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What is the connective tissue covering that encloses the sarcolemma of an individual muscle fiber?

Endomysium

What is a fascicle?

A bundle of muscle fibers enclosed by a connective tissue sheath.

What do thin myofilaments contain?

Actin

What do thick myofilaments contain?

Myosin

What is the function of T tubules in muscle contraction?

To transmit the action potential deep into the muscle cells.

What are the sites where the motor nerve impulse is transmitted to skeletal muscle cell membranes?

Neuromuscular junctions.

What is contraction elicited by a single brief stimulus called?

A twitch.

What is a smooth, sustained contraction resulting from very rapid stimulation with no relaxation called?

Fused tetanus.

What is a characteristic that does NOT apply to isometric contractions?

Shortening.

What provides ATP fastest during muscle contraction?

Coupled reaction of creatine phosphate with ADP.

What type of respiration provides the highest yield of ATP per glucose molecule?

Aerobic respiration of glucose.

What neurotransmitter is released by somatic motor neurons?

Acetylcholine.

Which ions enter the skeletal muscle cell during action potential generation?

Sodium ions.

What is the function of myoglobin in the muscle?

Holds a reserve supply of oxygen.

What effect does aerobic exercise NOT have?

Increased size and strength of existing muscle cells.

What type of smooth muscle is found in the walls of digestive and urinary system organs?

Unitary smooth muscle.

What is excitability in muscle functional abilities?

The ability to receive and respond to stimuli.

What does indirect attachment of muscle involve?

Connective tissue extends as a tendon or aponeurosis.

What is the importance of acetylcholinesterase?

It breaks down acetylcholine to prevent continuous muscle contraction.

What does excitation-contraction coupling refer to?

The process where an action potential leads to muscle contraction.

What constitutes a motor unit?

A motor neuron and all the muscle fibers it controls.

What defines muscle fatigue?

The inability of muscle to contract despite stimulation.

What causes rigor mortis?

ATP depletion prevents myosin heads from detaching from actin.

What is the structure of a sarcomere?

Contains actin and myosin filaments between Z discs.

What happens during the sliding filament model of muscle contraction?

Myosin heads pull actin filaments, shortening the sarcomere.

What characterizes smooth contractions compared to vigorous contractions?

Small contractions recruit fewer motor units.

What is a property of smooth muscle?

Uses less energy and sustains contractions.

What does Chemical A do in relation to muscle contraction?

Blocks ACh receptors, preventing muscle contraction.