Integumentary System-skin Flashcards
Cutaneous Membrane
skin
Two Components of the Cutaneous Membrane
- Outer epidermis
- Inner dermis
◦ Hypodermis
the Superficial epithelium (epithelial tissues)
Outer epidermis
-Connective tissues
◦ Hypodermis: Area of loose connective tissue deep to the
dermis (Subcutaneous)
inner dermis
Area of loose connective tissue deep to the
dermis (Subcutaneous)
Hypodermis
where does Accessory Structures
Originate
dermis
Accessory Structures examples
-Hair
-Nails
-Multicellular exocrine glands
(sweat glands, apocrine sweat glands, eccrine sweatglands, sebaceous gland)
cutaneous plexus
artery & vein
Functions of Skin
Protection of underlying tissues and organs
◦ Excretion of salts, water, and organic wastes (glands)
◦ Maintenance of body temperature (insulation and evaporative
cooling)
◦ Production of melanin
◦ Production of keratin
◦ Synthesis of vitamin D3
◦ Storage of lipids
◦ Detection of touch, pressure, pain, and temperature
The most abundant cells;
Contain large amounts of keratin
keratinocytes
Covers most of body; 4 layers; thin stratum corneum
Thin skin
-stratum corneum
-stratum granulosum
-stratum spinosum
-stratum basale
Palms, Soles; 5 layers; thick stratum corneum
Thick skin
-stratum corneum
-STRATUM LUCIDUM IS PRESENT
-stratum granulosum
-stratum spinosum
-stratum basale
AVASCULAR
epidermis
vascular
dermis
-Nutrients and oxygen diffuse from capillaries in the dermis
-Cells on surface (far from dermis) are dead cells
Avascular stratified squamous epithelium
Structures of the Epidermis
The five strata of keratinocytes in thick skin
◦ From basal lamina to free surface (basal surface to apical
surface)
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum (NOT in thin skin!!!!)
- Stratum corneum
-Is attached to basement membrane by hemidesmosomes
-Forms epidermal ridges that extend down towards the dermis
(cause fingerprints)
-Has many basal cells or germinative cells
Stratum Basale
extend down towards the dermis
(cause fingerprints)
epidermal ridges
Dermis forms——that extend up towards the
epidermis
Dermal papillae
Increase the SA of basement membrane and strengthen bond between
dermis and epidermis
ER and DP
Specialized Cells of Stratum Basale
◦ Merkel cells
◦ Melanocytes
◦ Found in hairless skin
◦ Respond to touch (trigger nervous system when compressed)
◦ Merkel cells
◦ Contain the pigment melanin
◦ Responsible for brown pigment of skin
◦ Scattered throughout stratum basale with processes into superficial layers
◦ Melanocytes
◦ 8 to 10 layers of keratinocytes bound by desmosomes
◦ Produced by division of stem cells in stratum basale
◦ Cells continue to divide, increasing thickness of epithelium
◦ Contain dendritic (Langerhans) cells active in immune response
Stratum Spinosum
-cells active in immune response
-Pathogens that pass superficial layers
-Superficial skin cancers
dendritic (Langerhans) cells
◦ 3-5 layers of Keratinocytes derived from stratum
spinosum
◦ Cells stop dividing, start producing
◦ Keratin
◦ Keratohyalin
Stratum Granulosum
◦ A tough, fibrous protein that makes up hair, nails, skin
◦ Makes cells water resistant and resistant to abrasion
keratin
◦ Dense granules that promote dehydration of cells
◦ Promotes aggregation and cross-linking of keratin fibers
Keratohyalin
◦ Found only in thick skin
◦ Flat, densely packed cells filled with keratin
◦Stratum Lucidum
◦ Exposed surface of skin
◦ 15 to 30 layers of keratinized cells
◦ Tightly packed, Water resistant, connected by desmosomes (peels in sheets)
◦ Shed and replaced every 2 weeks
Stratum Corneum
◦ The formation of a layer of dead, protective cells filled with
keratin
◦ Occurs on all exposed skin surfaces except eyes
◦ Skin life cycle from stem cell division to death
◦ It takes 15–30 days for a cell to move from stratum basale to
stratum corneum
Keratinization
Perspiration
2 kinds
◦ Insensible perspiration
◦ Sensible perspiration
◦ Interstitial fluid lost by evaporation through the stratum corneum (500 mL/day)
◦ Damage to epidermis may greatly increase amount (burns, blisters)
◦ Osmosis affects flow thru stratum corneum: in hypotonic fresh water, water flows
into epidermis causing swelling (Prune fingers)
◦ Insensible perspiration
