Action potential is a mechanism of transfer of ions across the plasma membrane down their elctrochemical gradient. Action potential is regenerated by the influx of ions such as sodium in case of voltage gated sodium channels. The voltage gated channels can be either open or closed depending on the action potential. Depolarization of membrane leads to the opening of these channels that allow the sodium ions to enter the cell down their electrochemical gradient. The threshold of action potential is reached when the entry of sodium ions out reach the exit of potassium ions from the cell. This leads to the generation of action potential.
The respiratory system of the birds
Behavioral isolation occurs when a subset of a particular species slowly undergoes changes in its behavior ordinarily due to traveling to different geographical regions.
Answer: Two pathways come from the heart: The pulmonary circulation is a short loop from the heart to the lungs and back again. The systemic circulation carries blood from the heart to all the other parts of the body and back again.
Explanation: