Locomotion: Skeletons, Muscles and Movement

These flashcards cover vocabulary related to locomotion, skeletons, and muscles, focusing on their structures and functions.

Hydrostatic Skeletons

Fluid-filled cavities under pressure, providing support and aiding in movement, but lacking protection.

Exoskeleton

A hard outer structure made of chitin and protein that provides support, often found in arthropods.

Endoskeleton

A hard support structure embedded in soft tissue, typical in chordates, made of cartilage or bone.

Osteoblasts

Living cells that form new bone.

Osteoclasts

Cells that dissolve bone tissue to alter its structure.

Skeletal Muscle

Striated muscle involved in locomotion, made up of muscle fibers that are multinucleate.

Sarcomere

The functional unit of a muscle, composed of thick and thin filaments that slide past each other during contraction.

Myofibrils

Bundles within muscle fibers made of myofilaments, responsible for muscle contraction.

Isotonic Contraction

Muscle contraction where tension remains the same but the muscle shortens to move a load.

Isometric Contraction

Muscle contraction where length remains constant, but tension increases against a heavy load.

Cross-Bridge Attachment

The temporary binding of myosin to actin during muscle contraction.

Troponin

A regulatory protein that, when bound by calcium, allows contraction by exposing myosin binding sites on actin.

Tropomyosin

A regulatory protein that blocks myosin binding sites on actin in a relaxed muscle.

Graded Contractions

Varying levels of muscle contractions resulting from the firing of different numbers of motor units.

Motor Unit

A motor neuron and all the muscle fibers it innervates, allowing the nervous system to control muscle contraction strength.

Tetanus

Sustained muscle contraction resulting from rapid succession of stimuli, leading to maximum force.