Osmosis affects flow thru stratum corneum: in hypotonic fresh water, water flows
into epidermis causing swelling or———
Prune fingers
◦ Water excreted by sweat glands
◦ Sensible perspiration
is influenced by pigments (Carotene and Melanin) and by blood
circulation
Skin color
- Orange-yellow pigment found in orange vegetables
- Accumulates in epidermal cells and fatty tissues of the dermis
- Can be converted to vitamin A
Carotene
- Yellow-brown or black pigment produced by melanocytes in stratum basal
- Stored in transport vesicles (melanosomes)
- Transferred to keratinocytes
Melanin
Melanin is produced by ??? in stratum basal
melanocytes
transport vesicles
(melanosomes)
Function of Melanocytes
- Produce the melanin that protects skin/ tissues from sun damage
- Ultraviolet (UV) radiation causes DNA mutations and burns that lead to
cancer and wrinkles - Skin darkens with an increase in melanin production, not number of
melanocytes - Albino individuals have normal distribution of melanocytes, they however
donot produce any melanin - In dark skinned people melanocytes release melanosomes more
superficially
is a pigment found in RBC
- Hemoglobin
- When oxygen is bound to hemoglobin it is
bright red
- When hot, superficial blood vessels will??
When hot, superficial blood vessels dilate, skin reddens
Blood flow decreases skin will?
- Blood flow decreases, skin pales
- Caused by severe reduction in blood flow or oxygenation
- Bluish skin tint
- First seen in lips, under nails
Cyanosis
- Epidermal cells produces?
cholecalciferol (vitamin D3)
- Epidermal cells produce cholecalciferol (vitamin D3)
- In the presence of UV radiation
- Liver and kidneys convert vitamin D3 into calcitriol
- Aides in absorption of calcium and phosphorus
- Insufficient vitamin D3
- Can cause rickets
Vitamin D3
Liver and kidneys convert vitamin D3 into
calcitriol
* Aides in absorption of calcium and phosphorus
- Aides in absorption of calcium and phosphorus
calcitriol
- Insufficient vitamin D3
Can cause
rickets
- Located between epidermis and subcutaneous layer (hypodermis)
- Anchors epidermal accessory structures (hair follicles, sweat glands)
The Dermis
- Two components of the dermis
- Outer papillary layer
- Deep reticular layer
- Consists of areolar connective tissue
- Contains small capillaries, lymphatics, and sensory neurons
- Has dermal papillae projecting up between epidermal ridges
The Papillary Layer
- Increases surface area; strengthens bond
dermal papillae
- Responsible for fingerprints
epidermal ridges
- Consists of dense irregular connective tissue
- Contains larger blood vessels, lymphatic vessels, and nerve fibers
- Contains collagen and elastic fiber
The Reticular Layer
form meshwork to strengthen tissues that are stressed from many different angles
fibers
Nerve fibers in skin control:
- Blood flow
- Gland secretions
- Sensory receptors provide information to nervous system
Sensory receptors provide information to nervous system
- Light touch—tactile corpuscles (Meissner’s corpuscles), located in
dermal papillae - Deep pressure and vibration—lamellated corpuscles (Pacinian
corpuscles), in the reticular laye
—tactile corpuscles (Meissner’s corpuscles), located in
dermal papillae
light touch
—lamellated corpuscles (Pacinian
corpuscles), in the reticular layer
Deep pressure and vibration
tactile corpuscles also called & located in
Meissner’s corpuscles located in
dermal papillae
lamellated corpuscles also called & located in
Pacinian
corpuscles, in the reticular layer
lies below the integument
* Made of connective tissue and adipose tissues
* Connected to the reticular layer of integument by connective tissue fibers
* Allows separate movement of skin
* The site of subcutaneous injections using hypodermic needles
- The Hypodermis or Subcutaneous layer
- The Hypodermis (Subcutaneous Layer) is Made of connective tissue and adipose tissues for what functions
- Insulation
- Energy reserve
- Shock absorber and stabilizer
- The site of subcutaneous injections using
hypodermic needles
- Integumentary accessory structures
- Derived from embryonic epidermis
- Located in dermis
- Project through the skin surface
Hair, Hair Follicles, Sebaceous Glands, Sweat
Glands, and Nails
