Anatomy & Physiology Chp 4

Santucci's lecture notes

Functions of body membranes

cover body surfaces
line body cavities
form protective sheets around organs

tissue types of membranes

epithelial, connective tissue

Epithelial membranes

cutaneous, mucous, serous

cutaneous (skin) membrane

dry membrane, outermost protective boundary

Mucous Membranes

surface epithelial type depends on site:
stratified squamous epithelial (mouth, esophagus)
simple columnar epithelial (rest of digestive tract);
moist membranes adapted for absorption or secretion; underlying loose connective tissue (lamina propria)

Lamina propria

underlying loose (areolar) connective tissue

Where are mucous membranes located?

all body cavities that open to the exterior body surface

Serous membranes

-Surface simple squamous epithelium.

-Underlying thin layer areolar connective tissue.

-Lines open body cavities that are closed to the exterior of the body.

-Serous layers occur in pairs separated by serous fluid.

Visceral layer

covers outside of organ

parietal layer

lines portion of wall of ventral body cavity

Specific serous membranes

peritoneum, pleura, pericardium

Peritoneum

abdominal cavity

Pleura

around the lungs

pericardium

around the heart

connective tissue membrane

synovial membrane

synovial membrane

lines fibrous capsules surrounding joints (bursae, tendon sheaths)

secretes a lubricating fluid

Parts of Integumentary system

skin, and skin derivatives (hair, nails, glands)

Skin functions

protects deeper tissues from:
mechanical damage (bumps)
chemical damage (acids/bases)
bacterial damage
UV radiation
Thermal damage
desiccation (drying out)

Keratin

hard protein material found in the epidermis, hair, and nails that protects skin from water loss

Other Skin functions

aids in loss or retention of body heat

aids in excretion of urea and uric acid

synthesizes vitamin D

cutaneous sensory receptors detect touch, temperature, pressure, and pain

Epidermis

outer layer of skin; stratified squamous epithelium; cornified or keratinized to prevent water loss; avascular; most cells are keratinocytes

Dermis

dense connective tissue; contains blood vessels which play a role in body temperature regulation; collagen fibers give skin toughness; elastic fibers give skin elasticity; nerve supply sends messages to the central nervous system

hypodermis

the subcutaneous tissue just deep to the skin made up of mostly adipose tissue that serves as a shock absorber and insulates deeper tissues

How long does it take for the outer layer of skin to shed?

27 days

Layers of the Epidermis

4-5 layers: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

Come, Let's Get Sun Burned

corneum, lucidum, granulosum, spinosum, basale

come

corneum

Let's

lucidum

Get

Granulosum

Sun

spinosum

Burned

basale

Stratum basale

deepest layer of epidermis; lies next to dermis; wavy borderline with the dermis anchors the 2 together; cells undergoing mitosis; daughter cells are pushed upward to become the more superficial layers

Stratum spinosum

live keratinocytes connected by desmosomes produce pre-keratin

Stratum granulosum

cells are flattened; organelles are deteriorating; cytoplasm full of granules

Stratum Lucidum

only found in thick hairless skin (palms of hand, soles of feet); formed from dead cells of deeper strata

Stratum Corneum

outermost layer of epidermis; shingle-like dead cells ae filled with keratin; glycolipids in extracellular space

Melanin

pigment produced by melanocytes; color is yellow to brown to black; accumulates in membrane-bound granules called melanosomes; amount produced depends upon genetics and exposure to sunlight

Melanocytes

cells that produce melanin; mostly found in the stratum basale

Epidermal dendritic cells

located in the stratum spinosum; alert and activate immune cells to a threat

Merkel Cells

associated with sensory nerve endings; serve as touch receptors called Merkel discs

Layers of Dermis

2; papillary layer; reticular layer

Papillary layer

upper dermal region; contains projections called dermal papillae

Dermal papillae

projections that cause fingerprints; some contain capillary loops; others house pain receptors and touch receptors

fingerprints

identifying films of sweat

Reticular layer

lower dermal region; contains blood vessels, sweat and oil glands, deep pressure receptors

lamellar corpuscles

deep pressure receptors

Pigments that contribute to skin color

3; melanin, carotene, hemoglobin

carotene

orange-yellow pigment from some vegetables

Hemoglobin

red coloring from blood cells in dermal capillaries

Oxygen content determines the extent of red coloring

Erythema

redness due to embarrassment, inflammation, hypertension, fever, or allergy

Pallor

blanching due to emotional stress (ex: fear), anemia, low blood pressure, impaired blood flow to an area

