Muscular System Vocab

Fascia

sheet of dense connective tissue that encloses a muscle

Aponeuroses

sheet of connective tissue that attaches muscle to muscle

Myofibrils

contractile fiber in muscle cells

Myosin

protein that with actin forms the filaments that interact to contract muscle fibers

Sarcomeres

structural and functional unit of a myofibril

Sacroplasmic reticulum

membranous network of channels and tubules of a muscle fiber corresponding to the endoplasmic reticulum of other cells

Transverse tubules

membranous channel that extends inward form a muscle fiber membrane

Motor neurons

neuron that transmits impulses from the central nervous system to an effector

Synapse

functional connection between the axon of a neuron and the dendrite or cell body of another neuron or the membrane of another cell type

Neurotransmitters

chemical that an axon secretes that stimulates or inhibits an effector or other neuron

Neuro-muscular junction

synapse between a motor neuron and a skeletal muscle fiber

Motor end plate

specialized part of a muscle fiber membrane that a neuron muscle junction

Actin

protein in a muscle fiber that forms filaments that slide between filaments of protein myosin contracting muscle fibers

Synaptic cleft

space between two cells forming a synapse

Troponin/Tropomyosin

proteins on the actin filament that are binding sites for the myosin filament

Sliding filament model

the model that is used to explain the sliding of the proteins actin and myosin past each other in skeletal muscle contraction

ATPase

Enzyme that releases energy stored in the terminal phosphate bonds of ATP molecules

Acetylcholinesterase

enzyme that catalyzes break down of acetycholine

Creatine phosphate

muscle biochemical that stores energy

Hemoglobin

oxygen carrying pigment and red blood cells

Myoglobin

pigmented compound and muscle tissue that stores oxygen

Oxygen debt

amount of oxygen required following physical exercise to react accumulated lactic acid to form glucose

Threshold stimulus

a certain strength of stimulation which when reacted generates a electric impulse that spreads throughout the muscle fiber

Twitch

single contraction of a muscle fiber followed by relaxation

Latent period

time between application of a stimulus and the beginning of a response of a muscle fiber

Summation

increased force of a contraction by a skeletal muscle fiber when a twitch occurs before the previous twitch relaxes

Muscle tone

sustained contraction of muscle fibers which originates repeatedly from the spinal cord and stimulates only a few muscle fibers at a time

Peristalsis

rhythmic waves of a muscular contraction of the walls of certain tubular organs

Origin

end of a muscle that attaches to a relatively immovable part

Insertion

end of muscle attached to a movable part

Synergists

muscle that assists the action of an agonist, muscle that helps prime mover in a movement

Summation

increased force of contraction by a skeletal muscle fiber when a twitch occurs before the previous twitch relaxes

Antagonists

muscle that opposes or reverses prime mover