Sodium and chloride also help to determine the resting potential. Sodium is positive and has a concentration gradient set up to flow INTO the cell, and chloride is negative and has a concentration gradient set up to flow INTO the cell. The resting conductance for these two ions is less than that of potassium, but is not zero. Their story (concentration gradient + electrical gradient) is very similar to that of potassium. These ions together determine the resting potential of the cell.
1 the U.S.A. ranks number 3 in the list of countries by population. 2  The population density in the United States is 35 per Km2 (92 people per mi2). 3  The total land area is 9,155,898 Km2 (3,535,111 sq. miles) 4  82.5 % of the population is urban (268,012,791 people in 2016)  The median age in the United States is 38.1 years.
For humans, population density is the number of people per unit of area, usually quoted per square kilometer or square mile (which may include or exclude, for example, areas of water or glaciers).Commonly this may be calculated for a county, city, country, another territory, or the entire world.f only the Earth's land area of 150 million km 2 (58 million sq. miles) is taken into account, then human population density increases to 47 per km 2 (120 per sq. mile). This includes all continental and island land area, including Antarctica.