Action potentials traveling down the plasma membrane of a muscle fiber will next reach the _____ after leaving the T tubules.
A) mitochondria
B) neuromuscular junction
C) cytoskeletal system
D) sarcoplasmic reticulum
E) endomembrane system

Question

Action potentials traveling down the plasma membrane of a muscle fiber will next reach the _____ after leaving the T tubules.  
A) mitochondria
B) neuromuscular junction
C) cytoskeletal system
D) sarcoplasmic reticulum
E) endomembrane system

Quizplus · Accepted Answer

The action potentials will travel to the sarcoplasmic reticulum (SR) after leaving the T-tubules. This causes the release of calcium ions from the SR, which then bind to the troponin-tropomyosin complex on the thin filaments, leading to muscle contraction.

Action Potentials Traveling Down the Plasma Membrane of a Muscle