Anatomy and Physiology Integumentary System PDF

PowerPoint® Lecture Slides prepared by Meg Flemming Austin Community College CHAPTER 5 The Integumentary System © 2013 Pearson Education, Inc.  Integumentary System Consists of skin, hair, nails and various glands Two major components:...

PowerPoint® Lecture Slides prepared by Meg Flemming Austin Community College CHAPTER 5 The Integumentary System © 2013 Pearson Education, Inc.  Integumentary System Consists of skin, hair, nails and various glands Two major components: Cutaneous membrane (skin) Epidermis - superficial Dermis – underlying connective tissue Accessory structures Hair, nails, exocrine glands Hypodermis (subcutaneous layer) – loose connective tissue under the dermis Separates the integument from deeper tissues and organs Often not considered part of the integumentary system © 2013 Pearson Education, Inc.  Figure 5-1 The General Structure of the Integumentary System. Accessory Structures Cutaneous Membrane Hair Epidermi shaftof s Pore sweat Papillary gland duct Dermis layer Touch receptor Reticular layer Sebaceous gland Arrector pili muscle Sweat gland duct Hypodermi Loading… Hair follicle Pressure receptor s Nerve fibers Sweat gland Arter Cutaneous y Vein plexus Fat © 2013 Pearson Education, Inc.  Five General Functions of the Integument 1. Protection Skin covers underlying tissues and prevents fluid loss 2. Temperature maintenance Skin regulates heat exchange with the environment 3. Synthesis and storage of nutrients Epidermis synthesizes vitamin D3 Dermis stores lipids in adipose tissue © 2013 Pearson Education, Inc.  Five General Functions of the Integument (Introduction) 1. Sensory reception Receptors for pain, pressure, touch, and temperature detect stimuli and send information to nervous system 2. Excretion and secretion Loading… Glands excrete salts, water, and organic wastes Specialized mammary glands secrete milk © 2013 Pearson Education, Inc.  The Epidermis (5-1) Is stratified squamous epithelium Thick skin has five layers (palms, soles) Thin skin has four layers (rest of body) Layers are called strata, from deep to superficial Stratum basale Three intermediate layers Stratum spinosum, stratum granulosum, and stratum lucidum Stratum corneum © 2013 Pearson Education, Inc.  Figure 5-2 The Structure of the Epidermis. Surface Stratum corneum Stratum lucidu m Stratum granulosum Stratum spinosum Stratum basale Basement membrane Dermi s Thick LM x 210 skin © 2013 Pearson Education, Inc.  Stratum Basale (5-1) Also called stratum germinativum Attached to basement membrane by hemidesmosomes Forms epidermal ridges down into dermis Dermis has dermal papillae up into epidermis Epidermis is avascular Ridges and papillae increase surface area for diffusion between dermis and epidermis Contains basal or germinative cells © 2013 Pearson Education, Inc.  Stratum Basale Contours of skin follow ridge patterns Ridge contours are genetically determined => unique to each person and don’t change Fingerprints – ridge patterns of the fingers www.crime- scene- © 2013 Pearson Education, Inc. investigator.net  Intermediate Strata (5-1) Stratum spinosum is the result of stem cell division Stratum granulosum cells make a lot of keratin A protein that provides water resistance and the foundation for hair and nails In others, horns, hooves, feathers, baleen Stratum lucidum cells are densely packed into a highly keratinized layer – only thick skin © 2013 Pearson Education, Inc.  Stratum Corneum (5-1) At exposed surface of the skin Contains 15–30 layers of keratinized or cornified dead cells Cells are connected via desmosomes and are therefore shed in large groups (sheets rather than individuals) Loading… Takes 7-10 days to move from stratum basale to stratum corneum After two weeks in stratum corneum, shed or washed away © 2013 Pearson Education, Inc.  Layers of epidermis http://thealabublog.com/wp-content/uploads/2013/11/Epidermis-Large.jpg  Skin Color (5-2) Role of pigmentation Carotene is orange-yellow, accumulates in epidermis, and comes from orange-colored foods Can be converted to vitamin A required for normal maintenance of epithelial tissues Synthesis of photoreceptors in the eye © 2013 Pearson Education, Inc.  Skin Color (5-2) Role of pigmentation Melanin is brown, yellow-brown, or black, produced by melanocytes near stratum basale cells, absorbs ultraviolet (UV) radiation protecting deeper layers Freckles are areas of greater melanin production Small amount of UV – good for stimulating vitamin D Larger amounts cause burns Variations in skin color are due to differences in melanin production not number of cells © 2013 Pearson Education, Inc.  