Anatomy of Long Bones and Muscle Tissue

Long Bone

Has distinct areas: diaphysis, metaphysis, epiphysis.

Spongy Bone

Porous bone found at ends and tops.

Compact Bone

Solid bone structure, lines the outer surface.

Trabeculae

Structural units of spongy bone, hole-like appearance.

Diaphysis

Long shaft of bone containing medullary cavity.

Metaphysis

Transition area between diaphysis and epiphysis.

Epiphysis

Widened ends of long bones.

Physis

Growth plate, also known as epiphyseal plate.

Endosteum

Membrane lining the medullary cavity.

Periosteum

Outer membrane covering the bone.

Bone Composition

Contains water, minerals, and organic matter.

Wet Weight Ratio

Bone: 25% water, 45% minerals, 30% organic.

Dry Weight Ratio

Bone: 0% water, 70% minerals, 30% organic.

Calcium in Bone

Ca2+ constitutes 37% of bone minerals.

Phosphorus in Bone

P constitutes 18.5% of bone minerals.

Osteoprogenitor Cells

Stem cells that differentiate into bone cells.

Osteoblasts

Cells responsible for building bone matrix.

Osteocytes

Mature bone cells maintaining tissue and communication.

Osteoclasts

Cells that resorb and break down bone.

Haversian System

Canal system in compact bone for blood vessels.

Haversian Canals

Horizontal canals containing blood vessels.

Volkmann Canals

Vertical canals connecting Haversian systems.

Canaliculi

Small channels for osteocyte communication.

Ossification

Process of bone formation, includes endochondral and intramembranous.

Synovial Joints

Freely movable joints with synovial fluid.

Joint Capsule

Two-layered structure enclosing synovial joints.

Ligaments

Connective tissue stabilizing joints.

Skeletal Muscle

Contractible tissue responsible for voluntary movement.

Cardiac Muscle

Involuntary muscle with branched cells and intercalated discs.

Smooth Muscle

Involuntary muscle, non-striated, found in organs.

Muscle Origin

End attached to stationary bone.

Muscle Insertion

End attached to movable bone.

Flexor Muscle

Brings bones closer together.

Extensor Muscle

Moves bones away from each other.

Antagonistic Muscle Groups

Pairs of muscles opposing each other's actions.

Muscle Architecture

Classified as parallel or pennate arrangements.

Epimysium

Outer layer of connective tissue around muscles.

Perimysium

Connective tissue surrounding muscle fiber bundles.

Endomysium

Connective tissue between individual muscle fibers.

Myofibril

Intracellular bundles of contractile proteins.

Sarcoplasmic Reticulum

Releases Ca2+ for muscle contraction.

T-tubules

Transmits electrical signals into muscle fibers.

Actin

Thin filament protein involved in muscle contraction.

Myosin

Thick filament protein forming muscle contractions.

Tropomyosin

Regulatory protein that blocks actin binding sites.

Troponin

Regulatory protein that binds calcium to initiate contraction.

Titin

Giant accessory protein providing structural support.

Nebulin

Accessory protein stabilizing actin filaments.