Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Seventh Edition Elaine N. Marieb Chapter 4 Skin and Body Membranes

Skin and Body Membranes Slide 4.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Function of body membranes  Line or cover body surfaces  Protect body surfaces  Lubricate body surfaces

Classification of Body Membranes Slide 4.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Epithelial membranes  Cutaneous membrane  Mucous membrane  Serous membrane  Connective tissue membranes

Cutaneous Membrane Slide 4.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cutaneous membrane = skin  A dry membrane  Outermost protective boundary  Superficial epidermis  Keratinized stratified squamous epithelium  Underlying dermis  Mostly dense connective tissue Figure 4.1a

Mucous Membranes Slide 4.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Surface epithelium  Type depends on site  Underlying loose connective tissue (lamina propria)  Lines all body cavities that open to the exterior body surface  Often adapted for absorption or secretion Figure 4.1b

Serous Membranes Slide 4.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Surface simple squamous epithelium  Underlying areolar connective tissue  Lines open body cavities that are closed to the exterior of the body  Serous layers separated by serous fluid Figure 4.1c

Serous Membranes Slide 4.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Specific serous membranes  Peritoneum  Abdominal cavity  Pleura  Around the lungs  Pericardium  Around the heart Figure 4.1d

Connective Tissue Membrane Slide 4.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Synovial membrane  Connective tissue only  Lines fibrous capsules surrounding joints Figure 4.2

Integumentary System Slide 4.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Skin (cutaneous membrane)  *Skin derivatives  Sweat glands  Oil glands  Hairs  Nails

Just what does the skin Do?

Skin Functions Slide 4.9a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Protects deeper tissues from:  Mechanical damage  Chemical damage  Bacterial damage  Thermal damage  Ultraviolet radiation  Desiccation

Skin Functions Slide 4.9b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Aids in heat regulation  *Aids in excretion of urea and uric acid and NaCl  *Synthesizes vitamin D

Skin Structure Slide 4.10a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Epidermis – outer layer  Stratified squamous epithelium  Often keratinized (hardened by keratin)  *Dermis – inner layer  Dense connective tissue

Skin Structure Slide 4.10b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Deep to dermis is the hypodermis  Not part of the skin  Anchors skin to underlying organs  *Composed mostly of adipose tissue  Stores fat

Layer of Epidermis Slide 4.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Strata – layers  You do not need to know! Rejoice!  Stratum basale - single layer of columnar cells that undergo mitosis

Melanin Slide 4.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Pigment (melanin) produced by melanocytes  *Protects from UV light  Color is yellow to brown to black  *Melanocytes are mostly in the stratum basale  *Amount of melanin produced depends upon genetic and exposure to sunlight

SKIN COLOR Freckles - patches of melanin Albinism - inability to produce melanin in skin, eyes and hair Vitiligo - partial or complete loss of melanin in an area

Stratum Corneum *outermost epidermal layer Barrier to pathogens, chemicals Prevents entry of water, prevents most evaporation Outermost layers of dead cells what is left is their *keratin-waterproof protein layers of flat dead cells containing keratin which waterproofs and toughens the skin

Subcutaneous layer - contains areolar C.T. and adipose tissue; responsible for female body contours; aka - superficial fascia or hypodermis; attaches dermis to underlying organs -bones and muscles

Dermis *irregular type of fibrous connective tissue: - fibroblast produce collagen and elastin Strength & elasticity

Dermis Slide 4.13a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Two layers  Papillary layer-junction of the dermis/epidermis  *Pain receptors  *Capillary loops-nourish the epidermis  Accessory skin structures found here.

Receptors Cutaneous senses- sensitivity determined by how many receptors-heat, cold, pain, pressure, touch Provide CNS with information of external enviornment ( this information formulates a response) *free nerve endings- pain heat and cold Encapsulated nerve endings- touch and pressure

Reality is what we perceive, but what we perceive is not always reality!

