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How Is Cell Division Involved in Growth?

The endocrine system in the body is primarily responsible for growth. Part of this system involves cell growth and division. Cells are constantly growing. Each cell continuously goes through the cell cycle, where a parent cell expands, duplicates and splits into two daughter cells, and the process repeats. This is called cell division. As each new generation of cells grows, such as in a human body, the body grows as well.

  1. Cell Cycle

    • The cell cycle consists of four distinct phases. The first three are gap 1, synthesis, and gap 2, which are collectively known as interphase. The final phase is mitosis. During gap 1, the cell increases in size. During synthesis, the DNA within the cell is replicated. During gap 2, the cell continues to grow and prepares for mitosis but will halt the process if it discovers that DNA has been damaged during synthesis. During mitosis, the parent cell splits into two daughter cells completing the process. The cell cycle in humans lasts roughly 20 to 24 hours.

    The First Division

    • When a sperm and an egg fuse together, the first cell of a new life is created. This single cell replicates and multiplies into a so-called blast, which is a multi-cellular ball. Cell division continues as the blast grows into an embryo and continues still to become a baby. This single fertilized cell goes through many cell divisions over years to grow into an adult with trillions of cells.

    Why Cells Divide

    • Cells cannot just continue to grow because the inside of a cell grows faster than the cell membrane. As the inside of a cell grows, the membrane is stretched thinner and thinner. In order to keep up, the cell divides. This also helps the cell membrane because it is responsible for passing food and oxygen through to the inside. When the cell divides into daughter cells, each individual cell needs to provide food and oxygen to less area.

    Hayflick Limit

    • The Hayflick limit was discovered by Leonard Hayflick in 1965. He found that the human limit of cell division is around 52, but in a fetus, the number ranges anywhere from 40 to 60 times. As cells near this number of divisions, they show greater signs of old age. The number of times cells divide decreases with age, which shows the correlation between the two.

    When Growing Stops

    • In young people, cells divide and the body grows. Why growth stops has little to do with cell division. The endocrine glands in the body are responsible for halting growth. When a body fully matures, these glands become less active. Cells in the body are still dividing, but the body is not growing anymore.

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