Muscle Twitch (Chapter 9) Flashcards

Questions and Answers

What is a muscle twitch?

A simple contraction resulting from a muscle fiber's response to a single action potential from a motor neuron (correct)

A relaxation of the muscle after an extended contraction

A contraction that occurs due to hormonal stimulation

A type of complex muscle contraction involving multiple muscle fibers

What does a myogram represent?

It shows how the twitch is observed and recorded, usually as a line tracing contraction activity.

List the three periods of a muscle twitch.

Latent period, period of contraction, period of relaxation.

What happens during the latent period of a muscle twitch?

Events of excitation-contraction coupling occur with no muscle tension seen. Signup and view all the answers

What characterizes the period of contraction in a muscle twitch?

Cross bridge formation occurs, and tension increases. Signup and view all the answers

What occurs during the period of relaxation?

Ca2+ reenters into the sarcoplasmic reticulum, and tension declines to zero. Signup and view all the answers

Why do different muscles exhibit variations in the strength and duration of twitches?

Due to variations in metabolic properties and enzymes between muscles. Signup and view all the answers

Study Notes

Muscle Twitch Overview

A muscle twitch is the simplest form of contraction triggered by a single action potential from a motor neuron.
The contraction occurs rapidly followed by a relaxation phase.

Myogram

Myograms are charts used to observe and record muscle twitches.
They provide a visual representation of contraction activity over time.

Phases of Muscle Twitch

Muscle twitches consist of three main periods:
- Latent Period: Initial phase where excitation-contraction coupling occurs; no muscle tension detected.
- Period of Contraction: Characterized by cross bridge formation leading to an increase in muscle tension.
- Period of Relaxation: Reentry of calcium ions (Ca2+) into the sarcoplasmic reticulum results in tension declining to zero.

Characteristics of Muscle Twitches

Variations in the strength and duration of muscle twitches are observed due to differing metabolic properties and enzyme distributions among muscle types.
Example: Eye muscles produce rapid and brief contractions, while larger muscles, such as the calf, have slower contractions with longer duration.

Comparative Duration of Twitch Responses

Muscles can display different relative durations in twitch responses, influenced by their specific metabolic characteristics.

Description

Explore the key concepts and definitions related to muscle twitches from Chapter 9. This quiz includes terms like 'muscle twitch', 'myogram', and the three periods of muscle twitch. Test your understanding of how muscle contractions are initiated and recorded.