Contraction elicited by a single brief stimulus is called:
a. A twitch
b. Temporal summation
c. Multiple motor unit summation
d. Fused tetanus

Verified step by step guidance

1. Step 1: Understand the terminology related to muscle contractions. A 'twitch' is the response of a muscle to a single brief stimulus, resulting in a quick contraction and relaxation.
2. Step 2: Review the other options to differentiate them: 'Temporal summation' refers to multiple stimuli in rapid succession causing increased contraction strength; 'Multiple motor unit summation' involves recruiting more motor units to increase contraction force; 'Fused tetanus' is a sustained contraction with no relaxation due to very rapid stimuli.
3. Step 3: Identify that the question asks specifically for the contraction caused by a single brief stimulus, which matches the definition of a 'twitch'.
4. Step 4: Confirm that the other options involve multiple stimuli or motor units, which do not fit the description of a single brief stimulus contraction.
5. Step 5: Conclude that the correct term for contraction elicited by a single brief stimulus is 'a twitch'.

Key Concepts

Muscle Twitch

A muscle twitch is the brief contraction of muscle fibers in response to a single, quick stimulus. It consists of three phases: latent, contraction, and relaxation. This basic unit of muscle contraction helps in understanding how muscles respond to neural signals.

Temporal Summation

Temporal summation occurs when multiple stimuli are delivered in rapid succession to a muscle, causing the contractions to add up and produce a stronger overall contraction. It explains how muscle tension increases with stimulus frequency.

Multiple Motor Unit Summation

Multiple motor unit summation refers to the recruitment of additional motor units to increase muscle contraction strength. This process allows for graded control of muscle force by activating more muscle fibers as needed.