BIOL 209 Unit 2 Review - Skeletal System, Joints, and Muscular System

Vocabulary flashcards covering key terms and concepts for BIOL 209 Unit 2 Exam on the Skeletal System, Joints, and Muscular System.

Hemopoiesis

The process of producing red blood cells, white blood cells, and platelets within red bone marrow.

Diaphysis

The shaft or long main cylindrical body of a long bone.

Epiphysis

The proximal and distal extremities or ends of a long bone.

Metaphysis

The region in a mature bone where the diaphysis joins the epiphysis, containing the epiphyseal plate during growth.

Periosteum

A tough sheath of dense irregular connective tissue surrounding the bone surface wherever it is not covered by articular cartilage.

Medullary cavity

The hollow, cylindrical space within the diaphysis that contains yellow bone marrow in adults.

Endosteum

A thin membrane lining the medullary cavity containing a single layer of bone-forming cells.

Epiphyseal plate

A layer of hyaline cartilage located in the metaphysis of a growing bone that allows the diaphysis to grow in length.

Yellow bone marrow

Bone marrow consisting mainly of adipose cells that store triglycerides as a chemical energy reserve.

Red bone marrow

A highly vascularized connective tissue located in certain bones that produces blood cells through hemopoiesis.

Calcification

The process by which mineral salts are deposited into a collagen matrix and crystallized, causing bone tissue to harden.

Osteoprogenitor cells

Unspecialized stem cells derived from mesenchyme that undergo cell division to form osteoblasts.

Osteoblasts

Bone-building cells that synthesize and secrete collagen fibers and organic components to build extracellular matrix.

Osteocytes

Mature bone cells derived from osteoblasts that maintain daily bone tissue metabolism and matrix exchange.

Osteoclasts

Large multinucleated cells derived from monocytes that break down and resorb bone extracellular matrix.

Osteon

The fundamental structural and functional unit of compact bone tissue, consisting of concentric lamellae arranged around a central canal.

Lamellae

Concentric rings of hard, calcified extracellular matrix surrounding central canals in compact bone.

Lacunae

Small spaces located between concentric lamellae that contain osteocytes.

Canaliculi

Tiny channels radiating from lacunae containing extracellular fluid and osteocyte processes that connect lacunae to each other and central canals.

Osteonic canal

A central longitudinal canal in an osteon containing blood vessels, lymphatic vessels, and nerves.

Compact bone

Dense bone tissue with few spaces that forms the strong outer layer of all bones and provides support and resistance to stress.

Spongy bone

Bone tissue consisting of trabeculae lacking true osteons, located inside bones to protect marrow and reduce overall weight.

Trabeculae

An irregular lacy network of thin columns of bone tissue characteristic of spongy bone.

Bone remodeling

The continuous ongoing replacement of old bone tissue by new bone tissue through bone resorption and deposition.

Osteoporosis

A condition characterized by a decrease in bone mass and density, causing fragile bones susceptible to fracture.

Intramembranous bone formation

The process of bone development directly within sheet-like mesenchyme membranes without a prior cartilage stage.

Endochondral bone formation

The process of bone development where hyaline cartilage model is gradually replaced by bone tissue.

Interstitial bone growth

Lengthwise growth of bones occurring at the epiphyseal plate during childhood and adolescence.

Appositional bone growth

Growth in width or outer circumference of bone caused by deposition of matrix on the bone surface.

Synarthrosis

An immovable joint functionally classified to provide high stability.

Amphiarthrosis

A slightly movable joint functionally classified to allow limited movement.

Diarthrosis

A freely movable joint, all of which are structurally classified as synovial joints.

Fibrous joint

A structural class of joint where articulating bones are held together by dense irregular connective tissue without a synovial cavity.

Cartilaginous joint

A structural class of joint where articulating bones are joined by cartilage without a synovial cavity.

Synovial joint

A structural class of joint characterized by the presence of a synovial cavity between articulating bones.

Articular capsule

A two-layered sleeve surrounding a synovial joint, consisting of an outer fibrous membrane and inner synovial membrane.

Synovial fluid

A viscous, slippery fluid secreted by the synovial membrane that reduces friction, absorbs shock, and provides nutrients to articular cartilage.

Meniscus

A pad of fibrocartilage situated between opposing bone surfaces within a synovial joint that improves joint fit and shock absorption.

Bursa

A sac-like fluid-filled structure positioned to reduce friction between skin, muscle, tendons, or bones around joints.

Electrical excitability

The ability of muscle fibers and neurons to respond to stimuli by producing electrical signals called action potentials.

Contractility

The ability of muscle tissue to contract forcefully when stimulated by an action potential.

Extensibility

The ability of muscle tissue to stretch within limits without sustaining structural damage.

Elasticity

The ability of muscle tissue to return to its original length and shape after extension or contraction.

Sarcolemma

The plasma membrane enclosing a skeletal muscle fiber cell.

Sarcoplasm

The cytoplasm of a muscle fiber containing glycogen and myoglobin.

Sarcoplasmic reticulum

A fluid-filled system of membranous sacs encircling each myofibril that stores and releases calcium ions for contraction.

Myoglobin

A red-colored oxygen-binding protein found in the sarcoplasm of muscle fibers.

Myofibril

A cylindrical contractile organelle inside a muscle fiber extending along its entire length, containing thick and thin myofilaments.

Sarcomere

The basic functional contractile unit of a myofibril bounded by adjacent Z-discs.

Neuromuscular junction

The synaptic site where a somatic motor neuron axon terminal meets a skeletal muscle fiber.

Acetylcholine (ACh)

The neurotransmitter released from synaptic vesicles at the neuromuscular junction to trigger a muscle action potential.

Transverse tubules (T-tubules)

Tiny invaginations of the sarcolemma that tunnel toward the center of the muscle fiber to rapidly transmit action potentials.

Motor unit

A single somatic motor neuron along with all the individual skeletal muscle fibers it innervates.

Slow oxidative fibers

Muscle fibers rich in myoglobin and mitochondria that rely on aerobic respiration to resist fatigue for long endurance activities.

Fast glycolytic fibers

Muscle fibers with low myoglobin and few mitochondria that rapidly generate ATP via anaerobic glycolysis for brief powerful contractions.

Intercalated discs

Irregular transverse thickenings of the sarcolemma connecting adjacent cardiac muscle cells, containing desmosomes and gap junctions.

Dense bodies

Structures in smooth muscle fibers that anchor thin filaments, functionally analogous to Z-discs in striated muscle.