Do Now Read the article about cellulite and answer the questions.

Finish Lab Get with your partner from yesterday to finish your lab. You will do the fourth activity of the lab. Follow the directions to experiment with temperature receptors in the skin.

DO NOW Hand in your skin sensitivity lab. What conclusions did you make from this lab?

Objectives To explain the function of the integumentary system. To identify the components of the epidermis. To list the strata of the epidermis.

The Integumentary System: An Overview

Functions: Protective covering Helps regulate body temperature Retards water loss from deeper tissues Houses sensory receptors Synthesizes biochemicals Excretes small quantities of waste

Consists of… Cutaneous membrane Epidermis Dermis Accessory structures- hair, sweat glands, sebaceous glands etc. Subcutaneous layer (hypodermis)

Components Figure 5.1

The Epidermis

Thin Skin and Thick Skin The epidermis is composed of layers of keratinocytes- cells that produce keratin Thin skin = four layers (strata) Thick skin = five layers Figure 5.2

The Epidermis Composed of stratified squamous epithelium Lacks blood vessels Older cells are pushed to the top and harden in a process called keratinization.

Layers of the epidermis: From deep……. Stratum basale/ germinativum Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum …… to superficial

The Structure of the Epidermis Figure 5.4

Epidermis Cell Layers Germinative Spinosum- spiny layer Basal cells (stem) are reproducing Spinosum- spiny layer Granulosum- grainy layer Stops dividing, start producing keratin Lucidum The clear layer found only in thick skin Corneum Exposed to surface and shed every 2 wks.

Skin color depends on… Blood supply Carotene Melanin Interrupted blood supply leads to cyanosis- blue! Carotene Orange-yellow pigment found in orange vegetables Melanin Yellow-brown pigment Protects us from UV radiation Produced by melanocytes

Melanocytes Figure 5.5a, b

Epidermal cells Synthesize vitamin D3 (cholecalciferol) when exposed to UV Aids in absorption of calcium and phosphorus- needed for bone strength Respond to epidermal growth factor Growth Division Repair Secretion

Skin Cancer

Lab Begin working on the “Integumentary System” lab. Do as much as you can in the rest of the period. The slides will be posted on the powerpoint for clarity.

Do Now Read the article “Whats the skinny on tattoos” on my desk and answer the questions.

Objectives The explain the components of the dermis. To understand why tattoos are permanent. To identify accessory organs of the integument and explain their function.

The Dermis

Dermal Organization Located between epidermis and subcutaneous layer Anchors accessory structures- hair follicles, sweat glands, blood vessels etc. Two components: Outer papillary layer Deep reticular layer

Layers of the Dermis Papillary layer Reticular layer Areolar tissue Contains blood vessels, lymphatics, sensory nerves of epidermis Reticular layer Dense irregular connetive tissue Contains network of collagen and elastic fibers to resist tension

Dermal Circulation Figure 5.8

Stretch Marks Caused by excessive stretching of the dermis Patterns of collagen and elastic fibers form lines of cleavage

Lines of Cleavage of the Skin Figure 5.7

Hypodermis Elastic areolar tissue and adipose tissue Stabilizes skins position against underlying organs and tissues Shock absorber and insulator Few capillaries and no vital organs Subcutaneous injection is useful to administer drugs

Hairs Composed of keratinized dead cells that are produced in hair follicles Project deep into the dermis and often into the hypodermis

Structures Hair papilla Root Shaft Connective tissue containing capillaries and nerves Root Anchors hair into skin Shaft Part we see on the surface Consists of three layers Cuticle- overlapping shingle layer Cortex- underlying layer- pigments Medulla- core of hair

Structures Contd. Sebaceous Glands Arrector pili muscle Discharge oily substance into hair follicles Inhibits growth of bacteria Arrector pili muscle Pulls on follicle, forcing the hair to stand up Cold or emotional states- goosebumps

Anatomy of a Single Hair Figure 5.9

Hair Follicles and Hair

Hair Follicles Figure 5.10a-c

Hair Color Produced by melanocytes at the hair papilla

Function of Hair Head Nostrils, ears, and eyes Sensory Protection from UV light Cushion a light blow to head Insulation Nostrils, ears, and eyes Prevent entry of particles Sensory Sensory nerve fiber at base of every hair

Exocrine Glands- Reach Outside Sebaceous glands (Oil glands) Associated with hair Secrete sebum, which lubricates and inhibits bacteria growth Acne- condition when they are clogged Sweat glands (Watery Glands) 2 kinds 1- hormonal- armpits, groin, nipples 2- All over body

Sebaceous Glands and Hair Figure 5.11

Sweat Glands

Figure 5.12 Sweat Glands Figure 5.12a, b

Nails Keratinized cells that protects the tips of fingers and toes

Structures Nail Body Nail Root Cuticle Covers an area of the epidermis called the nail bed Nail Root Where nail production occurs Not visible on surface Cuticle Portion of stratum corneum

Structure Contd. Lunula Pale crescent area near the root were blood vessels are absent

Figure 5.13 The Structure of a Nail

Copyright © 2010 Pearson Education, Inc. The Skeletal System The Skeletal System provides structural support The Integumentary System synthesizes vitamin D3, essential for calcium and phosphorus absorption (bone maintenance and growth) Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc. The Muscular System The Muscular System’s facial muscles pull against skin of face, producing expressions important in communication The Integumentary System synthesizes vitamin D3 , essential for normal calcium absorption (calcium ions play an essential role in muscle contraction) Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc. The Nervous System The Nervous System controls blood flow and sweat gland activity for thermoregulation; stimulates contraction of arrector pili muscles to elevate hairs The Intergumentary System’s receptors in dermis and deep epidermis provide sensations of touch, pressure, vibration, temperature, and pain Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc. The Endocrine System The Endocrine System includes the sex hormones that stimulate sebaceous and apocrine gland activity, and develop secondary sexual characteristics; suprarenal hormones alter blood flow to skin and mobilize lipids from fat cells The Integumentary System synthesizes vitamin D3, precursor of calcitriol, a hormone produced by the kidneys Copyright © 2010 Pearson Education, Inc.

The Cardiovascular System The Cardiovascular System provides oxygen and nutrients; delivers hormones and cells of immune system; carries away carbon dioxide, waste products, and toxins; provides heat to maintain normal skin temperature The Integumentary System’s mast cells produce localized changes in blood flow and capillary permeability Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc. The Lymphatic System The Lymphoid System assists in defending the integument by providing additional macrophages and mobilizing lymphocytes The Integumentary System provides physical barriers that prevent pathogen entry; macrophages resist infection; mast cells trigger inflammation and initiate the immune reponse Copyright © 2010 Pearson Education, Inc.

The Respiratory System The Respiratory System provides oxygen and eliminates carbon dioxide The Integumentary System’s hairs guard entrance to nasal cavity Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc. The Digestive System The Digestive System Provides nutrients for all cells and lipids for storage by adipocytes The Integumentary System synthesizes vitamin D3, needed for absorption of calcium and phosphorus Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc. The Urinary System The Urinary System excretes waste products, maintains normal body fluid pH and ion composition The Integumentary System assists in elimination of water and solutes; keratinized epidermis limits fluid loss through skin Copyright © 2010 Pearson Education, Inc.

The Reproductive System The Reproductive System’s sex hormones affect hair distribution, adipose tissue distribution in subcutaneous layer, and mammary gland development The Integumentary System covers external genitalia; provides sensations that stimulate sexual behaviors; mammary gland secretions provide nourishment for newborn infant Copyright © 2010 Pearson Education, Inc.