The Skin Flashcards
What do the functions of the epidermis help protect people from?
- Loss of Fat-Loss of heat
- Loss of elasticity
- Thinning
- Decrease in blood flow/coloring
- Bruise easier
- Drying: “Gray” loss of hair (starts at age 50)
How to protect yourself from aging
- Eating nutritiously
- Hydrate
- Exercise
- 8 hours of sleep
Function of Body Membranes
- Cover body surfaces
- Line body cavities
- Form protective sheets around organs
Classifications of Body Membranes
- Epithelial membranes
- Cutaneous membranes
- Mucous membranes
- Serous membranes
- Connective tissue membranes
- Synovial membranes
Cutaneous Membrane (Type of Epithelial Membrane)
- Cutaneous Membrane= skin
- Dry membrane
- Outermost protective boundary
- Superficial (outermost) epidermis is composed of keratinized stratified squamous epithelium
- Underlying dermis is mostly dense connective tissue
Mucous Membrane (Type of Epithelial Membrane)
- Surface epithelium type depends on site
- Stratified squamous epithelium (mouth, esophagus)
- Simple columnar epithelium (rest of digestive system)
- Underlying loose connective tissue (lamina propria)
- Lines all body cavities that open to the exterior body surface
- Often adapted for absorption or secretion
Serous Membrane
- Surface is a layer of simple squamous epithelium
- Underlying layer is a thin layer of areolar connective tissue
- Lines open body cavities that are closed to the exterior of the body
- Serous membranes occur in pairs separated by serous fluid
- Visceral layer covers the outside of the organ
- Parietal layer lines a portion of the wall of ventral body cavity
- (Visceral lines organ, Parietal lines cavity)
Visceral Layer vs. Parietal Layer
- Visceral layer covers the outside of the organ
- Parietal layer lines a portion of the wall of ventral body cavity
- (Visceral lines organ, Parietal lines cavity)
Specific Serous membranes
- Peritoneum
- Abdominal Cavity- Pleura
- Around the lungs
- Pericardium
- Around the heart
- Pleura
Synovial Membrane (Type of Connective Membrane)
- Connective tissue only
- Lines fibrous capsules surrounding joints
- Secretes a lubricating fluid
Integumentary System
- Skin (cutaneous membrane)
- Skin derivatives
- Sweat glands
- Oil glands
- Hair
- Nails
Skin Structure
- Epidermis– Outer Layer
- Stratified squamous epithelium
- Often keratinized (hardened by keratin)
- Dermis
- Dense connective tissue
- Subcutaneous tissue (hypodermis) is deep to dermis
- Not part of the skin
- Anchors skin to underlying organs
- Composed mostly of adipose tissue
Layers of the Epidermis
- Stratum Basale (Stratum germinativum)
- Deepest
- Stratum Spinosum and Stratum Granulosum
- 2nd Deepest
- Stratum Lucidum (ONLY ON PALMS OF HANDS AND SOLES OF FEET)
- Stratum Corneum
- Outermost Layer of Epidermis
Stratum Basale
- Deepest layer of the epidermis
- Lies next to the dermis
- Cells undergoing mitosis
- Daughter cells are pushed upward to become more superficial layers
Stratum Spinosum and Stratum Granulosum
- Fluid maintains life
- Solvent
- Temperature
- Pressure
- Transport
Stratum Lucidum
- Formed from dead cells of the deeper strata
- Occurs only in thick, hairless skin of the palms of hands and soles of feet
Stratum Corneum
- Outermost layer of epidermis
- Shingle-like dead cells are filled with keratin (protective protein prevents water loss from skin)
Summary of Epithelial Layers from Deepest to most superficial
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum (think, hairless skin only)
- Stratum corneum
Melanin
- Pigment (melanin) produced by melanocytes
- Melanocytes are mostly in the stratum basale
- Color is yellow to brown to black
- Amount of melanin produced depends upon genetics and exposure to sunlight
- Everyone has the same amount of melanocytes, some people’s produce more melanin than others
Overall Dermis Structure
- Collagen and elastic fibers located throughout the dermis
- Collagen fibers give skin its toughness
- Elastic fivers give skin elasticity- Blood vessels play a role in body temperature regulation (dilation & constriction which is controlled by the nervous system)
Layers of the Dermis
- Papillary Layer
- Reticular Layer
Papillary Layer
- Upper dermal region
- Projections called dermal papillae (finger prints)
- Some contain capillary loops
- Other house pain receptors and touch receptors
