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[No title] Pale spermatogonium A is characterised by relatively large cells with a pale-staining cytoplasm and nucleus. Spermatogonium A is the continuous source of spermatogenic cells, self-renewal takes place by mitosis. Spermatogonium B are large cells with pale-staining cytoplasm and nucleoplasm. www.rivm.nl /fishtoxpat/tesarch3bo.htm   (777 words)

Spermatogenesis then only one spermatogonium proceeds through meiosis and we are still left with the same number of spermatogonia that we started with. So the various cells in the progression from spermatogonium to spermatozoa lie in obvious layers through the tubules. Please note that the lumen of the seminiferous tubule is at the top of this drawing, while the outer edge of the tubule is at the bottom. faculty.stcc.edu /AandP/AP/AP2pages/reprod/spermato.htm   (618 words)

Physi Sperms, the male gametes, are produced by the Leydig cells of the seminiferous tubules in the testes. After a number of mitosis, differentiation begins to appear and the resultant daughter cell is called a primary spermatocyst which is ready to undergo meiosis. One clone from each original spermatogonium escapes from the mitosis-differentiation cycle and reverts to a primitive spermatogonium which is capable to carry out its own cycle of mitosis later. library.thinkquest.org /C005559/physi.htm   (2629 words)

Ed's Histology Notes: Male The spermatogonium, the stem cell of the prepubertal child, becomes at puberty the type A spermatogonium which, at each division, gives rise to one type A spermatogonium (stays at the bottom, of course) and one type B spermatogonium which will become a bunch of primary spermatocytes. Don't try to pick them out in sections; their nuclei are also wiggly-squiggly but smaller than those of primary spermatocytes (why?) They divide in turn, again by meiosis, but with no S-phase, to produce spermatids, easily recognizable by their location near the lumen and their small size. All the progeny of one spermatogonium are supposedly connected by intercytoplasmic bridges until they become real sperms; this keeps them from sloughing off early. www.pathguy.com /manhisto.htm   (2476 words)

Spermatocyte - Wikipedia, the free encyclopedia A spermatocyte is a male gametocyte which is derived from a spermatogonium. Initially, a spermatogonium divides by mitosis into two so-called primary spermatocytes. A primary spermatocyte is also diploid, and, in turn, gives place by meiosis to two secondary spermatocytes, which this time are haploid. en.wikipedia.org /wiki/Spermatocyte   (186 words)

Spermatogenesis The first comprises the cells from the spermatogonium up to and including the secondary spermatocyte and is termed spermatocytogenesis. In the heteronymous division the cytoplasmic division is not completed; the daughter cells stay bound together through thin cytoplasmic bridges. Also in the subsequent meiosis the cytoplasmic division is incomplete, so that from one spermatogonium a network of daughter cells arises that doubles in size in each generation. www.embryology.ch /anglais/cgametogen/spermato03.html   (611 words)

[No title]   (Site not responding. Last check: 2007-10-10) spermatid to spermatogonium to spermatocyte to sperm C. spermatogonium to spermatocyte to spermatid to sperm D. spermatogonium to spermatid to spermatocyte to sperm Which of these is not a function of male supporting cells (=sustentacular cells or Sertoli cells)? www.wsu.edu /~jmallatt/biol315/LectureTest4from2005.doc   (2655 words)

Functional demonstration of the ability of a primary spermatogonium as a stem cell by tracing a single cell destiny in ... Functional demonstration of the ability of a primary spermatogonium as a stem cell by tracing a single cell destiny in Xenopus laevis. In Xenopus, although primary spermatogonium (PG), the largest cell in the testis, is believed to be spermatogonial stem cell by histological observations, functional evidence has never been obtained. These results suggested that isolated PG from the cultured testes had the ability as stem cells, and that purification of the spermatogenic stem cells became reliable in Xenopus. lib.bioinfo.pl /pmid:17026716   (2666 words)

THE INTERACTIVE FLY, Drosophila These three stem cells undergo unequal cell divisions: the parental stem cells remain attached to the hub, while the three daughter cells (one spermatogonium and two cyst cells) detach and initiate a program of differentiation (Castrillon, 1993). This group of three daughter cells, one germline and two somatically derived cells, is the early cyst. The transformation of a single spermatogonium to 64 sperm occurs within a thin envelope formed by two cyst cells. www.sdbonline.org /fly/cytoskel/tubet2-1.htm   (2777 words)

Lecture 12 Reveiw Quiz GnRH binds to receptors on the surface of Leydig cells and via a calcium second messenger system, testosterone production and secretion is increased. In the bull, spermatogenesis involves the mitotic divisions of the sequence: Spermatogonium A to I to B and finally a primary spermatocyte. In the bull, there is the potential to produce 64 round spermatids from each type A spermatogonium that enters into spermatogenesis. www.wisc.edu /ansci_repro/lec/quizes/lec_12quiz.htm   (573 words)

SparkNotes: SAT Biology: Spermatogenesis and Oogenesis The basic function of spermatogenesis is to turn each one of the diploid spermatogonium into four haploid sperm cells. During interphase before meiosis I, the spermatogonium’s 46 single chromosomes are replicated to form 46 pairs of sister chromatids, which then exchange genetic material through synapsis before the first meiotic division. First of all, oogenesis only leads to the production of one final ovum, or egg cell, from each primary oocyte (in contrast to the four sperm that are generated from every spermatogonium). www.sparknotes.com /testprep/books/sat2/biology/chapter7section2.rhtml   (401 words)

