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30 terms

Muscoskeletal System

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Exoskeleton
Protects organism form the outside, includes clams and snails, calcium containing shells.
Endoskeleton
Internal support structure includes bones, cartilage, and plates.
Hydrostatic skeleton
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.
Osteoblasts
Bone forming cells that secrete matrix.
Osteoclasts
Cells that degrade matrix at bone surface, release calcium and phosphorus into blood.
Osteocyte
A former osteoblast embedded in the matrix it produced.
Osteons
Set of concentric rings of osteocytes, contains circulatory vessels and nerves.
Spongy bone
Hard bone with many large spaces, red bone marrow fills the spaces.
Compact bone
Bones that consist of closely packed osteons.
Cartilage
More flexible than bone, lacks blood supply, slow to heal, high water content.
Chondrocytes
Cells in cartilage that secrete collagen and elastin.
Axial skeleton
Consists of skull, vertebral column, and rib cage.
Appendicular Skeleton
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.
Synovial joint
Consists of moveable bones joined by a fluid-filled capsule of fibrous connective tissue.
Sarcomere
One of many repeated units of a myofibril.
Myofibril
Runs the length of a muscle cell, contractile bundle that consists of thin and thick filaments.
Myosin
Thick filament of the myofibril.
Actin
Thin filament of the myofibril.
Muscle fiber
Made up of many myofibrils.
Muscles
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.
Neuromuscular junction
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.
Less myoglobin
Causes whitish appearance of muscles.
More myoglobin
Causes darker appearance of muscles.