Bone Tissue, Skeletal System, Joints, and Muscular System Review

Comprehensive vocabulary flashcards covering key structural, cellular, functional, and anatomical concepts of the skeletal system, joints, and muscular system based on lecture slides.

Osseous Tissue

A hard, dense connective tissue that forms most of the adult skeleton.

Hematopoiesis

The production of blood cells, which takes place in the red bone marrow of bones.

Axial Skeleton

The central division of the skeleton consisting of 80 bones, including the skull, vertebral column, rib cage, and hyoid bone.

Appendicular Skeleton

The division of the skeleton consisting of 126 bones, including the extremities (arms and legs), pectoral girdle, and pelvic girdle.

Long Bones

Cylindrical-shaped bones that are longer than they are wide, serving as functional levers in the limbs.

Short Bones

Cube-shaped bones that provide stability and support with limited motion, found exclusively in the wrists (carpals) and ankles (tarsals).

Flat Bones

Thin, slightly curved bones that protect internal organs and provide attachment points for muscles, such as the ribs, sternum, scapulae, and frontal bone.

Irregular Bones

Bones with complex, hard-to-describe shapes, such as the vertebrae, pelvis, and many facial bones.

Sesamoid Bones

Small, rounded bones embedded in tendons or located near joints; the patellae are the largest and the only ones present in every person.

Diaphysis

The tubular shaft of a long bone that extends between the proximal and distal ends.

Medullary Cavity

The hollow canal running through the center of the diaphysis that contains yellow bone marrow in adults.

Epiphysis

The expanded end (proximal or distal) of a long bone, consisting of cancellous spongy bone enveloped by a thin outer layer of compact bone.

Epiphyseal Plate

The layer of hyaline cartilage located at the junction of the diaphysis and epiphysis, where growing long bone adds length; commonly called the growth plate.

Endosteum

The internal membrane lining the medullary cavity and the internal spaces of cancellous bone.

Periosteum

The fibrous membrane that covers the outer surface of the diaphysis of a bone.

Osteoclasts

Multinucleated cells derived from monocytes and macrophages that resorb and break down damaged, old, or unneeded bone cells.

Osteoblasts

Bone-forming cells located in the periosteum and endosteum that secrete bone matrix and are incapable of mitosis.

Osteocytes

Mature, calcified osteoblasts located within lacunae that serve as the primary and most common cell type in mature bone.

Osteogenic Cells

Undifferentiated stem cells located deep in the periosteum and bone marrow that are the only bone cells capable of mitosis and differentiate into osteoblasts.

Lacunae

Small spaces or cavities within the bone matrix that contain osteocytes.

Canaliculi

Microscopic channels in the bone matrix that interconnect adjacent lacunae, allowing osteocytes to communicate and exchange nutrients.

Compact Bone

Dense, hard bone tissue positioned along the outer surfaces of bones to provide structural strength.

Spongy Bone

Porous bone tissue (cancellous bone) containing open spaces filled with red bone marrow.

Intramembranous Bones

Bones that develop directly from sheets of undifferentiated connective tissue without a cartilage model, including the skull, facial bones, and clavicles.

Endochondral Bones

Bones that develop using a cartilage framework that is gradually replaced by bone tissue, such as long bones.

Fracture Hematoma

A localized collection of blood formed 6 to 8 hours after a fracture due to ruptured blood vessels.

Fontanels

Tough membranes connecting incompletely developed cranial bones in infants that allow flexibility during birth.

Foramen Magnum

The large opening at the base of the occipital bone through which the spinal cord passes.

External Auditory Meatus

The canal in the temporal bone commonly known as the ear canal.

Paranasal Sinuses

Mucosa-lined, air-filled cavities within skull bones (frontal, maxillary, sphenoid, ethmoid) that lighten the skull and provide vocal resonance.

Hyoid Bone

A U-shaped bone in the upper neck that does not articulate directly with any other bone, anchoring the tongue and attaching swallowing muscles.

Scoliosis

An abnormal lateral bending or curvature of the vertebral column.

Kyphosis

An excessive posterior curvature of the thoracic vertebral column, commonly caused by osteoporotic compression fractures.

Lordosis

An excessive anterior curvature of the lumbar vertebral column.

Atlas (C1)

The first cervical vertebra, which lacks a body and spinous process and supports the skull.

Axis (C2)

The second cervical vertebra, featuring an upward protrusion called the dens that allows side-to-side rotation of the head.

Anulus Fibrosus

The tough, fibrous outer ring of an intervertebral disc.

Nucleus Pulposus

The gel-like central core of an intervertebral disc that cushions and absorbs shock between vertebrae.

True Ribs

The first 7 pairs of ribs that attach directly to the sternum by costal cartilage.

False Ribs

Rib pairs 8, 9, and 10, which attach indirectly to the sternum via the costal cartilage of rib pair 7.

Floating Ribs

Rib pairs 11 and 12, which have no anterior attachment to the sternum.

Synarthrosis

An immovable joint where articulating bones show no functional movement, such as sutures in the skull.

Amphiarthrosis

A slightly movable joint connected by cartilage, such as intervertebral discs or the pubic symphysis.

Diarthrosis

A freely movable joint characterized by a joint cavity containing synovial fluid.

Epimysium

An outer sheath of dense irregular connective tissue surrounding an entire skeletal muscle.

Perimysium

The middle connective tissue layer that bundles muscle fibers into fascicles.

Endomysium

A delicate connective tissue layer containing collagen that wraps individual muscle fibers within a fascicle.

Sarcolemma

The plasma membrane of a muscle cell or myocyte.

Sarcomere

The functional contracting unit of a skeletal muscle fiber composed of organized thin and thick myofilaments.

Acetylcholine (ACh)

The neurotransmitter released by motor neurons that triggers muscle fiber depolarization and contraction.

Acetylcholinesterase

The enzyme that degrades acetylcholine in the synaptic cleft to allow muscle relaxation.

Creatine Phosphate

An energy compound stored in muscle cells that rapidly regenerates ATP during the initial 15 seconds of contraction.

Oxygen Debt

The amount of additional oxygen required after intense physical exertion to metabolize accumulated lactic acid back into glucose in the liver and restore ATP levels.

Isotonic Contraction

A muscle contraction where muscle length changes while tension remains constant to move a load.

Isometric Contraction

A muscle contraction where muscle length stays the same because the load exceeds the force generated by the muscle.

Intercalated Discs

Specialized cell junctions connecting cardiac muscle cells that allow direct impulse conduction for synchronized pumping.

Automaticity

The intrinsic ability of cardiac pacemaker cells to generate electrical impulses independently without nervous input.

Satellite Cells

Stem-like cells in skeletal muscle tissue that regenerate and repair damaged muscle fibers.

Prime Mover (Agonist)

The primary muscle directly responsible for executing a specific movement.

Synergist

A muscle that assists the prime mover by contributing extra force or stabilizing nearby joints.

Antagonist

A muscle that produces an action opposing that of the prime mover and must relax to facilitate fluid motion.