Figure 5-3 Melanocytes. Melanocyte s in stratum basale Melanin pigment Basement membrane Melanocyte LM x 600 s Melanosome Melanin pigment Melanocyte Basement membrane © 2013 Pearson Education, Inc.  Melanin and sunburn © 2013 Pearson Education, Inc. thebestskinofyourlife.com  Melanin © 2013 Pearson Education, Inc.  Skin Color http://anthro.palomar.edu/adapt/images/ma © 2013 Pearson Education, Inc. p_of_skin_color_distribution.gif  Albinism Light colored skin or hair Melanin is not produced in melanocytes even though of normal abundance http://grandpacliff.com/Animals/Img- Animals/Img-Albinos/albino-tigers-b.jpg albinoafrican.wordpress.com © 2013 Pearson Education, Inc.  Skin Color (5-2) Role of dermal circulation Oxygenated blood is bright red resulting in a flushed, red skin color when dermal blood vessels dilate Short-term paling of the skin occurs with vasoconstriction Cyanosis, a bluish coloration, occurs when blood oxygen supplies are diminished © 2013 Pearson Education, Inc "Cyanosis-adult fingertips" by 7mike5000 derivative of http://commons.wikimedia.org/wiki/File:Raynaud%27s_Syndrome.jpg - Own work. Licensed under CC BY- SA 3.0 via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Cyanosis- adult_fingertips.PNG#/media/File:Cyanosis-adult_fingertips.PNG Beneficial Effects of Sunlight on Skin (5-3) Vitamin D3 is derived from: A cholesterol-related steroid in the epidermis when exposed to sunlight Vitamin D3 is modified by: The liver and the kidneys into calcitriol, essential for calcium and phosphorus absorption in the small intestine Lack of vitamin can lead to weak and flexible bones © 2013 Pearson Education, Inc.  Detrimental Effects of Sunlight on Skin (5-3) Skin cancers Basal cell carcinoma is most common Originating in stratum basale Squamous cell carcinoma found in more superficial layers Both of these are treatable in most cases Surgical removal of tumor is most common treatment © 2013 Pearson Education, Inc.  Detrimental Effects of Sunlight on Skin (5-3) Skin cancers Malignant melanoma is most dangerous Usually begins from a mole, and can metastasize through the lymphatic system Survival depends on when detected and when treatment begins. Avoiding UV radiation by using sunblock can help prevent all three types © 2013 Pearson Education, Inc.  Figure 5-4 Skin Cancers. Basal cell carcinoma Melanoma © 2013 Pearson Education, Inc.  Skin Cancer http://cliniceleven.com/wp-content/uploads/2012/11/Clinic-Eleven-Appearance-Skin-Cancer-Medicine- Paraparaumu-Examples-of-Melanoma.jpg.  The Dermal Papillary Layer (5-4) Named for the dermal papillae Just deep to, and projects up into, the epidermis Contains capillaries and nerves supplying the epidermis © 2013 Pearson Education, Inc.  The Dermal Reticular Layer (5-4) Interwoven meshwork of dense, irregular connective tissue As well as mixed in cells of connective tissue proper Elastic and collagen fibers are present Combine to establish the right balance of flexibility and stability Collagen fibers extend from up into the dermal papillae Down into the hypodermis © 2013 Pearson Education, Inc.  The Dermal Reticular Layer (5-4) Hair follicles and sweat glands derived from epidermis Extend down into the dermis Cutaneous plexus—blood vessels from the hypodermis—extends up into the reticular layer Provides oxygen/nutrients and removes carbon dioxide/waste Blood vessels, lymphatics, and nerves Supply nutrients, eliminate wastes, control secretions, and respond to stimuli © 2013 Pearson Education, Inc.  Figure 5-1 The General Structure of the Integumentary System. Accessory Structures Cutaneous Membrane Hair Epidermi shaftof s Pore sweat Papillary gland duct Dermis layer Touch receptor Reticular layer Sebaceous gland Arrector pili muscle Sweat gland duct Hypodermi Loading… Hair follicle Pressure receptor s Nerve fibers Sweat gland Arter Cutaneous y Vein plexus Fat © 2013 Pearson Education, Inc.  The Hypodermis (5-5) Also called the subcutaneous layer Deep to the dermis without a clear line separating them Not actually part of the integument But stabilizes the skin to underlying tissues Made of areolar tissue with many adipose cells Baby fat – cushions and reduces heat loss © 2013 Pearson Education, Inc.  