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CHAPTER 5: Integumentary System

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1 CHAPTER 5: Integumentary System

2 ZIKA Virus Extension

3 Chapter 5: The Integumentary System
The skin is notable in several ways: It is uniquely exposed to the environment Damage or disease in the skin can be easily observed Powers a huge multibillion dollar industry SKIN and HAIR CARE PRODUCTS COSMETICS ELECTIVE PROCEDURES and SURGERY Copyright 2010, John Wiley & Sons, Inc.

4 BOTOX Treatment Temporary minimizes the appearance of wrinkles and aging lines in the skin. What is the treatment consist of?

5 BOTOX Treatment Botulinum toxin is produced by the bacteria Clostridium botulinum One of the most powerful toxins BTX is a neurotoxic protein Lethal 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 neuroblocker Inhibits the neurotransmitter Acetylcholine Functions 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 tissues How large of an area is covered by skin on an average sized person? 22 square feet How much does skin weigh? 10-11 lbs What is the study of the skin? Dermatology What 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 normal healthy 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, pain 4. Excretion and absorption -small amounts of salts and organic compounds are removed in perspiration - absorption of drugs or toxic materials 5. Synthesis of Vitamin D Degradation of cholesterol Requires exposure to UV radiation in an optimum range of 290 to 300 nm Occurs in the epidermis

10 Vitamin D Extension What 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 Extension The 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 skin Dermis - the thickest, toughest part of skin Hypodermis - literally “below the skin”, this subcutaneous layer of connective tissues anchors the skin to deeper tissues Copyright 2010, John Wiley & Sons, Inc.

13 Specialized Structures and Regions of the Skin
The skin includes many specialized secretory and sensory structures Thin skin covers most of the body Thick skin is found only on the bottom of the feet, and on the palmer surfaces of the hands and fingers Copyright 2010, John Wiley & Sons, Inc.

14 Epidermis Composed of keratinized stratified squamous epithelium
Contains 4 types of cells Keratinocytes=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 light Langerhans= 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 CHECK 1. 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… Points Heat and Cold Abrasion and Dehydration Chemicals Points each Pathogens UV and other forms of Radiation 2. Temperature Regulation, Synthesis of Vitamin D, Cutaneous Sensations, Excretion and Absorption 3 Points each

17 Layers of the Epidermis
Stratum basale=deepest layer. Continually dividing to produce keratinocytes. Melanocytes and merkel cells in this layer Stratum spinosum= 8-10 layers langerhans and melanocytes in this layer Stratum 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 cells Stratum 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 Skin Copyright 2010, John Wiley & Sons, Inc.

21 Concept Check You will need your cell phone to complete the Concept Check. de71f8f

22 Dermis CT containing collagen and elastic fiber
Blood vessels, nerves, glands, hair follicles Papillary region under the epidermis fine elastic fibers Dermal papillae(fingerprints) meissner’s corpuscles (nerve endings for touch) temperature, pain

23 Dermis Reticular region dense irregular CT bundles of collagen
contains adipose cells hair follicles nerves oil 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 melanin white hair, skin, pink eyes -vitiligo= loss of melanocytes in patches of skin, autoimmune

25 Skin Color 2. 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 Review Four Cell types of Epidermis Name and function

28 Epidermis Keratinocytes provide waterproof barriers.
Melanocytes provide UV absorption/protection. Melanin Langerhans cells initiate immune responses. Identify and mark antigens Merkel cells are receptor cells which assist in spatial sensory touch sensations. Transmit nerve impulses


30 Hair Present on most skin surfaces except palms, palmer surfaces of fingers, soles, toes Protects scalp from UV rays Decreases heat loss from scalp Brows and lashes protect eyes from debris Hair in nostrils and ears protect from debris Touch 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 section Wavy hair is oval Curly hair is kidney shaped Root=portion below skin

34 Anatomy of Hair 3 concentric regions of hair
Medulla=innermost contains pigment and air spaces Cortex= contains pigments in dark hair but air in gray or white hair Cuticle= single layer of thin flat keratinized cells

35 Hair follicle= surrounds the root
Bulb= base of root Matrix= region of bulb where new hair is produced Papilla= 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 hair Contraction causes hair to stand on end goose bumps Response 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 premies Vellus hair= cover most of the surface area of our bodies colorful Terminal hairs= long, dark, thick. Eyebrows, eyelashes, scalp, pubic region Vibrisse= nostrils, ear canal Hirsutism= 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/red White or Graying of hair = loss or decrease in pigment

39 Diagram Draw 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.
Hair Copyright 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 color variation? 5. What effect is expressed in an individual that does not produce this pigment?

43 DO NOW ANSWERS 1. Connective tissue containing collagen and elastic fibers. 2. Meissner’s corpuscles – nerve endings Dermal papillae – ridges that produce fingerprints 3. Dense irregular CT – tightly woven fibers running in random directions 4. Melanin 5. 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.

46 Odoriferous Emanations

47 Glands Sebaceous(oil)
Found everywhere except for soles and palms of feet Secrete oily substance called sebum Softens and lubricates the skin. Decreases skin permeability to water and is bacteriacidal

48 Sudoriferous (sweat) Found all over body 2-5 million/person Produces sweat which functions as temperature regulation and waste elimination

49 Sudoriferous (sweat) a.Eccrine – on most body surfaces b.Apocrine= found in armpit, groin and facial region in males. Body Odor Activate due to stress or pain

50 Ceruminous (wax) -External ear -Produce waxy secretion cerumen Provide sticky barrier to foreign bodies entering ear canal

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 temperature WHY? 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 Gland What type of feedback loop controls body temperature? WHY? Negative The response is opposite of the original stimulus What 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 cancers Least vicious Cured via surgical removal Uncontrolled growth of stratum basal occurs on sun exposed areas of face and neck 2. Squamous cell carcinoma Keratinocytes 25% of all cases Good prognosis if detected early Surgical excision or radiation Metastasis through Lymph Nodes

54 3.Malignant melanoma least common and most dangerous Melanocytes Arises from a pre-existing mole Follow A B C D rule for early detection A=asymmetry 2 sides do not match B= boarder irregularity C= color multiple D= diameter >6mm

55 Deep Wound Healing (For Wounds Extending into the Dermis)
Inflammatory phase Blood clotting, inflammation, scab formation Migratory phase Epithelial cells migrate into wound beneath scab Proliferative phase Growth of cells beneath scab Maturation phase Scab sloughs off, scars may form Copyright 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 toes Help grasp and manipulate small objects Provide protection to fingertips

58 Structure of Nails Nail body(plate)= portion that is visible and lies over nail bed Free edge= extends past the finger or toe Nail root= portion that is not visible Lunula= whitish semilunar area near root Cuticle= between lunula and nail root Nails are pink because of underlying blood capillaries

59 Copyright 2010, John Wiley & Sons, Inc.
Nails Copyright 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 wound the migrating cells stop migrating when they contact each other additional cell divisions repopulate all of the epidermal layers Copyright 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 temperature Involves eccrine sweat glands and regulation of blood flow to the skin Protection Physical and chemical protection from external threats Cutaneous sensations Temperature, pain, and several types of pressure are detected Excretion and absorption Loss of water and small amounts of other chemicals, non-polar chemicals can be absorbed Synthesis of Vitamin D Sunlight on the skin activates the final form of Vitamin D Copyright 2010, John Wiley & Sons, Inc.

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