Muscle Anatomy
This characteristic allows a muscle to return to its original length after being stretched
Elasticity
This neurotransmitter is released from the motor neuron to excite skeletal muscle fibers.
Acetylcholine (ACh)
This metabolic pathway occurs in the cytosol and yields a net production of 2 ATP per glucose molecule.
Glycolysis
These fibers, also known as Type I, are the smallest in diameter and are used for endurance activities like marathon running.
Type I
Slow Oxidative (SO) fibers
This is the term for a single, brief contraction and relaxation period in response to one stimulus.
Muscle Twitch
These are the functional units of skeletal muscle, composed of repeating structures of myofilaments
Sarcomeres
These protein molecules make up thick filaments and feature "heads" that bind to thin filaments.
Myosin
This is the gap or space between a motor neuron and a muscle fiber.
Synaptic cleft
These large-diameter fibers provide short-duration, intense movement like lifting weights or sprinting.
Type IIb
Fast Glycolytic (FG) fibers
What causes a Muscle to shorten?
Myosin head attaching to Actin and pull everything towards the middle
Muscles produce this as a byproduct of using energy, helping to maintain body temperature.
Heat
These are the "thin" filaments found in a sarcomere.
Actin
This is the plasma membrane of a muscle cell.
Sarcolemma
These "intermediate" fibers are best suited for medium-duration activities like walking or biking.
Type IIa
(Fast Oxidative (FO) fibers)
These special junctions join cardiac muscle cells together so they can contract as one unit.
Intercalated Discs
This "stringlike" protein covers the myosin binding sites on thin filaments when the muscle is at rest.
Tropomyosin
This ion must bind to troponin to move tropomyosin and allow contraction to occur.
Calcium (Ca2+)
This is the term for a decrease in muscle tension due to repetitive stimulation.
Fatigue
If a muscle is not used, it may get smaller, a process known as ____.
Atrophy
Unlike skeletal muscle, smooth muscle is ____, meaning you cannot consciously control it.
Involuntary
These are circular muscle bands that contract and relax to regulate the passage of material (like in the digestive tract).
Sphincters
This microscopic "stripe" pattern is visible in skeletal and cardiac muscle because of the arrangement of filaments.
Striations
This specialized organelle inside the muscle cell stores and releases Calcium.
Sarcoplasmic Reticulum
This characteristic describes a muscle's ability to respond to a stimulus, like a signal from a nerve.
Excitability
These are the deep indentations of the sarcolemma that allow the electrical signal to reach the inside of the cell quickly.
T-Tubules