Jaundice

yellowing caused by liver disorder

What happened to Santucci’s grandson?

jaundice; treated with blue light

Hematomas

bruises; black and blue marks

Cutaneous glands

exocrine glands: sebaceous glands; sweat glands

Appendages of the skin

cutaneous glands; hair; hair follicles; nails

sebaceous glands

excrete sebum; most have ducts that empty into hair follicles; others open directly onto skin surface; activate at puberty

Sebum

oil and cell fragments; lubricant for skin; prevents brittle hair; kills bacteria

Sweat (sudoriferous) glands

eccrine; apocrine; produce sweat; widely distributed in skin

Eccrine glands

produce sweat to cool off; open via duct to pore on skin surface

Sweat Composition

mostly water; salts and vitamin C; metabolic waste

Sweat Function

helps dissipate excess heat; excretes waste products; acidic nature inhibits bacteria growth; odor is from associated bacteria

Apocrine glands

ducts empty into hair follicles; activate at puberty; release sweat that contains fatty acids and proteins and is milky or yellowish in color

Hair

produced by hair follicle; root enclosed in follicle; consists of hard keratinized epithelial cells; pigmented by melanin; grows in the hair bulb matrix in stratum basale

Hair shaft

part of hair that projects from the surface of the scalp or skin

Hair anatomy (from inside out)

central medulla; cortex surrounds medulla; cuticle on outside of cortex (most heavily keratinized region of the hair)

Hair follicle

dermal and epidermal sheath surround hair root

Arrector pili muscle

smooth muscle; pulls hair upright when person is cold or frightened

Nails

scale-like modifications of the epidermis; heavily keratinized; stratum basale extends beneath the nail bed; lack of pigment makes them colorless

Nail structures

free edge; body is the visible attached portion; nail folds are skin folds that overlap the edges of the nail; growth occurs form nail matrix; root of nail is embedded in skin

Nail cuticle

proximal nail fold that projects onto the nail body

Burns

tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals; result in loss of body fluids and invasion of bacteria

Danger of Burns

dehydration; electrolyte imbalance; circulatory shock

Rule of Nines

way to determine extent of the burns; divides body into 11 areas for quick estimation; each area represents about 9% of total body surface area

Perineum (genitals)

accounts for 1% of body in rule of nines

Anterior trunk

18% in rule of nines

Anterior Legs

9% each in rule of nines

First Degree burn

partial-thickness burn; only epidermis is damaged; skin is red and swollen

Second degree burn

partial thickness burn; epidermis and upper dermis are damaged; skin is red with blisters

Third degree burn

full-thickness burn; destroys entire skin layer; burn area is painless; requires skin grafts; burn is gray-white or black

Critical Second-degree burns

more than 25% of body

Critical third-degree burns

more than 10% of body; burns on face, hands, or feet

Ahtlete’s foot

tinea pedis; caused by fungal infection

Boils and Carbuncles

caused by bacterial infection

Cold sores

caused by herpes virus

Contact dermatitis

exposures cause allergic reaction

Impetigo

caused by bacterial infection

Psoriasis

cause unknown; triggered by trauma, infection, stress

decubitus ulcer

bed sore

Cancer

abnormal cell mass

Benign

does not spread (encapsulated)

Malignant

metastasizes (moves) to other parts of the body

Skin cancer

most common type of cancer; major threat to skin exposed to excessive sunlight

Basal cell carcinoma

least malignant skin cancer; most common; arises from the stratum basale

Squamous cell carcinoma

Metastasizes to lymph nodes if not removed

Early removal allows a good chance of cure

Believed to be sun-induced

Arises from stratum spinosum

Malignant melanoma

most deadly skin cancer; cancer of melanocytes; metastasizes rapidly to lymph and blood vessels; detection uses ABCD(e) rule

ABCD(e) Rule

Used to detect cancerous tumors

A

Asymmetry; 2 sides of pigmented mole don’t match

B

Border irregularity; borders of mole are not smooth

C

Color; different colors in pigmented area