-In order to "feel" a sense, you need: *A Stimulus *A Receptor *A Conduction to the brain (carried all the way through) *An interpretation of the impulse

Skin Structure Slide 4.13b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.4

Appendages of the Skin Slide 4.15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Sebaceous glands (all over except palms and soles of feet)- secrete sebu  *Produce oil  *Lubricant for skin  *Kills bacteria  Most with ducts that empty into hair follicles  Glands are activated at puberty  *Acne – active infection of sebaceous glands

Ceruminous glands- cerumen (ear wax)

Appendages of the Skin Slide 4.16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Sweat glands  Widely distributed in skin  Two types  Eccrine  Open via duct to pore on skin surface  Apocrine  Ducts empty into hair follicles  *which are concerned with maintaining body temp?

Sweat (sudoriferous) Apocrine - begin to function at puberty; contain organic substances which produce an odor when broken down; open into hair follicles

Sweat and Its Function Slide 4.17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Composition  Mostly water  Some metabolic waste  Fatty acids and proteins (apocrine only)  *Function  Helps dissipate excess heat  Excretes waste products  Acidic nature inhibits bacteria growth  Odor is from associated bacteria

Appendages of the Skin Slide 4.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Hair  Hair root at base- mitosis  Color from melanin  Hair shaft- dead cells- keratin Figure 4.7c

Associated Hair Structures Slide 4.20 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Hair follicle  Pilomotor or  Arrector pilli (goose pumps) (traps air- insulate)  Smooth muscle Figure 4.7a

HAIR Hair loss - normal in the scalp -> hairs per day. Hair goes thru growth and rest periods. Color is mainly due to melanin; blond and red hair contains iron and sulfur The average lifespan for a strand of hair is 5 and ½ yars lifespan of an eyelash is approximately 150 days.

Nail Structures Slide 4.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Free edge &  Body  Root of nail- (mitosis)  Heavily keratinized  *Protect, enable to pick up objects Figure 4.9

Blood vessels Capillaries Arteriolies-small arteries Vasodilation- dilate, bring blood close to body surface, heat escapes Vasoconstriction constrict to cold- conserve body heat Stressful situation? Dilate or constrict

subcutaneous tissue Connects dermis to underlying muscles contains WBC’s to destroy pathogens entering thru breaks in the skin Stores fat Cushions Insulates Contributes to appetite

Skin Homeostatic Imbalances Slide 4.23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Infections  Athletes foot  Caused by fungal infection  Boils and carbuncles  Caused by bacterial infection  Cold sores  Caused by virus

Athlete’s Foot

Boils Cold Sores

Skin Homeostatic Imbalances Slide 4.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Infections and allergies  Contact dermatitis  Exposures cause allergic reaction  Impetigo  Caused by bacterial infection  Psoriasis  Cause is unknown  Triggered by trauma, infection, stress

Impetigo Psoriasis

Skin Homeostatic Imbalances Slide 4.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Burns  Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals  Associated dangers  *Dehydration  Electrolyte imbalance  Circulatory shock

Rules of Nines Slide 4.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Way to determine the extent of burns  Body is divided into 11 areas for quick estimation  Each area represents about 9%  Pg. 92 textbook

Severity of Burns Slide 4.27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  First-degree burns  Only epidermis is damaged  Skin is red and swollen  Second degree burns  Epidermis and upper dermis are damaged  *Skin is red with blisters  Third-degree burns  Destroys entire skin layer  Burn is gray-white or black

Critical Burns Slide 4.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  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

Skin Cancer Slide 4.29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  *Cancer – abnormal cell mass  Two types  *Benign  Does not spread (encapsulated)  *Malignant  Metastasized (moves) to other parts of the body  *Skin cancer is the most common type of cancer

Skin Cancer Types Slide 4.30 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Basal cell carcinoma  Least malignant  Most common type  Arises from statum basale  Squamous cell carcinoma  Arises from stratum spinosum  Metastasizes to lymph nodes  Early removal allows a good chance of cure

Basal Cell Carcinoma

Malignant Melanoma

Skin Cancer Types Slide 4.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Malignant melanoma  Most deadly of skin cancers  Cancer of melanocytes  Metastasizes rapidly to lymph and blood vessels  Detection uses ABCD rule

ABCD Rule Slide 4.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  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

Epidermis Dermis Subcutaneous Accessory structures functions