Video Transcript
The figure shows a drawing of a
cross section of the seminiferous tubules in the testes. Which cell is a spermatogonium? (A), (B), (C), (D), or (E).
The seminiferous tubules, one of
which has been represented here as the large circular structure in the center of
this diagram, are coiled tubes that make up the bulk of the testes in biological
males. We can also see the edges of two
other seminiferous tubules on the left of the diagram.
The seminiferous tubules are the
site of sperm production, which is sometimes called spermatogenesis. Overall, spermatogenesis converts
diploid primary germ cells, which are sometimes called primordial germ cells, into
haploid mature sperm cells.
Let’s have a go at labeling some of
the different cells that can be identified in this diagram. In the middle of each seminiferous
tubule is a space called the lumen. Surrounding the lumen in the
seminiferous tubule of a biological male who has begun puberty, there are sperm
cells at various stages of development that follow the initial primary germ cell
stage. The cells that are eventually
produced from many mitotic divisions of the primary germ cells following the birth
of the male are located furthest from the lumen and are called spermatogonia. A single spermatogonia is called a
spermatogonium, which has been labeled with the letter D on this diagram, suggesting
that this is the correct answer to this question.
Let’s double-check by identifying
the other cells that have been labeled. The spermatogonia enter a type of
cell division called meiosis, which halves the number of chromosomes in these
diploid cells to eventually convert them into haploid cells called spermatids. The spermatids, one of which has
been labeled with the letter B, are located closer to the lumen of the seminiferous
tubule.
The spermatids then differentiate
into haploid mature sperm cells, one of which has been labeled with the letter C,
that can be released into the lumen.
The seminiferous tubules also
contain cells called Sertoli cells, one of which has been labeled here with the
letter A. One of the functions of a Sertoli
cell is to secrete fluids to nourish and support the developing sperm cells.
Interstitial cells can be located
in various regions of the body, between the functional cells of any particular
tissue. Specific examples of interstitial
cells in the testes are called Leydig cells, one of which has been labeled here with
the letter E. Leydig cells are responsible for
producing and secreting the hormone testosterone.
Having identified all of the
labeled cells in this diagram, we can confirm which cell is a spermatogonium. The letter that identifies a
spermatogonium is D.