The Hypodermis (5-5) Fat layers changes as we age Men – neck, upper arms, lower back Women – buttocks, breasts, hips, thighs Both - abdomen No vital organs in area make it an ideal site for subcutaneous injections © 2013 Pearson Education, Inc. wikipedia  Hair and Hair Follicles (5-6) Are accessory organs of the integumentary system Hairs are nonliving structures produced in hair follicles Project above the skin surface everywhere except: The soles of the feet, palms of the hands, sides of the fingers and toes, the lips, and portions of the external genitalia © 2013 Pearson Education, Inc.  Hair and Hair Follicles (5-6) Epidermal layers invaginate into the dermis to form hair follicles Epithelium at the base of follicle caps over the hair papilla Connective tissue that contains capillaries and nerves Epithelial stem cells divide to form hair matrix surrounding the papilla © 2013 Pearson Education, Inc.  Hair and Hair Follicles (5-6) Hair matrix grows, making hair longer, and cells become keratinized and die Halfway to skin surface, it becomes the hair root Above the surface it is called the hair shaft Shaft has three layers of dead cells From outer to inner: cuticle, cortex, and medulla © 2013 Pearson Education, Inc.  Hair and Hair Follicles (5-6) Hair grows according to a hair growth cycle Will grow for 2-5 years Follicle may become inactive for another 2-5 years When another cycle begins, the follicle starts producing and new hair and the old hair is shed Variations in length come from this Size of follicles and shape of hair determine straight (round c.s.) and curly (flattened c.s.) © 2013 Pearson Education, Inc.  Figure 5-5a Hair Follicles and Hairs. Sebaceous gland Hair shaft Hai r Hypodermis Connective tissue sheath of hair Corte x Medull a Hair matrix Hair papilla In this section of skin of the scalp, notice that the two hair follicles extend into the hypo- dermis. © 2013 Pearson Education, Inc.  Figure 5-5b Hair Follicles and Hairs. Hair shaft Sebaceous Boundar gland y Arrector between pili hair shaft muscle and hair root Hair root Connective tissue sheath Hair matrix Hair papilla This drawing shows a longitudinal section of a single hair follicle and hair. © 2013 Pearson Education, Inc.  Figure 5-5c Hair Follicles and Hairs. Connective tissue sheath Wall of hair follicle Cuticle of hair Cortex of hair Medulla of hair This cross section through a hair follicle was taken at the boundary between the hair I shaft and hair root. © 2013 Pearson Education, Inc.  Functions of Hair (5-6) Protects the scalp – uv light, help cushion from light blow, insulates Prevents entry of foreign particles into nose, eyes, and ears Prevents injury via sensory perception – ie swat mosquito Expresses emotional state by hair standing up, due to contraction of arrector pili muscle © 2013 Pearson Education, Inc. https://andreacollo.files.wordpress.com/2014/02/arrector-pili-muscles.jpg.  Hair Color (5-6) Differences due to type and amount of melanin from melanocytes Genetically determined Aging results in less pigment production Causing gray or white hair Due to lack of pigment and bubbles in air shaft © 2013 Pearson Education, Inc.  Sebaceous Glands of the Skin (5-7) Secrete oily sebum into the hair follicle secreted when arrector pili muscles contract – squeezes sebaceous glands and forces secretions into hair follicule Lubricates and inhibits growth of bacteria Sebaceous follicles secrete sebum directly onto: Skin of face, back, chest, nipples, and external genitalia © 2013 Pearson Education, Inc.  Sebaceous Glands of the Skin (5-7) Sebaceous glands are sensitive to hormonal changes – accelerate at puberty Inflamed glands can result in acne © 2013 Pearson Education, Inc.  Figure 5-6 Sebaceous Glands and Their Relationship to Hair Follicles. Hair removed Sebaceous Sebaceous follicle gland Wall of hair follicle Basement membrane Epidermi s Discharge of sebum Dermis Breakdown of cell membranes Mitosis and growth Hypodermis Basal cells Sebaceous LM x gland 150 © 2013 Pearson Education, Inc.  Sweat Glands (5-7) Also called sudoriferous glands Include two types 1. Apocrine sweat glands 2. Merocrine sweat glands © 2013 Pearson Education, Inc.  Apocrine Sweat Glands (5-7) Become active at puberty Secrete sticky, cloudy sweat into hair follicles in armpits, around nipples, and in the pubic region Sweat is food source for bacteria on skin, increasing odor © 2013 Pearson Education, Inc.  Merocrine Sweat Glands (5-7) Also called eccrine sweat glands Very numerous with high numbers on soles and palms Coiled tubular structure secretes watery perspiration directly onto surface of skin Sweat also contains electrolytes, urea, and organic nutrients Sodium chloride gives it the salty taste Function is to cool body through evaporation also provides protection from hazards Dilutes harmful chemicals Contains dermicidin – antibiotic properties © 2013 Pearson Education, Inc.  