Integumentary System Flashcards
Define hypodermis:
Subcutaneous tissue layer
Also known as ‘superficial fascia’
What is the integumentary system?
Skin
What are keratinocytes?
Fibrous protein cells which produce keratin
What are melanocytes?
Spider-shaped epithelial cells that synthesize the pigment melanin
Found in deepest layer of epidermis
What are dendritic cells?
Star-shaped arise from bone marrow.
Also called Langerhans cells
Ingest foreign substances
Key in immune system
What are tactile cells?
Also called Merkel cells
Present in epidermal-dermal junction
Associated with a disclike sensory nerve ending
What are the layers of epidermis? (Superficial to deep)
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale
What is the stratum basale?
Deepest epidermal layer
Attached to underlying dermis
Consists of singer row of stem cells
What is stratum spinosum?
Several cell layers thick
Cells contain weblike system of intermediate filaments
“Prickle cells”
What is stratum granulosum?
Thin- consists of 4-6 cell layers
Keratinization occurs here
Creates keratohyaline granules and lamellar granules
What are lamellar granules?
Formed by keratinization within the stratum granulosum.
Contain water-resistant glycolipid –> excreted into extracellular space
Major factor in slowing water loss across epidermis
What is stratum lucidum?
Translucent
Visible only in thick skin
Thin translucent band, just above stratum granulosum
What is stratum corneum?
Durable, Outter-most layer of epidermis
Abundant keratin and thickened plasma membranes protects abrasions and penetrations
Glycolipids between cells protects layer
What is the dermis?
Second major skin region
Strong, flexible connective tissue
Rich supply of nerve fibers, blood vessels and lymphatic vessels
What is the papillary layer?
Thin, superficial layer
Areolar connective tissue
Fine interlacing of collagen and elastic fibers
Abundance of blood vessels
What does ‘papilla’ mean?
Nipple
What is the dermal papillae?
Peglike projections from surface
Indent overlying epidermis
What row friction ridges?
They are assumed to enhance the gripping ability of fingers and feet
What is the reticular layer?
Deepest layer of dermis
80% of thickness of dermis
Coarse, irregularly arranged
Dense fibrous connective tissue
What is a cleavage line?
Externally invisible lines
Tend to run longitudinally in the skin of head bad limbs and in circular patterns around neck and trunk
What are flexure lines ?
Dermal folds occur at or near joints where the dermis is tightly secured to deeper structures
Ex. Palms
What is the function of melanin?
Aids in darkening skin color in order to protect DNA synthesis from UV radiation
What is carotene?
Yellow to orange pigment found in certain plant products
Tends to accumulate in hypodermis
What is the purpose of arrector pili muscle?
Muscle which helps hair stand on end when muscle contracts
