AGENDA NOV 9 Objective: Identify the different layers of skin and their functions in the human body. 1. Chapter 4 TEST RESULTS 2. Introduce Chapter 5 Integumentary System – Characteristics and Functions 3. Chapter 5 Project and Grading Rubric 4. Homework and Review – CONCEPT CHECK TOMORROW! – Skin Projects

CHAPTER 5: Integumentary System

Copyright 2010, John Wiley & Sons, Inc. Chapter 5: The Integumentary System The Integumentary System consists of skin and accessory structures Skin is the first line of the body’s defense. Also assists the body through other functions.

Copyright 2010, John Wiley & Sons, Inc. 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 – Emotions are expressed through changes in our appearance – Our appearance also reflects our sense of identity, thus substantial effort and money is spent on the skin

Characteristics of Skin Is skin an organ? WHY? Skin is one of the largest organs 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? lbs What is the study of the skin? Dermatology What are the two main layers of skin? Thinner epidermis and thicker dermis

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.

CONCEPT CHECK You know what to do… How does our skin protect us from environmental factors? Provide 3 examples.

CONCEPT CHECK The skin serves as the body’s first line of defense. It provides a waterproof barrier and its unique structure of keratinized cells makes it resistant to… 4 Points – Heat – Cold – Chemicals 2 Points each – Pathogens – UV and other forms of Radiation 10 POINTS TOTAL

AGENDA NOV 10 Objective: Identify the different layers of skin and their functions in the human body. 1. Chapter 4 TEST RESULTS 2. Project Topics 3. Functions of the Integumentary System 4. Homework and Review – Projects – QUIZ on THURSDAY

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 -

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

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?

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

Concept Check You will need your cell phone to complete the Concept Check dc-4ea8-ab de71f8f dc-4ea8-ab de71f8f

AGENDA NOV 11 Objective: Identify the different layers of skin and their functions in the human body. 1. Types and Layers of Skin – Characteristics and Functions – Cell Types 2. Homework and Review – Projects – QUIZ on THURSDAY

Copyright 2010, John Wiley & Sons, Inc. 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. 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

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

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.

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

Copyright 2010, John Wiley & Sons, Inc. Cells of the Epidermis

Copyright 2010, John Wiley & Sons, Inc. Thin Verus Thick Skin

AGENDA NOV 12 Objective: Identify the different layers of skin and their functions in the human body. 1. QUIZ – 10 minutes 2. The Dermis – Regions of the Dermis – Hair and Skin Color 3. Homework and Review – Projects – BE READY TO PRESENT ON MONDAY NOV 16

Epidermis Review Four Cell types of Epidermis – Name and function Five layers of Epidermis – Order them beginning with the surface layer of skin.

Epidermis Keratinocytes provide waterproof barriers. – Keratin 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

Layers of the Epidermis Stratum corneum – Surface layers of skin Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale – deepest layers of skin

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

Dermis Reticular region dense irregular CT bundles of collagen contains adipose cells hair follicles nerves oil and sweat glands