Question Video: Identifying Haploid Cells in the Seminiferous Tubules of the Testes | Nagwa Question Video: Identifying Haploid Cells in the Seminiferous Tubules of the Testes | Nagwa

Question Video: Identifying Haploid Cells in the Seminiferous Tubules of the Testes Biology

The figure shows a drawing of a cross section of the seminiferous tubules in the testes. Identify the cells that are haploid.

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Video Transcript

The figure shows a drawing of a cross section of the seminiferous tubules in the testes. Identify the cells that are haploid. (A) A and C. (B) B and C. (C) B, C, and D. (D) C only. Or (E) C and E.

One seminiferous tubule has been represented here as the large, circular structure in the center of this diagram. The seminiferous tubules make up the bulk of the testes in human biological males and are the location of sperm production. And we can also see the edges of two other seminiferous tubules on the left of the diagram here.

Sperm production is often called spermatogenesis. Spermatogenesis functions to convert primary germ cells into mature sperm cells. Primary germ cells are diploid cells. The mature sperm cells they are converted into are haploid. This conversion involves a special type of cell division called meiosis that halves the number of chromosomes in a cell.

You may recall that a diploid cell has two sets of chromosomes like most other body cells. This is often represented as two n. The haploid cells that are produced through meiosis, on the other hand, have half this number of chromosomes. Haploid cells are often represented as n. The mature sperm cells that are the final product of spermatogenesis are haploid gametes. The main function of a sperm cell is to fuse with another haploid gamete, the egg cell, in fertilization. Fertilization produces a diploid zygote with two sets of chromosomes, ready to develop into a fully formed human.

Let’s have a go at labeling some of the cells that we can see in the seminiferous tubule in the center of the diagram. In the middle of each seminiferous tubule is a space called the lumen. The seminiferous tubules of a biological male who has begun puberty tell us a story of sperm production. We can see sperm cells at most of the different stages of development that follow the initial primary germ cell stage.

The cells that are eventually produced from these primary germ cells following the birth of the male are found furthest from the lumen and are called spermatogonia, or a singular spermatogonium. These cells are diploid as they were produced through mitosis and have not yet begun meiosis. These spermatogonia enter meiosis to eventually produce haploid spermatids. The spermatids are located closer to the lumen of the seminiferous tubule than the spermatogonia. The spermatids then differentiate into haploid mature sperm cells. The mature sperm cells can be released into the lumen.

We can be fairly confident that the correct answer is therefore (B), as the two cells labeled B and C are both haploid. To make sure, let’s check that the other cells that have been labeled on this diagram are not haploid too. The seminiferous tubules also contain diploid cells called Sertoli cells. One of the functions of Sertoli cells 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. A specific example of interstitial cells in the testes is Leydig cells, which are also diploid cells. Leydig cells are responsible for producing and secreting the hormone testosterone. This confirms that the haploid cells in the testes are spermatids and mature sperm cells. So, the correct answer to this question is (B), B and C.

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