1. What causes the autorhythmicity or action potentials of the nodal cells? a. A decrease in chloride permeability b. A gradual
calcium efflux or movement out of the cell c. A gradual depolarization of the cell membrane until threshold is reached d. A gradual repolarization of the cell membrane until threshold is reached
The rhythm of the heartbeat is controlled by the pacemaker of the heart called the sino-atrial node.
The SA node generates action potentials which trigger the contraction and relaxation of the atrium and ventricles. The membrane potential generation initiates by the depolarization of the cell membrane when the L type of Ca⁺² ions opens up and calcium ions enter the cell.
This depolarizes the cell until the potential threshold is reached which lies between the -40 and -30 mV.
The wolves helped the ecosystem. I know this because of this sentence: The entire ecosystem became degraded until wolves became protected when they were determined to be an endangered species.
The knowledge obtained when scientists answer one question often generates other questions or proves useful in solving other questions. Scientists gather information and answer questions collectively known as the scientific method.