Figure 5-7 Sweat Glands Merocrine Sweat duct pore Hair shaft Arrector pili muscle Apocrine duct Epidermis Dermis Hypodermis Arter Vein y Merocrine Apocrine sweat Merocrine sweat gland sweat gland gland © 2013 Pearson Education, Inc. (sectioned)  Modified Sweat Glands (5-7) Mammary glands Secrete milk Ceruminous glands Secrete a waxy substance that combines with sebaceous oils to form earwax © 2013 Pearson Education, Inc.  Nails (5-8) Protect tips of fingers and toes Visible nail body Made of dense, keratinized cells recessed under surrounding epithelium Nail bed Deeper level of epithelium covered by nail body © 2013 Pearson Education, Inc.  Nails (5-8) Nail root Where the nail is produced Covered by the cuticle Lunula Pale crescent near root © 2013 Pearson Education, Inc.  Figure 5-8 The Structure of a Nail. Free edge Nail body Nail root Cuticle (site of growth) (eponychium Lunul Nailbed ) a Epidermis Dermis Bone of fingertip © 2013 Pearson Education, Inc.  Repair of the Integument (5-9) Skin regeneration occurs because: Stem cells of epithelium and connective tissue undergo cell division Replacing lost or damaged tissue Time depends on extent of damage Four steps of skin repair 1. Scab formation 2. Tissue granulation 3. Scab removal 4. Scar formation © 2013 Pearson Education, Inc.  Repair of the Integument (5-9) Scab formation A blood clot that forms on the surface Is a temporary "patch" and can help prevent additional microbes from invading the injury Granulation tissue Is formed from the combination of the fibrin blood clot, fibroblasts, and capillaries Macrophages clean up debris © 2013 Pearson Education, Inc.  Repair of the Integument (5-9) Clot removal and a decline of capillaries Scar is formed from remaining meshwork of collagen fibers Degree of scar dependent on severity and location of injury and age of patient Keloid scars are thicker, raised, smooth, and shiny epidermal surface © 2013 Pearson Education, Inc.  Figure 5-9 Events in Skin Repair. Epidermi s Dermis Mast cells Migrating epithelial cells Macrophages and fibroblasts Granulatio n tissue Fibroblasts Scar tissue © 2013 Pearson Education, Inc.  Effects of Burns (5-9) Can be caused by chemicals, heat, radiation, and electrical shock Severity depends on depth into the tissues, and the total area affected © 2013 Pearson Education, Inc.  Table 5-1 A Common Classification of Burns © 2013 Pearson Education, Inc.  Effects of Aging on the Integument (5-10) Skin injuries and infections are more common Likely due to a thinning of the epidermis Sensitivity of immune system is reduced Mainly due to a decrease of macrophages residing in the skin Muscles become weaker and bone strength decreases Due to a decline in vitamin D3 © 2013 Pearson Education, Inc.  Effects of Aging on the Integument (5-10) Sensitivity to sun exposure increases Due to lower amount of melanin production Skin becomes dryer and flakier Due to reduction in glandular secretions Hair thins and loses color Due to low-functioning follicles and decreased melanocyte activity © 2013 Pearson Education, Inc.  Effects of Aging on the Integument (5-10) Sagging and wrinkling of the skin occurs Due to decrease in elastic network, more noticeable when skin has been exposed to a lot of sunlight Ability to lose heat is reduced Due to reduced dermal blood supply and less active sweat glands Skin repairs more slowly Due to slower stem cell division, increasing the threat of infection in cuts © 2013 Pearson Education, Inc.  Figure 5-10 SYSTEM INTEGRATOR Body System Integumentary System Integumentary System Body System The INTEGUMENTARY System The integumentary system S k provides mechanical protection e against environmental hazards. It l e forms the external surface of the t a body and provides protection from l dehydration, environmental M ( p u chemicals, and external forces. a s The integument (skin) is separated g c u e and insulated from the rest of the 1l 8 a body by the hypodermis layer, but 8r it is interconnected with the rest of N () p e the body by an extensive ar circulatory network of blood and g v e o lymphatic vessels. As a result, 2 u 4 s although the protective 1( mechanical functions of the skin Ep) a n can be discussed independently, g d its physiological activities are e o 3 c always closely integrated with 0 ri those of other systems. 2 n e) Car( diop -a vasg cule ar3 (pa7 ge6 467 L) )y m p h a ti c R ( e p s a p g ir e a 5 0t o 0 r) yD (i pg ae gs eti 5v 3e 2U ( ri )p n a g a er 5 y 7( p 2 Rea) pro g due c-6 tiv3 e7 (pa) ge 671 ) © 2013 Pearson Education, Inc.