With the help of a diagram, Describe this conductive system how the AP spread throughout the muscle.

Answer 1

In a muscle, action potentials are spread through a network of conductive fibers called the T-tubules and sarcoplasmic reticulum. The AP spread in a coordinated manner to allow for synchronized muscle contraction.

The diagram should display a skeletal muscle cell with T-tubules extending into the cell. At the end of each T-tubule is a terminal cisterna of the sarcoplasmic reticulum. The sarcoplasmic reticulum is a network of tubules that store and release calcium ions during muscle contraction.

When an action potential reaches the T-tubules, it triggers the release of calcium ions from the sarcoplasmic reticulum. The calcium ions then bind to the protein troponin on the actin filaments, exposing the myosin binding sites. This allows for the myosin heads to bind to actin and pull the filaments closer together, resulting in muscle contraction.

The diagram should illustrate this process of excitation-contraction coupling, showing how the action potential spreads through the T-tubules and triggers the release of calcium ions from the sarcoplasmic reticulum, leading to muscle contraction.