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

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 membraneEpidermisDermis

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 keratinThin 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:

Stratum basale/ germinativum Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum

From deep…….

…… to superficial

The Structure of the Epidermis

Figure 5.4

Epidermis Cell Layers Germinative

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

Interrupted blood supply leads to cyanosis- blue!

CaroteneOrange-yellow pigment found in orange vegetables

MelaninYellow-brown pigmentProtects us from UV radiationProduced 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 factorGrowthDivisionRepairSecretion

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 layerDeep reticular layer

Layers of the Dermis

Papillary layerAreolar tissueContains blood vessels, lymphatics, sensory

nerves of epidermis

Reticular layerDense irregular connetive tissueContains 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

Connective tissue containing capillaries and nerves

RootAnchors hair into skin

ShaftPart we see on the surfaceConsists of three layers

○ Cuticle- overlapping shingle layer○ Cortex- underlying layer- pigments○ Medulla- core of hair

Structures Contd.

Sebaceous GlandsDischarge oily substance into hair folliclesInhibits growth of bacteria

Arrector pili musclePulls on follicle, forcing the hair to stand upCold 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

Protection from UV lightCushion a light blow to headInsulation

Nostrils, ears, and eyesPrevent entry of particles

SensorySensory nerve fiber at base of every hair

Exocrine Glands- Reach Outside

Sebaceous glands (Oil glands)Associated with hairSecrete sebum, which lubricates and inhibits

bacteria growthAcne- 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

Covers an area of the epidermis called the nail bed

Nail RootWhere nail production occursNot visible on surface

CuticlePortion of stratum corneum

Structure Contd.

LunulaPale crescent area near the root were blood

vessels are absent

Figure 5.13 The Structure of a Nail

Figure 5.13

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.

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)


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


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


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


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


The Respiratory System

• The Respiratory System provides oxygen and eliminates carbon dioxide

• The Integumentary System’s hairs guard entrance to nasal cavity


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


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


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


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

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