Protects organism form the outside, includes clams and snails, calcium containing shells.
Internal support structure includes bones, cartilage, and plates.
Simplest type of skeleton, fluid constrained by flexible tissue, includes jellyfish and worms.
Functions of bones
Support and protection, supply of calcium and other minerals, aid in movement, blood cell formation.
Bone forming cells that secrete matrix.
Cells that degrade matrix at bone surface, release calcium and phosphorus into blood.
A former osteoblast embedded in the matrix it produced.
Set of concentric rings of osteocytes, contains circulatory vessels and nerves.
Hard bone with many large spaces, red bone marrow fills the spaces.
Bones that consist of closely packed osteons.
More flexible than bone, lacks blood supply, slow to heal, high water content.
Cells in cartilage that secrete collagen and elastin.
Consists of skull, vertebral column, and rib cage.
Appendages (limbs) and bones that support them, pectoral and pelvic girdles.
Yellow bone marrow
In the center of longbones, replenishes red bone marrow.
Red bone marrow
Located at the ends of longbones and flatbones. Blood cell formation.
Consists of moveable bones joined by a fluid-filled capsule of fibrous connective tissue.
One of many repeated units of a myofibril.
Runs the length of a muscle cell, contractile bundle that consists of thin and thick filaments.
Thick filament of the myofibril.
Thin filament of the myofibril.
Made up of many myofibrils.
Consists of many bundles of muscle fiber.
Sliding filament model
A muscle fiber contracts when thin filaments slide within thick filaments. The sarcomere shortens. Heads of myosin interact with actin forming a cross-bridge.
Synapse between a motor neuron and a muscle cell.
Muscle movement process
Motor neuron conveys message to muscle cell to contract. Motor neurons release neurotransmitters. Receptors on muscle bind to neurotransmitter. Neurotransmitters to endoplasmic reticulum to release calcium (Ca2+). Calcium binds to protein on actin and allows interaction with myosin. Sarcomeres shorten.
Slow twitch fibers
Small cells. Long duration contractions. Capillaries have good supply of oxygen. Many mitochondria. For endurance.
Fast twitch fibers
Larger cells. Short duration contractions. Powerful contractions. Short term use for strength.