Anatomy and Physiology Chapters 5, 6, and 8 Vocabulary Review

Vocabulary practice flashcards created from lecture review slides covering the Integumentary System, Skeletal System, and Joint Articulations.

Keratinocytes

The most abundant epidermal cells that produce the fibrous protein keratin, providing structure, durability, and waterproofing to the skin.

Melanocytes

Cells constituting $10\text{-}25\text{\%}$ of the deepest epidermis that synthesize the pigment melanin, which is packaged into melanosomes to protect keratinocyte nuclei from UV damage.

Dendritic cells

Epidermal macrophages (also called Langerhans cells) that serve as key activators of the immune system.

Tactile cells

Sensory touch receptors in the epidermis (also called Merkel cells) that associate with nerve endings in the dermis.

Stratum corneum

The most superficial epidermal layer composed of $20\text{-}30$ layers of dead, flattened membranous sacs filled with keratin and extracellular glycolipids.

Stratum granulosum

An epidermal layer typically containing five layers of flattened cells with deteriorating organelles, filled with lamellar granules and keratohyaline granules.

Stratum spinosum

An epidermal layer composed of several layers of keratinocytes unified by desmosomes, containing thick bundles of intermediate filaments made of pre-keratin.

Stratum basale

The deepest epidermal layer consisting of a single row of actively mitotic stem cells, as well as occasional melanocytes and dendritic cells.

Dermal papillae

Peg-like projections of the dermis containing capillary loops, touch receptors, or pain receptors; in thick skin, they lie atop dermal ridges to produce friction ridges.

Friction ridges

Epidermal ridges created by underlying dermal ridges and papillae that enhance gripping ability, contribute to touch perception, and form fingerprints.

Flexure lines

Dermal folds occurring at or near joints where the dermis is tightly secured to deeper structures, creating deep skin creases because skin cannot slide easily.

Striae

Silvery-white scars, commonly called stretch marks, caused by extreme skin stretching that tears the dermis.

Blister

A fluid-filled pocket separating epidermal and dermal layers caused by acute, short-term trauma such as a burn.

Compact bone

The dense and solid outer layer of bone structure.

Spongy bone

Internal bone tissue (also called diploë in flat bones) consisting of a honeycomb network of small needle-like or flat pieces called trabeculae.

Trabeculae

Supporting bundles or plates of bone fibers that form the meshwork of spongy bone.

Osteocyte

A mature bone cell that monitors and maintains the mineralized bone matrix.

Osteoclast

A multinucleated cell responsible for bone resorption and degradation of the bone matrix.

Osteon

The fundamental structural unit of compact bone, also known as a Haversian system.

Sharpey's fibers

Perforating fibers made of collagen that secure the periosteum to the underlying bone matrix.

Parathyroid hormone

A hormone released by the parathyroid glands when blood Ca2+ levels drop below normal ($9\text{-}11\text{ mg}/100\text{ ml}$), stimulating osteoclasts to degrade bone matrix and restore blood Ca2+ levels.

Wolff's law

The principle stating that bone grows or remodels in response to the mechanical forces or stress placed upon it.

Nondisplaced fracture

A bone fracture where the bone ends retain their normal alignment.

Displaced fracture

A bone fracture where the bone ends are pulled out of normal alignment.

Complete fracture

A bone fracture in which the bone is broken entirely through.

Incomplete fracture

A bone fracture in which the bone is not broken all the way through.

Open fracture

Also called a compound fracture; a bone fracture in which the broken bone penetrates through the skin.

Closed fracture

Also called a simple fracture; a bone fracture in which the skin remains intact.

Sutures

Immovable fibrous joints occurring only between skull bones, formed by wavy interlocking bone edges held together by short connective tissue fibers.

Synostoses

Closed, completely ossified, and fused sutures that turn into solid bony joints in middle age.

Syndesmoses

Fibrous joints in which bones are connected exclusively by ligaments or fibrous tissue bands.

Gomphoses

Peg-in-socket fibrous joints that anchor teeth into alveolar sockets via the periodontal ligament.

Synchondroses

Cartilaginous joints united by a bar or plate of hyaline cartilage, such as epiphyseal plates or costal cartilage.

Symphyses

Amphiarthrotic cartilaginous joints in which fibrocartilage unites the bones, such as intervertebral discs and the pubic symphysis.

Bursae

Flattened fibrous sacs lined with synovial membrane containing synovial fluid that reduce friction where ligaments, muscles, skin, or tendons rub against bone.

Tendon sheaths

Elongated bursae that wrap completely around tendons subjected to friction.

Supination

Movement of the forearm that rotates the radius laterally so the palm faces anteriorly or upward, keeping the radius and ulna parallel.

Pronation

Movement of the forearm that rotates the radius medially across the ulna, turning the palm posteriorly or downward.

Dorsiflexion

Lifting of the foot so that its superior surface approaches the shin.

Plantar flexion

Depressing the foot to point the toes downward.

Inversion

Special movement of the foot that turns the sole medially.

Eversion

Special movement of the foot that turns the sole laterally.

Protraction

Nonangular anterior movement of a body part in a transverse plane, such as jutting out the jaw.

Retraction

Nonangular posterior movement of a body part in a transverse plane, such as pulling back the jaw.

Elevation

Lifting a body part superiorly, such as closing the jaw.

Depression

Moving an elevated body part inferiorly, such as opening the jaw.

Opposition

Special action of touching the thumb to the tips of other fingers on the same hand.

Plane joint

A nonaxial synovial joint with flat articular surfaces that allows simple gliding movements.

Hinge joint

A uniaxial synovial joint in which a cylindrical surface fits into a trough, permitting flexion and extension.

Pivot joint

A uniaxial synovial joint in which a rounded bone end fits into a sleeve or ring composed of bone and ligament, permitting rotation.

Condylar joint

A biaxial synovial joint with oval articular surfaces that allow flexion, extension, abduction, and adduction.

Saddle joint

A biaxial synovial joint in which both articular surfaces have complementary concave and convex areas, as in the carpometacarpal joint of the thumb.

Ball-and-socket joint

A multiaxial synovial joint in which a spherical head fits into a cup-like socket, allowing full freedom of movement in all axes.

Osteoarthritis

A common, irreversible, degenerative 'wear-and-tear' arthritis marked by enzyme-mediated breakdown of articular cartilage.

Rheumatoid Arthritis

A chronic inflammatory autoimmune disorder where the immune system attacks joint tissues, beginning with inflammation of the synovial membrane.

Pannus

An abnormal, inflamed, thickened layer of synovial tissue characteristic of rheumatoid arthritis that clings to and destroys articular cartilage.

Ankylosis

A stiff, fused joint state resulting when scar tissue created by articular cartilage erosion in rheumatoid arthritis ossifies.

Gouty Arthritis

Agonizingly painful joint inflammation triggered when excessive blood levels of uric acid form needle-shaped crystals in joint tissues.