Exercise Science & Anatomy Flashcards

Which of the following best defines 'motor unit'?

Answer: A motor neuron and all the muscle fibers it innervates

A motor unit consists of a single motor neuron and all of the skeletal muscle fibers it innervates and controls.

What is the primary fuel source during low-intensity, long-duration aerobic exercise?

Answer: Stored fat (triglycerides)

At low intensities, the aerobic system predominantly oxidizes stored fat (triglycerides) for sustained energy production.

What anatomical term describes movement away from the body's midline?

Answer: Abduction

Abduction describes movement of a limb away from the body's midline, such as raising the arm out to the side.

Which structure transmits nerve impulses from motor neuron to muscle fiber?

Answer: Neuromuscular junction (NMJ)

The neuromuscular junction (NMJ) is the synapse where a motor neuron releases acetylcholine to stimulate muscle fiber contraction.

What occurs during the 'all-or-none' principle of muscle fiber contraction?

Answer: A muscle fiber contracts maximally or not at all

The all-or-none principle states that when a muscle fiber is stimulated above threshold, it contracts with full force; below threshold, it does not contract at all.

Which muscle action occurs when the muscle produces force while lengthening?

Answer: Eccentric

An eccentric contraction occurs when a muscle generates force while lengthening, such as lowering a weight under control.