Question

In an isotonic muscle contraction, a. the length of the muscle remains constant. b. the muscle tension remains constant. c. both muscle length and tension are changed. d. movement of bones does not occur.

Short answer

In an isotonic muscle contraction, the muscle tension remains constant (option b) while the muscle changes its length, allowing movement of bones to occur.

Step-by-step solution

Understanding isotonic muscle contractions

In an isotonic muscle contraction, the muscle changes its length, while the tension in the muscle remains constant.

Analyzing the options

Now let's analyze each of the given options and match them with the characteristics of isotonic muscle contractions mentioned in Step 1. a. the length of the muscle remains constant. - This option contradicts our understanding of isotonic muscle contractions, where the muscle length changes. So, this option is incorrect. b. the muscle tension remains constant. - This option matches our understanding of isotonic muscle contractions, where tension remains constant while the length changes. So, this option is correct. c. both muscle length and tension are changed. - In isotonic muscle contractions, tension remains constant while the length changes. So, this option is incorrect. d. movement of bones does not occur. - In isotonic muscle contractions, movement of bones does occur because the muscle length changes, generating movement. So, this option is incorrect.

Select the correct option

Based on the analysis in Step 2, the correct option for the given question is: b. the muscle tension remains constant.

Key concepts

Muscle Physiology

Muscle physiology is the study of the functions and activities of muscles, the fibrous tissues in the body responsible for movement. In simple terms, muscles react to signals from the nervous system by contracting, which then pulls on bones to create movement. There are three types of muscles in the human body: skeletal, smooth, and cardiac.

Skeletal muscles, which are under our voluntary control, are the ones usually involved in isotonic contractions - a type of muscle movement where the muscle changes length. During such contractions, these muscles attach to the skeleton via tendons, and by shortening, they move the bones they're connected to, allowing us to perform a wide variety of actions, from lifting objects to running.

Muscle Tension

Muscle tension refers to the force generated by a muscle or group of muscles when they contract. Think of it like the amount of work your muscles are doing at any given time. During an isotonic contraction, the muscle tension remains constant throughout the movement. What does this mean?

Even though a muscle may change length - shorten or lengthen - during an exercise, if the contraction is isotonic, the force produced and the workload on the muscle does not vary. That's why when you lift a weight in a bicep curl, for example, the resistance feels the same from the start of the lift to the end, even though your muscle is shortening.

Muscle Contraction

Understanding muscle contraction is key to deciphering how our bodies move. Muscle contraction occurs when muscle fibers generate tension through a process known as cross-bridge cycling, which is powered by ATP, the energy currency of the cell.

There are generally two categories of contractions: isotonic and isometric. Isotonic contractions, which can be broken down into concentric (muscle shortening) and eccentric (muscle lengthening) movements, allow us to perform everyday tasks like walking or lifting. On the contrary, isometric contractions occur when muscle length remains the same while muscle tension increases, like when holding a static position.

Human Physiology

Human physiology is the scientific study of the functions and mechanisms of the human body. It covers everything from the cellular processes that keep us alive to the way our muscles and bones work together to enable movement.

In the context of isotonic muscle contractions, human physiology looks at how these movements fit into the bigger picture of bodily functions. For example, it involves understanding how isotonic exercises influence cardiovascular health, metabolism, and muscle growth as well as their impact on systemic factors such as hormone levels and neurological health.