Video Transcript
What cells are produced as a result
of the first meiotic division inside the seminiferous tubules?
This question is asking us to
identify the cells that are produced from the first meiotic division within the
seminiferous tubules of a biological male’s testes. The seminiferous tubules are the
site of sperm production, which is otherwise known as spermatogenesis. Overall, spermatogenesis aims to
convert diploid primary germ cells into haploid mature sperm cells, which might be
able to fertilize a biological female’s egg cell. Let’s take a look at an overview of
the different stages in spermatogenesis so we can work out what these cells that are
produced in the first division of meiosis are.
The first stage of spermatogenesis
is known as the multiplication phase, which begins before birth while the biological
male is still in utero. It includes many mitotic divisions
of the diploid primary germ cells. Remember that mitosis is a type of
cell division where one cell divides to produce two new cells that are genetically
identical. Eventually, these mitotic divisions
form cells called spermatogonia, one of which is called a spermatogonium. A large number of these diploid
spermatogonia are formed just following birth of the biological male. Spermatogonia then enter the second
stage of spermatogenesis, the growth phase. The spermatogonia also divide by
mitosis and differentiate into diploid primary spermatocytes.
During the growth phase, the
primary spermatocytes replicate their genetic information so that they now have 46
replicated chromosomes in each cell. This means that they are ready for
meiosis. Remember that meiosis is the type
of cell division that produces four genetically different cells with half the number
of chromosomes. It’s important in the production of
gametes, which are egg cells in biological females and in biological males, the
sperm cells that are produced through spermatogenesis in the seminiferous
tubules. The primary spermatocytes undergo
meiosis during the maturation phase of spermatogenesis. You may recall that meiosis
consists of two stages: meiosis I and meiosis II. It’s important to recall that
meiosis halves the number of chromosomes in the developing sperm cells.
In meiosis I, which is the first
meiotic division that we’re being asked about in this particular question, the
diploid primary spermatocytes are converted into haploid secondary
spermatocytes. In meiosis II, the secondary
spermatocytes are converted into spermatids, which are also haploid. The spermatids then enter the final
stage, metamorphosis, during which they develop into mature sperm cells. Therefore, the cells that are
produced from the first meiotic division inside the seminiferous tubules are
secondary spermatocytes.