Reticular Layer
- Deepest skin layer
- Blood vessels
- Sweat and oil glands
- Deep pressure receptors
Skin Color Determinants
- Melanin
- Yellow, brown, or black pigments
- Carotene
- Orange-yellow pigment from some vegetables
- Hemoglobin
- Red coloring from blood cells in dermal capillaries
- Oxygen contents determine the extent of red coloring
Cutaneous Glands
- all exocrine glands
- Sebaceous glands
- Sweat glands- sudoriferous is the scientific name
Sebaceous Glands
- Produce oil (sebum)
- Lubricant for skin
- Prevents brittle hair
- Kills bacteria- Most have ducts that empty into hair follicles; others open directly onto skin surface
- Glands are activated at puberty
Sweat Glands
- sudoriferous is the scientific name
- Produce sweat
- Widely distributed in skin
- Two types
- Eccrine:
- Open via duct to pore on skin surface
- Apocrine
- Ducts empty into hair follicles
- Eccrine:
Hair
- Produced by hair follicle
- Consists of hard keratinized epithelial cells
- Melanocytes provide pigment for hair color
Hair Anatomy
- Central Medulla
- Cortex surrounds medulla
- Cuticle outside of cortex
- Mostly heavily keratinized
Associated Hair Structures
- Hair follicle
- Dermal and epidermal sheath surround hair root
- Arrector pili muscle
- Smooth muscle
- Pulls hairs upright when cold or frightened (goosebumps)
- Sebaceous gland
- Sweat gland
Nails
- Scale-like modifications of the epidermis
- Heavy keratinized- Stratum basale extends beneath the nail bed
- Responsible for growth
- Lack of pigment makes them colorless
- Cyanotic or Cyantosis - Blue
- Stratum basale extends beneath the nail bed
Nail Structure
- Free edge
- Body is the visible attached portion
- Root of nail embedded in skin
- Cuticle is the proximal nail fold that project onto the nail
Types of Skin Appendages
- Sebaceous Gland
- Sweat Gland
- Hair
- Nails
Composition of Sweat
- Mostly water
- Salts and vitamin C
- Some metabolic waste (Urea, Lactic Acid, Creatine- yellowish)
- Fatty acids and proteins (apocrine only)
Functions of Sweat
- Help dissipate excess heat
- Excretes waste products
- Acidic nature inhibits bacteria growth
- Odor is from associated bacteria
Skin Homeostasis Imbalances (Infections)
- Athlete’s foot (tinea pedis)
- Caused by fungal infection- Boils and carbuncles
- Caused by bacterial infection
- Cold sores
- Caused by virus
- Herpes
- Contact Dermatitis:
- Exposures cause allergic reactions
- Impetigo
- Caused by a bacterial infection (staphylococcus)
- Psoriasis
- Cause is unknown
- Triggered by trauma, infection, stress
- Burns
- Tissue damage and cell death caused by heat, electricity, UV Radiation, or chemicals
- Associated dangers
- Dehydration
- Electrolyte imbalance
- Circulatory shock
- Boils and carbuncles
Rule of Nines
- Way to determine the extent of burns
- Body is divided into 11 areas for quick estimation
- Each area represents about 9% of the total body surface area
First Degree Burns
- Only epidermis is damaged
- Skin is red or swollen
- Partial Burn
Second-degree burns
- Epidermis and upper dermis are damaged
- Skin is red w/ blisters
- Partial Burns
Third-Degree Burns
- Destroys entire skin layer
- Burn is gray-white or black
When are burns considered Critical?
- Over 25% of body has second degree burns
- Over 10% of the body has 3rd degree burns
- There are third-degree burns of the face, hands, or feet
Skin Cancer
- Cancer= abnormal cell mass
- Classified two ways
- Benign:
- Does not spread (encapsulated)
- Malignant:
- Metastasized (Moves) to other parts of the body
- Skin cancer is the most common type of skin cancer
- Benign:
Basal Cell Carcinoma (Type of skin cancer)
- Least malignant
- Most common type
- Arises from stratum basale
Squamous Cell Carcinoma (Types of Cancer)
- Metastasizes to lymph nodes if not removed
- Early removal allows a good chance of cure
- Believed to be sun-induced
- Arises from stratum spinosum
ABCDE
- a= Assymetrical
- Two sides of pigmented mole do not match
- B: Border irregularity
- Borders of mole are not smooth
- C: Color
- Changes color gets dark
- D= Diameter
- Larger than 6 millimeters
- E: Elevation
Merkel Discs
-Sensory Receptors that react to touch
Dessication
-Add keratin to skin, dries it up :)
Functions of the Epidermis
- Protection
- Sensation
- Secretion
- Execution
- Synthesis
- Temperature
- Storage