The contractile vacuole acts to regulate quantity of water in a cell. In freshwater environments the concentration of solutes inside the cell is higher than outside the cell (i.e., the environment is hypotonic).he contraction of the contractile vacuole and the expulsion of water out of the cell is called systole. Water always flows first from outside the cell into the cytoplasm, and is only then moved from the cytoplasm into the contractile vacuole for expulsion.
Induced coma. A barbiturate-induced coma, or barb coma, is a temporary coma (a deep state of unconsciousness) brought on by a controlled dose of a barbiturate drug, usually pentobarbital or thiopental.
1. Voluntary Control: overide by cerebral cortex (but is limited, e.g. can't hold breath indefinitely) 2. Mechanical Control: Stretch receptors in the lungs (sets basic respiratory rhythm and depth) 3. CO2 and O2 Levels: Chemoreceptors in brain (sensitive to small increases of CO2 and general increases of O2.