Integumentary System Flashcards
Name the layers of the epidermis from deepest to most superficial.
Stratum basale, stratum spinosum, stratum granulosum, stratum corneum
Where are melanocytes found?
Stratum basale
What is another name for stratum basale?
Stratum germinativum
Which epidermal layer contains thick intermediate filaments that resist tension in the cell and are anchored to desmosomes?
Stratum spinosum
Which layer are dendritic cells most abundant in?
Stratum spinosum
Which epidermal layer consists of 5 cell layers in which keratinocyte appearance changes drastically?
Stratum granulosum
In which epidermal layer does keratinization begin?
Stratum granulosum
What two granules begin to accumulate as keratinization of the epidermal cells begins?
Keratohyaline granules and lamellar granules
What are lamellar granules?
Granules that begin to accumulate in the stratum granulosum and contain a water-resistant glycolipid that is secreted into the extracellular space, slowing water loss.
Which epidermal layer is the uppermost layer that can still receive nutrients?
Stratum granulosum
What molecule makes the stratum corneum nearly waterproof?
Glycolipids between cells
Which layer of the dermis consists of areolar connective tissue and many small blood vessels?
Papillary dermis
What are found in the dermal papillae?
Meissner’s corpuscles, lamellar corpuscles, capillary loops, nerve endings
What are Meissner’s corpuscles?
Touch receptors (of light touch) located in the dermal papillae
Which dermal layer accounts for 80% of the dermis? What kind of tissue is it made of?
The reticular dermis, made of dense irregular connective tissue
What lies between the reticular dermis and the subcutaneous layer? What is its purpose?
The dermal vascular plexus; a network of blood vessels that nourish the reticular dermis
Which epidermal layer is the thickest layer of LIVING cells? How many layers does it usually have?
Stratum spinosum; 8 to 10 layers
What are the dead cells of the stratum corneum called?
Corneocytes or squames
What does the reticular dermis consist of?
Collagen and elastic fibers, adipose cells, hair follicles, nerves, sebaceous glands, and sudoriferous glands
What corpuscles are responsible for sensing deep pressure?
Pacinian
What are the dermal papillae of thick skin responsible for?
Friction ridges (fingerprints)
What are cleavage lines and what is their significance in medicine?
They represent the natural orientation of the underlying collagen fibers; tend to run longitudinally in the skin of the limbs and in circular patterns around the neck and trunk. Surgeons attempt to make incisions parallel to these lines.
What are flexure lines?
Dermal folds that occur at or near joints, such as lines in the palm.
What two sensory receptors are responsible for light touch?
Meissner’s corpuscles and root hair plexuses
What sensory receptors are responsible for heavy touch?
Pacinian corpuscles, merkel cells, Ruffini endings
Which sensory receptor is responsible for sensing skin stretch?
Ruffini endings
Which sensory receptors are responsible for sensing pain, temperature, and itch?
Free nerve endings
What are the functions of hair?
Protection, reduction of heat loss, sensing light touch
What is hair made of?
Keratinized epidermal cells
What are the three concentric layers of keratinized cells found in a hair, from innermost to outermost?
Medulla, cortex, cuticle
What is lanugo?
Fine, non-pigmented downy hairs that cover the body of the fetus
What are vellus hairs?
Short, fine, pale hairs barely visible to the naked eye
What are terminal hairs?
Long, coarse, heavily pigmented hairs
What are the sensory nerve endings that wrap around each hair bulb called?
Hair follicle receptor or root hair plexus
The wall of a hair follicle has a dermal and an epidermal component. What are the three layers called?
The fibrous sheath, glassy membrane, and epithelial root sheath
What is the hair matrix?
Responsible for hair growth, a layer of dividing cells in the bulb of the follicle that lie adjacent to the hair papilla
What is the eponychium?
The nail cuticle
What is the nail matrix?
The thickened, proximal portion of the nail bed, responsible for growth
What is the hyponychium?
The region beneath the free edge of the nail where debris often accumulates; secures the free edge of the nail plate at the tip of the finger/toe
What are the two types of sudoriferous glands?
Eccrine and apocrine
Where are eccrine glands abundant?
Forehead, palms, soles of feet
What is sweat composed of?
99% water, some salts, traces of metabolic wastes such as urea, urinary acid, and ammonia, and dermcidin, an antimicrobial peptide
What is the typical pH of sweat?
4-6
Where are apocrine sweat glands found?
Axillary and anogenital areas
Where are apocrine glands found in the skin layer as compared to eccrine glands?
They are found deeper in the dermis, sometimes extending to the subcutaneous tissue. Their ducts empty into hair follicles.
What do the secretions of apocrine glands contain?
Sweat plus proteins and fatty substances
What are two important modified apocrine glands?
Mammary glands and ceruminous glands
Which epidermal exocrine gland is a holocrine gland?
Sebaceous gland
The action of what muscle forces sebum out of sebaceous glands?
Arrector pili muscle
What are the functions of sebum from sebaceous glands?
Softens and lubricates hair and skin, prevents hair from becoming brittle, slows water loss, bactericidal
Where are sebaceous glands found?
Everywhere except palms and soles
What is the difference between a sebaceous gland and sebaceous follicle?
A sebaceous gland accompanies a hair follicle while a sebaceous follicle stands alone
Where does carotene accumulate in the skin?
Stratum corneum
What is damaged in a first degree burn?
Only the epidermis
What is damaged in a 2nd degree burn?
The epidermis and upper dermis
What is the visible difference between a first and second degree burn?
Blisters appear with a second degree burn
What is damaged in a third degree burn?
The entire thickness of the skin
What would make a 2nd degree burn critical?
If more than 25% of the body is affected
When is a 3rd degree burn critical?
When over 10% of the body is affected
