3 The Skeletal System Free Online FlashCards

What gives bone both flexibility and hardness?

Bone matrix combines flexible collagen fibers with mineral crystals, mainly calcium phosphate, which give bone hardness and strength.

Where is compact bone especially thick in a long bone?

Compact bone is dense and forms much of the outer layer of most bones; it is especially thick along a long bone’s shaft.

What are the bony struts in spongy bone called?

Spongy bone is a lattice of bony struts called trabeculae. This structure provides strength while keeping the skeleton relatively light.

How do red marrow and yellow marrow differ?

Red marrow produces red blood cells, white blood cells, and platelets. Yellow marrow, found mainly in adult long-bone cavities, stores fat.

What are the shaft and expanded ends of a long bone called?

The diaphysis is the shaft; the epiphyses are the expanded ends.

What is the periosteum, and what does it provide?

The periosteum is the membrane covering a bone’s outer surface. It contains blood vessels and nerves and provides attachment sites for tendons and ligaments.

What structures make up the axial skeleton?

The axial skeleton has 80 bones and includes the skull, auditory bones, hyoid, vertebral column, ribs, and sternum. It forms the central axis and helps protect the brain, spinal cord, and chest organs.

What does the appendicular skeleton include?

The appendicular skeleton has 126 bones: the upper and lower limbs and the girdles that attach them to the axial skeleton.

How are joints classified structurally?

Fibrous joints connect bones with fibrous connective tissue; cartilaginous joints connect them with cartilage; synovial joints meet within a fluid-filled cavity.

What do the functional joint classes describe?

Synarthroses are essentially immovable, amphiarthroses are slightly movable, and diarthroses are freely movable. All synovial joints are diarthroses.

What structures cushion, enclose, and lubricate a synovial joint?

Articular cartilage cushions the bone ends, a capsule encloses the joint, and synovial fluid lubricates the moving surfaces. Ligaments connect bone to bone and help stabilize the joint.

How do hinge, pivot, and ball-and-socket joints differ?

Hinge joints mainly allow bending and straightening; pivot joints allow rotation; ball-and-socket joints allow movement in several directions.