Myofibrils are made up of ____.

• filaments

• sarcomeres

• sarcoplasm

• sarcolemma

Parallel strands of fibers in muscle fibers that are active in muscle contraction (Letter C) is called _________.

• Sarcolemma

• Sarcoplasm

• Sarcoplasmic reticulum

• Myofibril

The ____________________________ contains specific receptors for the neurotransmitter.

• Synaptic cleft

• Motor end plate

• Neuromuscular junction

• Synaptic vesicle

Neurons communicate with the muscle fiber by way of chemicals called _______.

• Synaptic cleft

• Neurotransmitters

• Neuromuscular junction

• Synapse

Bundles of skeletal muscle fibers, called ________, within each muscle.

• Fascia

• Fascicle

• Epimysium

• Perimysium

The endoplasmic reticulum of a muscle fiber (Letter B) is called ___________.

• Sarcolemma

• Sarcoplasm

• Sarcoplasmic reticulum

• Myofibril

Muscle contraction is stimulated when this specific neurotransmitter is released into the synaptic cleft. What is the name of this neurotransmitter?

• Neurotensin

• Acetylcholine

• Cholecystokinin

• Norepinephrine

The filaments will slide past one another, overlapping one another, causing the ____________________________ to shorten. As many _____________________ shorten, the entire muscle fiber will shorten. Which of the terms below should be in the blanks?

• Myofibrils

• Sarcoplasm(s)

• Sarcomere(s)

• Synaptic cleft

The ______ extends inward from the epimysium; surround the fascicles.

• Fascia

• Fascicle

• Epimysium

• Perimysium

Each muscle cell (fiber) is covered by a connective tissue layer

• Fascia

• Fascicle

• Epimysium

• Endomysium