Chapter 4: Integumentary System

Entry Task 1/7

Brainstorm AND record 3 possible functions of the integumentary (skin) system…

Wednesday 1/7

Mini-Quiz: Body Tissues

Begin CH 4: Skin & Body Membranes– Worksheet: Skin Structure

Take notes from PowerPoint– Integumentary System

Function Melanin p.108-114

Skin & Body Membranes

Epithelial tissue membrane (3 types)– Cutaneous

Stratified squamous on a layer of dense fibrous connective tissue

– MucousStratified squamous on simple

columnar– Serous

Simple squamous on areolar tissue

A Closer Look at the Serosa…

Parietal layer– lines ventral cavity, folds on itself to form visceral

layer

Visceral layer– covers outside of organs in cavity– Serous fluid fills the pocket

The Serosa

Skin & Body Membranes, cont…

Connective tissue membranes– Synovial

Soft areolar connective tissue

NO epithelial cells

Functions of I.S.

Protects from:– Mechanical, chemical, bacterial, UV, thermal, &

dessication

Heat loss/retention Excretion of urea/uric acid Makes Vitamin D Tells us about external environment

Structure

Epidermis– Stratified squamous

Dermis– Dense fibrous conn. tissue

Hypodermis– Adipose tissue

Firmly connected together!

Skin Structure

Epidermis

5 layers called “strata” (deep to superficial)– stratum basale – stratum spinosum– stratum granulosum – stratum lucidum– stratum corneum

Avascular—no blood supply Keratinocytes—produce keratin

Epidermis of Thick Skin

A Closer Look at the Strata…

Stratum basale– deepest layer– receives nutrients– constantly dividing

Stratum spinosum Stratum granulosum

– Cells become flatter, full of keratin Stratum lucidum

– Cells beginning to die, extra thick, hairless skin Stratum corneum

– DEAD!!!– 20-30 cell layers thick

Fun Facts

Every 25-45 days, you have a completely NEW epidermis!

Everything you see when you look at someone else is DEAD! Gross!

Melanin

Melanin is a pigment– yellow to brown to black– Melanocytes make the pigment

Freckles/moles – Melanin is concentrated in 1 area

Dermis

Your dermis is your “hide”– Strong, stretchy envelope– Dense fibrous conn. tissue

Collagen Elastic fibers

– 2 Regions: Papillary layer—upper dermis

– House pain receptors/free nerve endings & touch receptors (Meissner’s corpuscles)

Reticular layer—deepest skin layer– Pressure receptors (Pacinian corpuscles)

Dermis, continued…

Blood Vessels—maintain homeostasis Rich nerve supply

Entry Task 1/8

1. Explain the function of the stratum basale of the epidermal layer.

2. Why do we get wrinkled, saggy skin as we age? Be sure to identify the layer of skin involved in your answer.

3. What part of skin do you think pain receptors are found in? Touch receptors?

Tuesday 3/25

Explore the function of cutaneous receptors through a series of lab activities!

Review Entry Task Complete Cutaneous Receptors lab activity!

HW: Read p. 116-124

Wednesday 3/26

Finish “Cutaneous Receptors” Activity

Activity: Make a Sweat Map!

PowerPoint covering p.116-124– Take notes!!!

Skin Color

3 Pigments– Melanin– Carotene– Oxygen-rich hemoglobin

Alterations in skin color– redness/erythema– pallor/blanching– jaundice– bruises

Appendages of the Skin

Includes:– cutaneous glands, hair, hair follicles, and nails

Exocrine glands—release secretions through ducts– 2 Types

Sebaceous glands (oil) Sudoriferous glands (sweat)

Sebaceous Glands (Oil)

All over skin (not on palms/feet) Empties into hair follicles Secretes sebum—oil & fragmented cells

– Keeps skin soft– Has chemicals that kill bacteria– Clogged duct = whitehead

Sudoriferous Glands (sweat)

2.5 million/person 2 Types: Eccrine & Apocrine

Eccrine– More common, produces sweat– Heat regulation– 7L sweat on a hot day!

Sudoriferous Glands, cont…

Apocrine– Mainly in axillary & genital area– Larger than eccrine glands– Secretes fatty acid/protein along with other

components– Bacteria have a hay day!!!

Hair & Hair Follicles

Components:– Follicle: produces hair– Shaft: part of hair exposed to environment– Root: part of hair enclosed in the follicle– Medulla: central core– Cortex: area between medulla & cuticle– Cuticle: heavily keratinized; shingles– Arrector pili: smooth muscle, connects follicle to

tissue– Matrix: growth zone– Hair bulb: contain melanocytes

Nails

Components:– Free edge– Body– Root: embedded in skin– Nail folds: sides of nails, connected to skin– Cuticle: thick proximal nail fold– Lanula: crescent– Nail bed: extends beneath the nail– Nail matrix: thick part of nail bed; growth

Homeostatic Imbalances

Over 1000 ailments of the skin!– Mostly allergies, fungus, burns, & cancer

Athlete’s foot—fungus Boils/carbuncles—inflamed oil glands Cold sores—herpes virus Contact dermatitis—chemical contact Impetigo—bacterial infection Psoriasis—autoimmune disorder

Burns

Def: Tissue damage/cell death caused by intense heat

Skin = thick as a paper towel Almost all body systems suffer when skin is

burned

2 life threatening problems: fluid loss & kidney shutdown/circulatory shock

Burns, cont…

Rule of Nines:– Body divided into 11 areas, each covering 9%

surface area– Helps determine volume of fluid lost

Infection is leading cause of death Burns are sterile 24 hours after

– Then pathogens invade

Burn Classification

1° Burn– Epidermis damaged– Red, swollen– Lasts 2-3 days– EX: sunburn

Burn Classification

2° Burn– Epidermis & Upper

Dermis damaged– Red, painful blisters– Regrowth can occur– No permanent

scarring if taken care of

Burn Classification

3° Burn– Entire thickness of

skin destroyed– Blanched/Black– No pain—nerves

destroyed– Regeneration not

possible– Skin grafting

Burn Classification

CRITICAL burns meet this criteria:

– 25+% of the body has 2° burns– 10% has 3° burns– 3° burns on the face, hands, and/or feet

Skin Cancer

Most common of all cancers 1 in 5 people will have skin cancer in their

lifetime

3 Types– Basal cell carcinoma– Squamous cell carcinoma– Malignant melanoma

Basal Cell Carcinoma

Least malignant, most common

No keratin/boundary formed by stratum basale

Invades dermis/hypodermis

On face, shiny, slow-growing

Full cure @ 99% in most cases

Squamous Cell Carcinoma

Stratum spinosum Scaly, reddened papule Shallow ulcer, raised

border Scalp, ears, hands, lips Fast growing If caught early full

recovery can be made

Malignant Melanoma

Cancer of melanocytes 5+% cases are

melanoma Appears

spontaneously, develops from pigmented moles

brown to black patches 50% survival rate

ABCD Rule

Asymmetry– 2 sides of mole/spot don’t match

Border irregularity– Borders not smooth, have indents

Color– Different colors, range from black/brown/tan,

blues/reds

Diameter– 6+ mm

Thursday 3/27

Finish PowerPoint Notes Begin Review assignment

– P.127 MC: #1-2, 4, 6-7; SA: #1-4, 6-11, 13;

At the Clinic: #1-4

Identify different types of burns and skin cancers

Friday 3/28

Correct Review

Play Flyswatter Review game

Test over all of CH 4 on Monday after break!

Have a Great Spring Break!