Anatomy Exam 2 Review: Skeletal and Muscular Systems

Comprehensive vocabulary flashcards covering anatomical terminology, osteology, arthrology, and myology from Unit 2.

Perichondrium

The layer of dense connective tissue that surrounds skeletal cartilage.

Interstitial growth

Cartilage growth that occurs when chondrocytes within lacunae divide and secrete new matrix, expanding the tissue from within.

Appendicular skeleton

The skeletal division consisting of the bones of the upper and lower limbs and the girdles (pectoral and pelvic) that attach them to the trunk.

Axial skeleton

The skeletal division forming the central longitudinal axis of the body, including the skull, vertebral column, and ribcage.

Sesamoid bones

Special types of short bones that develop and form within tendons, such as the patella.

Periosteum

The outer wrapping composed of dense irregular connective tissue that covers and protects compact bone.

Medullary cavity

The central internal cavity of a long bone where yellow bone marrow (fat) is stored.

Hematopoiesis

The biological process of blood cell formation occurring within red bone marrow.

Osteoblasts

Actively dividing bone-forming cells that secrete and deposit bone matrix.

Osteoclasts

Specialized bone cells responsible for the breakdown and resorption of bone matrix.

Osteocytes

Mature bone cells situated within lacunae that communicate with neighboring cells via canaliculi.

Osteon

The structural and functional microscopic unit of compact bone.

Canaliculi

Thin, hairlike canals that connect lacunae to each other and to the central canal of an osteon.

Trabeculae

The lattice-like structural arches and struts of spongy bone aligned along lines of mechanical stress to provide strength.

Endochondral ossification

Bone development and growth that proceeds by replacing a preexisting hyaline cartilage model, forming most bones inferior to the occipital bone.

Intramembranous ossification

Bone development process that forms most of the flat bones of the skull directly from fibrous connective tissue membranes.

Osteoporosis

A skeletal condition characterized by reduced bone density that occurs when bone resorption exceeds bone deposition.

Vertebra prominens

The seventh cervical vertebra ($C7$), distinguished as the first vertebra that is readily palpated on the posterior lower neck.

Xiphoid process

The small inferior landmark of the sternum that must be avoided during hand placement in CPR to prevent puncturing underlying organs.

Glenoid cavity

The shallow socket on the lateral aspect of the scapula that articulates with the head of the humerus.

Acetabulum

The deep lateral socket of the os coxa that articulates with the head of the femur.

Syndesmosis

A fibrous joint in which the articulating bones are held together by a ligament or interosseous membrane (e.g., between the radius and ulna).

Gomphosis

A peg-in-socket fibrous joint that anchors teeth into their alveolar sockets.

Synchondroses

A cartilaginous joint wherein the connecting material between bones is specifically hyaline cartilage.

Synovial fluid

A viscous, slippery fluid inside synovial cavities that lubricates articular surfaces and nourishes cartilage.

Bursae

Fluid-filled fibrous sacs lined with synovial membrane that reduce friction between adjacent bones, tendons, ligaments, and skin.

Opposition

The saddle joint motion enabled by the first carpometacarpal joint allowing the thumb to touch the fingertips.

Anterior cruciate ligament (ACL)

A key intracapsular knee ligament that is especially susceptible to injury from lateral impact forces.

Elasticity

The property of muscle tissue that describes its ability to recoil and return to its resting length after being stretched.

Excitability

The ability of muscle cells to receive and respond to electrical or chemical stimuli.

Perimysium

A sheath of dense irregular connective tissue wrapping around and bundling individual muscle fibers into fascicles.

Origin

The attachment point of a muscle to an immovable or less movable bone, typically positioned proximally on limbs or medially on the trunk.

Insertion

The attachment point of a muscle to a movable bone, typically positioned distally on limbs or laterally on the trunk.

Myofibrils

Densely packed rod-like contractile organelles found in muscle fibers that occupy approximately $80\%$ of cell volume.

Neuromuscular junction

The specific synaptic site where a motor neuron terminal interacts with the motor end plate of a muscle fiber.

Antagonist

A muscle that opposes or reverses a particular action produced by a prime mover.

Bipennate muscle

A fascicle arrangement in which muscle fibers insert diagonally into both sides of a central tendon, as seen in the rectus femoris.

Extensor digiti minimi

A forearm muscle whose primary functional action is extending the fifth digit (pinky finger).

Comminuted fracture

A type of bone fracture in which the bone breaks or is crushed into three or more pieces.

Disuse atrophy

The degeneration and loss of muscle mass caused by immobilization or lack of use, which can result in muscle tissue replacement by dense irregular connective tissue.