Look at this Quizlet study guide it'll help.
https://quizlet.com/98515495/buoyancy-in-fishes-flash-cards/
The slightest change in pH can destroy the substance or organism. The pH of a cell's interior helps regulate the cell's chemical reactions. For example, the pH of blood is 7.4, if blood falls to 6.8 or lower or 8.2 or higher, it results in death.
I think Autorhythmic fibers are fibers that are self excitable or on their own for example some cardiac muscle. They repeatedly generate action potentials that trigger heart contractions.They continue to stimulate a heart to beat even when it is removed from the body. In comparison to contractile fibers, autorhythmic fibers are self excitable and do not require nervous system stimulation to trigger contractions. Contractile fibers have stable resting membrane potentials of -90mV, when a contractile fibers reaches threshold by action potential, the voltage gated fast sodium ions channels will open.
