary hair © McGraw Hill, LLC 56  Sebaceous Glands Produce oily secretion, sebum Keeps skin and hair from being dry Flask-shaped with short ducts that open into hair follicle Holocrine glands © McGraw Hill, LLC 57  The Skin and Accessory Organs (Figure 5.1) Access the text alternative for slide images. © McGraw Hill, LLC 58  Ceruminous Glands Found only in auditory canal Secrete cerumen (earwax) Simple, coiled, tubular glands that have ducts leading to skin surface Keeps eardrum pliable, waterproofs auditory canal and has bactericidal effect © McGraw Hill, LLC 59  Aging of the Integumentary System 1 Hair becomes thinner, turns gray Skin and hair become dryer from atrophy of sebaceous glands Loss of collagen and elastin from dermis makes skin thinner, looser Blood vessels become fragile; skin bruises easily Poorer circulation leads to decreased healing © McGraw Hill, LLC 60  Aging of the Integumentary System 2 Fewer dendritic cells so more susceptible to infection Atrophy of blood vessels, sweat glands and subcutaneous fat leads to difficulty in regulating body temperature More vulnerable to hypo- and hyperthermia Photoaging – degenerative changes due to exposure to UV rays Age spots, wrinkles, skin cancer © McGraw Hill, LLC 61  Before You Go On to The Skeletal System 1 Name and define the three regions of a hair from its base to its tip, and the three layers of a thick hair seen in cross section. State the functions of the hair papilla, hair receptors, and piloerector. State a reasonable theory for the functions of hair of the eyebrows, eyelashes, scalp, nostrils, and axilla. © McGraw Hill, LLC 62  Before You Go On to The Skeletal System 2 Define or describe the nail plate, nail fold, and nail matrix. How do eccrine and apocrine sweat glands differ in structure and function? What other type of gland is associated with hair follicles? How does its mode of secretion differ from that of sweat glands? © McGraw Hill, LLC 63 Because learning changes everything. ® www.mheducation.com © 2022 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC.