3 Chapter 5: The Integumentary System The skin is notable in several ways:It is uniquely exposed to the environmentDamage or disease in the skin can be easily observedPowers a huge multibillion dollar industrySKIN and HAIR CARE PRODUCTSCOSMETICSELECTIVE PROCEDURES and SURGERYCopyright 2010, John Wiley & Sons, Inc.
4 BOTOX TreatmentTemporary minimizes the appearance of wrinkles and aging lines in the skin.What is the treatment consist of?
5 BOTOX TreatmentBotulinum toxin is produced by the bacteria Clostridium botulinumOne of the most powerful toxinsBTX is a neurotoxic proteinLethal in humans in the microgram to nanogram range based upon intrusion method (injected vs. inhaled)How does it affect the human body?Acts as a neuroblockerInhibits the neurotransmitter AcetylcholineFunctions at neuromuscular junctions to activate muscles
6 Characteristics of Skin Is skin an organ? WHY?Skin is classified as an organ.Composed of many specialized cells and tissuesHow large of an area is covered by skin on an average sized person?22 square feetHow much does skin weigh?10-11 lbsWhat is the study of the skin?DermatologyWhat are the two main layers of skin?Thinner epidermis and thicker dermis
7 Functions of the Skin Work with a partner at your table. What are the functions of the skin?List as many as you can.Provide examples for each function.
8 Functions of skin 1. Temperature regulation: -sweat evaporates when hot.-vascular constriction when cold.2. Protection:-from abrasion and dehydration-from bacterial invasion cannot penetrate normalhealthy skin- acidic pH inhibits growth of some bacteria-from uv light due to melanin-
9 Functions of skin 3. Cutaneous sensations: -temp, touch, pressure, vibration, pain4. Excretion and absorption-small amounts of salts and organic compoundsare removed in perspiration- absorption of drugs or toxic materials5. Synthesis of Vitamin DDegradation of cholesterolRequires exposure to UV radiation in an optimum range of 290 to 300 nmOccurs in the epidermis
10 Vitamin D ExtensionWhat are the guidelines set by WHO for the average amount of sun exposure for Vitamin D synthesis?Is it possible for the body to produce too much Vitamin D? Why?What are some conditions caused by a lack of Vitamin D?
11 Vitamin D ExtensionThe World Health Organization has not released a set sun exposure time due to the risk of skin cancer.No, it is controlled by a negative feedback loop. Excess Vitamin D is quickly broken down to maintain proper levels.Rickets, SAD (Seasonal Affective Disorder), Heart Disease
12 The Structure of Skin: Epidermis, Dermis, and Hypodermis Epidermis - the thin epithelial layer of skinDermis - the thickest, toughest part of skinHypodermis - literally “below the skin”, this subcutaneous layer of connective tissues anchors the skin to deeper tissuesCopyright 2010, John Wiley & Sons, Inc.
13 Specialized Structures and Regions of the Skin The skin includes many specialized secretory and sensory structuresThin skin covers most of the bodyThick skin is found only on the bottom of the feet, and on the palmer surfaces of the hands and fingersCopyright 2010, John Wiley & Sons, Inc.
14 Epidermis Composed of keratinized stratified squamous epithelium Contains 4 types of cellsKeratinocytes=most numerous. Produce keratin which makes cells waterproof.Melanocytes= produce melanin( brown –black pigment)that contributes to skin color. Protect nucleus from UV light. Susceptible to UV lightLangerhans= immune response.Merkel= function in sensation of touch
15 CONCEPT CHECK You know what to do… 1. How does our skin protect us from environmental factors?Provide 4 examples.2. List the four additional functions of the skin.
16 CONCEPT CHECK1. The skin serves as the body’s first line of defense. It provides a waterproof barrier, an acidic surface environment, and its unique structure of keratinized cells makes it resistant to… PointsHeat and ColdAbrasion and DehydrationChemicals Points eachPathogensUV and other forms of Radiation2. Temperature Regulation, Synthesis of Vitamin D, Cutaneous Sensations, Excretion and Absorption3 Points each
17 Layers of the Epidermis Stratum basale=deepest layer.Continually dividing to produce keratinocytes. Melanocytes and merkel cells in this layerStratum spinosum= 8-10 layers langerhans and melanocytes in this layerStratum granulosum= 3-5 layers of flattened keratinocytes nuclei break down and cells die.
18 Layers of the Epidermis Stratum lucidum= only present in palms and soles of feet.3-5 rows of clear dead cellsStratum corneum= rows flat dead cells completely filled with keratin.Continually shed and replaced
19 Structure of the Epidermis Copyright 2010, John Wiley & Sons, Inc.
20 Copyright 2010, John Wiley & Sons, Inc. Thin Verus Thick SkinCopyright 2010, John Wiley & Sons, Inc.
21 Concept CheckYou will need your cell phone to complete the Concept Check.
22 Dermis CT containing collagen and elastic fiber Blood vessels, nerves, glands, hair folliclesPapillary regionunder the epidermisfine elastic fibersDermal papillae(fingerprints)meissner’s corpuscles (nerve endings for touch)temperature, pain
23 Dermis Reticular region dense irregular CT bundles of collagen contains adipose cellshair folliclesnervesoil and sweat glands
24 Skin Color Determined by three pigments Melanin= Amount and type of melanin expressed determines skin color.- freckles - patches- liver(age) spots – clusters of melanocytes damaged by UV light- albinism – inability to produce melaninwhite hair, skin, pink eyes-vitiligo= loss of melanocytes in patches of skin, autoimmune
25 Skin Color2. Hemoglobin= pinkish pigment in skin from dermal capillaries . Transports O2 in blood 3. Carotene= yellow orange pigment found in plants. When eaten deposited in stratum corneum Converted into Vitamin A – Immunity, Vision, General Health Powerful Antioxidant – protection from free radicals May turn skin yellow or orange – Harmless
27 Epidermis ReviewFour Cell types of EpidermisName and function
28 Epidermis Keratinocytes provide waterproof barriers. Melanocytes provide UV absorption/protection.MelaninLangerhans cells initiate immune responses.Identify and mark antigensMerkel cells are receptor cells which assist in spatial sensory touch sensations.Transmit nerve impulses
30 HairPresent on most skin surfaces except palms, palmer surfaces of fingers, soles, toesProtects scalp from UV raysDecreases heat loss from scalpBrows and lashes protect eyes from debrisHair in nostrils and ears protect from debrisTouch perception
31 Review from Yesterday’s Class Why do humans grow hair?Where can hair physiologically grow on the human body?
32 Review Protection Prevention of heat loss Touch perception Nearly any skin surface on the body except for palms of hands and soles of feet.
33 Anatomy of Hair Shaft projects above skin. Straight hair has round transverse sectionWavy hair is ovalCurly hair is kidney shapedRoot=portion below skin
34 Anatomy of Hair 3 concentric regions of hair Medulla=innermost contains pigment and air spacesCortex= contains pigments in dark hair but air in gray or white hairCuticle= single layer of thin flat keratinized cells
35 Hair follicle= surrounds the root Bulb= base of rootMatrix= region of bulb where new hair is producedPapilla= indented area of the bulb where blood vessels enter the hair follicle to nourish the hair cells
36 Hair root plexus= sensory nerve endings wrapped around the bulb of follicle Arrector pilli= smooth muscle attached to each hairContraction causes hair to stand on endgoose bumpsResponse to cold or fear
37 Classification of Hair Lanugo hairs= long and fine, formed in fetus at 20 weeks. Shed before birth, but remain on premiesVellus hair= cover most of the surface area of our bodies colorfulTerminal hairs= long, dark, thick. Eyebrows, eyelashes, scalp, pubic regionVibrisse= nostrils, ear canalHirsutism= excessive and undesireable hair growth in areas not usually covered by hair in women and children (back,face)
38 Hair Color Due to pigment melanin Eumelanin brown to black Pheomelanin yellow/blonde/redWhite or Graying of hair = loss or decrease in pigment
39 DiagramDraw a diagram to represent all of the structures associated with hair structure and function.Color code your diagram.
40 Summary of Dermal Regions Copyright 2010, John Wiley & Sons, Inc.
41 Copyright 2010, John Wiley & Sons, Inc. HairCopyright 2010, John Wiley & Sons, Inc.
42 DO NOW 1. What type of tissue is the dermis composed of? 2. Name two structures found in the papillary region.What is the significance of each structure ?3. What type of tissue is the reticular region composed of?4. What is the name of the pigment responsible for skin colorvariation?5. What effect is expressed in an individual that does notproduce this pigment?
43 DO NOW ANSWERS1. Connective tissue containing collagen and elastic fibers.2. Meissner’s corpuscles – nerve endingsDermal papillae – ridges that produce fingerprints3. Dense irregular CT – tightly woven fibers running in randomdirections4. Melanin5. Albinism – white hair, pinkish white skin, and red eye color.
44 CONCEPT CHECK MAY 2 1. What are the three regions of hair? Spatially represent these regions.2. Which of these regions contain pigment?3. What is the concentration of pigments expressed in an individual having dark brown hair?4. Why is the papilla a vital component for hair growth?
45 Specialized Structures and Regions of the Skin Copyright 2010, John Wiley & Sons, Inc.
51 Concepts Review - Extension 1. How does the skin assist in maintaining homeostasis?2. What is the name given to a type of gland that secretes substances onto an epithelial surface outside of the body?3. What type of feedback loop controls body temperatureWHY?4. What are three components of a feedback loop?
52 Concepts Review - Answers How does the skin assist in maintaining homeostasis?Regulates internal body temperature through sweat glands and pores.What is the name given to a type of gland that secretes substances onto an epithelial surface outside of the body?Exocrine GlandWhat type of feedback loop controls body temperature? WHY?NegativeThe response is opposite of the original stimulusWhat are three components of a feedback loop?Receptor, Control Center, Effector
53 Skin Cancer What is cancer? 1.Basal cell carcinoma most common 70% of skin cancersLeast viciousCured via surgical removalUncontrolled growth of stratum basaloccurs on sun exposed areas of face and neck2. Squamous cell carcinomaKeratinocytes25% of all casesGood prognosis if detected earlySurgical excision or radiationMetastasis through Lymph Nodes
54 3.Malignant melanomaleast common and most dangerousMelanocytesArises from a pre-existing moleFollow A B C D rule for early detectionA=asymmetry 2 sides do not matchB= boarder irregularityC= color multipleD= diameter >6mm
55 Deep Wound Healing (For Wounds Extending into the Dermis) Inflammatory phaseBlood clotting, inflammation, scab formationMigratory phaseEpithelial cells migrate into wound beneath scabProliferative phaseGrowth of cells beneath scabMaturation phaseScab sloughs off, scars may formCopyright 2010, John Wiley & Sons, Inc.
56 Nonspecific Disease Resistance Interactions Animation You must be connected to the internet to run this animation.Copyright 2010, John Wiley & Sons, Inc.
57 Nails Plates of tightly packed keratinized epidermal cells Form clear solid covering over distal portions of fingers and toesHelp grasp and manipulate small objectsProvide protection to fingertips
58 Structure of NailsNail body(plate)= portion that is visible and lies over nail bedFree edge= extends past the finger or toeNail root= portion that is not visibleLunula= whitish semilunar area near rootCuticle= between lunula and nail rootNails are pink because of underlying blood capillaries
59 Copyright 2010, John Wiley & Sons, Inc. NailsCopyright 2010, John Wiley & Sons, Inc.
60 Epidermal Wound Healing This occurs for surface wounds restricted to the epidermis:cells of the stratum basal multiply and migrate to fill the woundthe migrating cells stop migrating when they contact each otheradditional cell divisions repopulate all of the epidermal layersCopyright 2010, John Wiley & Sons, Inc.
61 Epidermal Wound Healing Copyright 2010, John Wiley & Sons, Inc.
62 Deep Wound Healing (For Wounds Extending into the Dermis) Copyright 2010, John Wiley & Sons, Inc.
63 Functions of the Skin (Interaction with Many Other Organ Systems) Regulation of body temperatureInvolves eccrine sweat glands and regulation of blood flow to the skinProtectionPhysical and chemical protection from external threatsCutaneous sensationsTemperature, pain, and several types of pressure are detectedExcretion and absorptionLoss of water and small amounts of other chemicals, non-polar chemicals can be absorbedSynthesis of Vitamin DSunlight on the skin activates the final form of Vitamin DCopyright 2010, John Wiley & Sons, Inc.