它是人體的結構和功能單位。共約有40萬–60萬億個，細胞的平均直徑在10–20微米之間。除成熟的紅血球和血小板外，所有細胞都有至少一個細胞核，是調節細胞作用的中心。最大的是成熟的卵細胞，直徑在0.1毫米以上；最小的是血小板，直徑只有約2微米。人體由體細胞 + 生殖細胞組成，體胞細含有的染色體數是生殖細胞的2倍，人體除生殖細胞外，其他細胞都是有23對染色體組成（血液中某些不含細胞核的細胞除外）
It is the basic structural and functional unit of the human body.
There are approximately 40 to 60 trillion cells in the body, with an average diameter ranging between 10 and 20 micrometers.
Except for mature red blood cells and platelets, all cells contain at least one nucleus, which serves as the control center regulating cellular activities.
The largest cell is the mature egg cell (ovum), with a diameter exceeding 0.1 millimeters, while the smallest is the platelet, with a diameter of only about 2 micrometers.
The human body is composed of somatic cells and germ cells.
Somatic cells contain twice the number of chromosomes compared to germ cells.
In humans, excluding germ cells, most cells have 23 pairs of chromosomes (with the exception of certain blood cells that lack a nucleus).