Answer:
The myofibrils are the contractile organelles in the muscle fibers.
The answer is <span>hy<span>pothalamus.</span></span>
<span>The hy<span>pothalamus <span>regulates the </span></span></span><span>sympathetic nervous system, part of </span><span> autonomic nervous system, </span><span>associated with fight-or-flight </span><span>responses.
During stress situations the sympathetic nervous system is more activated, causing a response of either run or fight. Because of that, the body needs to be prepared and there will be elevated blood pressure (the blood is going more to the skeletal muscle, heart,etc), dilated pupils (for better peripheral vision) and increased respiration. </span>
Gastric secretion begins during the cephalic stage and ends during the intestinal phase. The regulation of stomach secretion is divided into three phases which are cephalic, gastric and intestinal. The cephalic stage occurs when the food is been eaten. Gastric secretions are stimulated by three chemicals which are acetylcholine, histamine and gastrin. The gastric phase occurs in the stomach while the intestinal phase occurs in the small intestines.<span />
