warm up why is your skin important for your body to maintain homeostasis?

Warm Up

• Why is your skin important for your body to maintain homeostasis?

Skin and Body Membranes

Chapter 4 (p.110-127)

Objective Checklist

List the structure (tissue type) and functions of each membrane and give its location in the body

Name the layers of the integumentary system and list characteristics of each

Differentiate between 1st, 2nd, and 3rd degree burns

Describe three different types of skin cancer

Skin and Body Membranes

• Body membranes line, protect, and lubricate

• Types of Membranes include…– Epithelial membranes

(cutaneous, mucous, and serous)

– Connective tissue membranes

Cutaneous Membrane

• Cutaneous membrane (skin)– Keeps your dry!– Outermost protective boundary

• Components– Epidermis (keratinized stratified squamous

epithelium)– Dermis (dense connective tissue)– Hypodermis (adipose tissue)• Not considered part of the skin• Anchors skin to underlying organs

Cutaneous Membrane

Mucous Membranes

• Components– squamous/columnar

epithelium (surface)– areolar connective tissue

(underneath)

Figure 4.1b

• Lines all body cavities that open to the exterior body surface (respiratory, digestive, urinary, and reproductive tracts)

• Moist and adapted for absorption or secretion

Review

Why do you need stratified squamous tissue in your mouth?

Why do you need simple columnar tissue in your stomach, intestines?

Why do you need pseudostratified columnar tissue in your trachea?

Why do you need transitional squamous tissue in your bladder?

Serous Membranes

• Composition – simple squamous

epithelium (surface)– areolar connective tissue

(beneath)

• Lines open body cavities that are closed to the exterior of the body

Figure 4.1c

• Serous layers separated by serous fluid

Serous Membranes• Examples of serous membranes– Peritoneum (abdominal cavity)– Pleura (around lungs)– Pericardium (around heart)

Figure 4.1d

Why is there serous fluid between the two layers??

What do you call the OUTTER membrane that surrounds the HEART?

Connective Tissue Membrane(Synovial Membrane)

• Components– Areolar connective

tissue• Lines fibrous capsules

surrounding joints• Cells there secrete

lubricating fluid

Figure 4.2

Why do you want lubricating fluid in this area?

Now a Closer Look at Skin

Skin Derivatives

• Skin derivatives– Sweat glands– Oil glands– Hairs– Nails

Other Skin Functions• Protects deeper tissues from:– Mechanical damage– Chemical damage– Bacterial damage– Thermal damage– Ultraviolet radiation– Desiccation

• Aids in heat regulation• Aids in excretion of urea and uric acid• Synthesizes vitamin D

Skin Structure in Detail• The epidermis is avascular and

obtains nutrients from the dermal layer

• The dermis contains blood vessels, nerves, sweat glands, and oil glands

• It also contains dermal papillae that form ridges on the surface of the skin

Skin Structure in Detail

Normal Skin Color Determinants

• Melanin– Yellow, brown or black

pigments• Carotene– Orange-yellow pigment

from some vegetables• Hemoglobin– Red coloring from blood

cells in dermis capillaries

Appendages of the Skin

• Sebaceous glands– Produce oil• Lubricant for skin• Kills bacteria

– Most with ducts that empty into hair follicles

– Glands are activated at puberty

Appendages of the Skin

• Sweat glands– Two types• Eccrine

– Open via duct to pore on skin surface– Widely distributed– Used in thermoregulation

• Apocrine– Opening associated with hair follicles– Located in axillary and pubic regions– Precise function unknown

Bacteria

Bacteria

Appendages of the Skin• Hair– Consists of hard

keratinized epithelial cells

– Melanocytes provide pigment for hair color

– Muscles around the root contract when you are cold

Why does your body do that??

Appendages of the Skin• Nails– Scale-like modifications of the

epidermis– Heavily keratinized

How much bone would need to be removed for your nail to never grow back?

Burns• Tissue damage and cell death caused by

heat, electricity, UV radiation, or chemicals• Associated dangers– Dehydration– Electrolyte imbalance– Circulatory shock– Infection

Why are dehydration, electrolyte imbalance, and circulatory shock related?

What is circulatory shock?

Rule of Nines

• Way to determine the extent of burns

• Body is divided into 11 areas for quick estimation

• Each area represents about 9%

Figure 4.11a

Severity of Burns• First-degree– Only epidermis is damaged– Skin is red and swollen

• Second degree– Epidermis and upper dermis

are damaged– Skin is red with blisters

• Third-degree– Destroys entire skin layer– Burn is gray-white or black

Critical Burns

• Burns are considered critical if:– Over 25% of body has second degree burns– Over 10% of the body has third degree burns– There are third degree burns of the face, hands, or

feet (suffocation and/or loss of function)

Skin Cancer Types• Basal cell carcinoma– Least malignant, most common– Dome shaped w/ pearly appearance

• Squamous cell carcinoma– Metastasizes to lymph nodes– Early removal allows a good chance of

cure– Shallow ulcer with firm, raised border

• Malignant melanoma– Most deadly of skin cancers– Metastasizes rapidly to lymph and blood

vessels

ABCD Rule for Melanoma

• A = Asymmetry– Two sides of pigmented mole do not match

• B = Border irregularity– Borders of mole are not smooth

• C = Color– Different colors in pigmented area

• D = Diameter– Spot is larger then 6 mm in diameter

ABCD Rule for Melanoma

Objective Checklist

List the structure (tissue type) and functions of each membrane and give its location in the body

Name the layers of the integumentary system and list characteristics of each

Differentiate between 1st, 2nd, and 3rd degree burns

Describe three different types of skin cancer