Get paper in tray Text: P. 171-174 Sponge: Set up Cornell Notes on pg. 29 Topic: 6.1 Layers of the Skin Essential Question: If skin cells are constantly dying and shedding, how come a tattoo does not eventually shed off? 6.1 Layers of the Skin 2.1 Atoms, Ions, and Molecules If skin cells are constantly dying and shedding, how come a tattoo does not eventually shed off? Get paper in tray Text: P. 171-174

Objective Students will understand the structure of the layers of the skin Students will

Chapter 6 Integumentary System---Skin Functions of the Integumentary System Maintains homeostasis Regulates body temperature Protective covering Prevents microorganisms from entering the body Retards water loss Houses sensory receptors Contains immune system cells Synthesizes chemicals Excretes small amounts of waste

Two or more kinds of tissue grouped together and performing specialized functions= organ The skin is the largest organ in the body by weight

Skin cells Skin cells: help produce Vitamin D needed for normal bone and tooth development Some cells (keratinocytes) produce substances that simulate development of some WBCs

Layers of Skin 1. Epidermis 2. Dermis The skin includes 2 distinct tissue layers: 1. Epidermis 2. Dermis -Subcutaneous layer or hypodermis

Layers of skin

Epidermis 1. Epidermis: Made up of stratified squamous epithelium Lacks blood vessels Nourished by dermal blood vessels

Epidermis As new cells grow they push old cells farther from nutrient supply and they die Become keratinized- harden, becomes waterproof Eventually shed

Hypothesize the place(s) on your skin that are the thickest AND why. Thickest on palms and soles of feet Thin everywhere else (0.07-0.12mm thick) Cell division is higher in areas where skin is rubbed or pressed regularly

Make a picture bubble Map The Layers of the Human Skin 3m47s The Human Skin Animation 1m7s Make a picture bubble Map Add information from the video into your pictures of the layers of the skin Layer of dead flat tissue

Layers of the epidermis Stratum corneum- Outermost layer, fully keratinized Stratum lucidum- Thickened skin of palms and soles (only) Stratum granulosum- Layers of granular cells that contain fibers of keratin Stratum spinosum- Thickest layer, Limited mitosis Stratum basale (bă-sail-ē)- Deepest layer, undergoing mitosis, contains melanocytes

Melanocytes- specialized cells that produce the dark pigment melanin Provides skin color Absorbs UV rays Prevents mutations in the DNA or skin cells and other damaging effects Mel-ano-cytes The more melanin produced the darker the skin

2. Dermis: Binds epidermis to underlying tissues Composed of: Dense connective tissue (irregular) Muscle cells Nerve cell endings Specialized sensory receptors Blood vessels Hair follicles Glands (sweat/oil)

Tattoos Ink injected into the dermis Color is permanent Dermis cells are not shed! Tattoo Removal Lasers shatters ink molecules Immune system removes debris Before lasers, tattoos were scraped, frozen, or cut away PAINFUL!!!!!

The Tattoo Removal Process 3m20s

Subcutaneous Layer Subcutaneous Layer: NOT part of the skin Binds the skin to underlying organs Insulates Composed of: Loose connective tissue Adipose tissue Major blood vessels

Layers of skin

Integumentary System Crash Course A+P 8m52s Take 15 bullets on p. 28 https://www.youtube.com/watch?v=Orumw-PyNjw