Answer:
The length-tension relationship in a contracting skeletal muscle is depicted in a graph that shows the relationship between the tension generated by the muscle and the length of the sarcomere. The optimal length of a sarcomere is the length at which it can generate the most tension.
At optimal length, the actin and myosin filaments overlap optimally, which allows for the greatest number of cross-bridges to form between actin and myosin. This results in the maximum number of myosin heads actively pulling on the actin filaments, generating the greatest amount of tension possible in the muscle. This is also known as the maximum isometric tension.
As the muscle is stretched beyond its optimal length, the actin and myosin filaments begin to pull apart, which reduces the number of cross-bridges that can form. This decreases the number of myosin heads actively pulling on the actin filaments, which reduces the amount of tension generated by the muscle. This is known as the descending limb of the length-tension relationship.
Conversely, as the muscle is shortened below its optimal length, the actin and myosin filaments begin to overlap too much and myosin heads start to interfere with one another, producing less overall tension. This is also associated with a decrease in the number of cross-bridges that can form and generate force. This is known as the ascending limb of the length-tension relationship.
In summary, the length-tension relationship in a contracting skeletal muscle describes the relationship between the tension developed by the muscle at different sarcomere lengths. At optimal sarcomere length, the maximum number of cross-bridges can form, producing the greatest amount of tension. When the muscle is either shortened or stretched beyond this optimal length, the number of cross-bridges decreases, causing less tension to be generated.
Step-by-step explanation:
hope this helps