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. Identify the key terms in the question: 'contraction', 'single brief stimulus'.
2. Understand that a 'single brief stimulus' refers to a quick, isolated electrical impulse to a muscle.
3. Recall that a 'twitch' is the response of a muscle to a single, brief stimulus, resulting in a quick contraction and relaxation cycle.
4. Differentiate between the options: 'temporal summation' involves multiple stimuli over time, 'multiple motor unit summation' involves recruiting more motor units, and 'fused tetanus' involves continuous stimuli leading to a sustained contraction.
5. Conclude that the correct term for a contraction elicited by a single brief stimulus is 'a twitch'.

Key Concepts

Twitch

A twitch is a single, brief contraction of a muscle fiber or a group of muscle fibers in response to a single stimulus. It consists of a latent period, a contraction phase, and a relaxation phase. This concept is fundamental in understanding muscle physiology and how muscles respond to stimuli.

Temporal Summation

Temporal summation occurs when multiple stimuli are applied to a muscle in rapid succession, leading to an increased force of contraction. This happens because the muscle does not have enough time to fully relax between stimuli, resulting in a stronger overall contraction. It is essential for understanding how muscles can generate greater force under certain conditions.

Motor Unit Summation

Motor unit summation refers to the recruitment of additional motor units to increase muscle contraction strength. When a muscle is stimulated, not all motor units are activated simultaneously; instead, they are recruited based on the strength of the stimulus. This concept is crucial for understanding how muscles can vary their force output depending on the demands placed on them.