Action potential and Na+. It is a fact that Na+ ions cross the membrane and enter the cell during the rising phase of the action potential. The process happens because Na ions channels are open. Then the ions channels becomes inactivated/closed for a while. What happens to the Na+ ions that entered the cell?
Product (mathematics) In mathematics, a product is a number or a quantity obtained by multiplying two or more numbers together. For example: 4 Ã 7 = 28 Here, the number 28 is called the product of 4 and 7. The product of 6 and 4 will be 24, because 6 Ã 4 = 24.
Ordinal Number. In common usage, an ordinal number is an adjective which describes the numerical position of an object, e.g., first, second, third, etc. In formal set theory, an ordinal number (sometimes simply called an ordinal for short) is one of the numbers in Georg Cantor's extension of the whole numbers. An ordinal number is defined as the order type of a well ordered set (Dauben 1990, p. 199; Moore 1982, p. 52; Suppes 1972, p. 129).