Marinades don't penetrate nor do acids tenderize,except for making the outer mushy. Papain, if not time controlled, will turn the meat to mush also. Sorry to be the bearer of bad news but at least you have something that will tenderize. Nothing is going to make tri tip melt literally like butter.
The diaphragm is the major muscle responsible for breathing. It is a thin, dome-shaped muscle that separates the abdominal cavity from the thoracic cavity. During inhalation, the diaphragm contracts, so that it's centre moves caudally (downward) and its edges move rostrally (upward).
In human physiology, the muscles of respiration are those muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity.The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing.n human physiology, the muscles of respiration are those muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity.