Muscle Contraction Lab Report

Thato’s muscle had remained unused for 6 weeks. Once the cast is removed and he steps down from the examination table, his muscle begins to contract. Due to this 6 week period of rest, the muscles initial strength of contraction may be significantly low as compared to its strength a few minutes later. The strength of contraction of his muscle increases to a plateau, which is termed the staircase effect. Due to his muscles low initial strength of contraction, Thato loses his balance and falls.

1.2 Yes, skeletal muscles can contract without shortening. Isometric muscle contraction is when the muscle does not shorten during contraction. Hence, the muscle contracts against a force transducer without decreasing the muscle length.

Question 2
By means of a coupling mechanism, sodium ions are able to pull other substances along with them through a cell membrane. A carrier protein situated in the cell membrane serves as an attachment point for the co-transport of the sodium ion as well as the other substance. Once attached, both the sodium ion and the other substance are transported to the interior of the cell together. This is due to the diffusion energy gradient of the sodium ion.

Examples of co-transport:
Sodium-glucose co-transport mechanism
The sodium ion and glucose both attach to the exterior side of the carrier protein. Once attached, a conformational change occurs, and the sodium ion and glucose are transported to the interior of the cell together. Transport is made possible by energy from the sodium ion due to a large concentration gradient.

Sodium co-transport of amino acids
This occurs in the same manner as that of glucose, except that a different set of transport proteins are