Question

the fluid in the sarcoplasmic reticulum contains a high concentration of _________ ions, which are released when an action potential occurs. sodium iron potassium calcium phosphorus question 14 1 pts the striations that give skeletal muscle its characteristic striped appearance are produced, for the most part, by: the \cocked\ positions of the heads of the thick filaments the t tubules a difference in the thickness of the sarcolemma the sarcoplasmic reticulum the arrangement of myofilaments

Explanation:

The sarcoplasmic reticulum stores calcium ions and releases them upon an action potential for muscle contraction. The striations in skeletal muscle are due to the arrangement of myofilaments (actin and myosin).

Answer:

Question 1: D. calcium
Question 2: E. the arrangement of myofilaments