Spermatogenesis - Male reproductive physiology As a single spermatogonium divides and matures, its descendants remain tied together by cytoplasmic bridges until the late spermatid stage. The estimated number of spermatids formed from a single spermatogonium is 512. In humans, it takes an average of 74 days to form a mature sperm from a primitive germ cell by this orderly process of spermatogenesis. www.health.am /sex/more/male_infertility_spermatogenesis   (1102 words)

ใบความรู้ที่  1   (Site not responding. Last check: 2007-10-10) เด็กชายแรกเกิด จะมี Spermatogonium อยู่ในหลอดสร้างอสุจิ (Seminiferous tubule) จำนวนมาก โดยSpermatogonium เปลี่ยนแปลงมาจาก Primordial germ cell Spermatogonium จะแบ่งเซลล์แบบ Mitosis ได้เซลล์ร่างกายจำนวนมากมาย เซลล์เหล่านี้จะเจริญมีขนาดใหญ่ขึ้น เรียก Primary spermatocyte เมื่อย่างเข้าสู่วัยรุ่น ได้รับฮอร์โมน; FSH จากต่อมใต้สมอง Primary spermatocyte จะแบ่งเซลล์แบบ; Meiosis ได้; Spermatid จำนวนมากมาย ซึ่งเจริญต่อไปเป็น; Sperm เมื่อตกเข้าสู่ท่อนำไข่ จะมีชีวิตไม่เกิน 48 ชั่วโมง เกิดขึ้นในรังไข่ โดยมีเซลล์กลุ่มหนึ่ง ซึ่งแต่ละเซลล์เรียก Oogonium เป็นเซลล์ดิพลอยด์เช่นเดียวกับ Spermatogonium เซลล์เหล่านี้จะแบ่งตัวแบบ Mitosis หลายครั้ง ทำให้ได้เซลล์ใหม่จำนวนมาก เมื่อเด็กหญิงแรกเกิด เซลล์เหล่านี้มีขนาดใหญ่ขึ้น เรียก Primary oocyte :มันจะมีกลุ่มเซลล์มาหุ้ม กลุ่มเซลล์นี้เรียก follicle cell เรียกรวมกันว่า; Follicle รังไข่ของเด็กหญิงแรกเกิดมี Primary oocyte ประมาณ 2 ล้านเซลล์ จนกระทั่งย่างเข้าสู่วัยรุ่น ได้รับฮอร์โมน FSH จากต่อมใต้สมอง จะแบ่งเซลล์แบบ Meiosisได้; Secondary oocyte ซึ่งจะตกเข้าสู่ท่อนำไข่ เมิ่อมี sperm มาเจาะเปลือกไข่ มันจะแบ่งเซลล์แบบ Meiosis2 ได้4 เซลล์ สลายไป 3 เซลล์ อีก1 เซลล์เจริญเป็นไข่ซึ่งมีชีวิตไม่เกิน 24 ชั่วโมง www.narinukul.ac.th /Teeraton/learn1tee.htm   (87 words)

Gametogenesis Summary Primordial germ cells are the stem cells that, via mitosis, supply both spermatogonia and oogonia. In humans, spermatogenesis starts with a diploid (2N) spermatogonium that carries the full genetic compliment of 46 chromosomes (22 autosomal pairs, one X and one Y sex chromosomes). The spermatogonium represents the germ cell line from which all sperm cells are derived. www.bookrags.com /Gametogenesis   (777 words)

Semen and sperm quality Individual sperm develop within the testicles from a cell called a spermatogonium. The spermatogonium divides to produce spermatocytes, which then develop into spermatids. The spermatid develops its familiar tail and the cell gradually acquires the ability to move by beating its tail. www.netdoctor.co.uk /menshealth/facts/semenandsperm.htm   (1427 words)

Immunohistochemical Study of Protein 4.1B in the Normal and W/Wv Mouse Seminiferous Epithelium -- Terada et al. 52 (6): ... Protein 4.1B on plasma membranes of Sertoli cells facing the spermatogonium. Immunoelectron microscopic localization of protein 4.1B in the mouse seminiferous epithelium with an anti-protein 4.1B antibody, an HRP-conjugated secondary antibody, and subsequent DAB staining. Protein 4.1B is expressed in the basal compartment of Sertoli cells, facing the spermatogonium (Sg) (dots). www.jhc.org /cgi/content/full/52/6/769   (3760 words)

The Ark of Life: The Germ Line A single spermatogonium enters the first meiotic division as a primary spermatocyte. Consequently, four haploid sperm result from each diploid spermatogonium. The utilization of all four haploid cells in the male is significant because the testis must produce millions of sperm simultaneously. www.ucalgary.ca /uofc/eduweb/virtualembryo/ark.html   (1721 words)

Visuals Unlimited Stock Photography: Late telophase stage of mitosis in a spermatogonium. The chromosomes are almost ...   (Site not responding. Last check: 2007-10-10) Visuals Unlimited Stock Photography: Late telophase stage of mitosis in a spermatogonium. The chromosomes are almost completely surrounded by reforming nuclear envelope and there is a deep cleavage furrow. Late telophase stage of mitosis in a spermatogonium. www.visualsunlimited.com /browse/vu310/vu310081.html   (85 words)

[No title] Sperm development begins with a diploid cell called the spermatogonium located near the outer wall of the seminiferous tubules. One is produced from mitosis of one spermatogonium. Located a little closer to the lumen of the seminiferous tubules. www.lghs.net /teachers/science/shammack/lectures/46/1.html   (422 words)

Meiosis Males do not run out of sperm because mitosis precedes each meiosis. The diagram above shows that a spermatogonium divides by mitosis to produce a primary spermatocytes and a spermatogonium. Human males produce approximately1000 sperm per second (30 billion/year). www.cbsd.org /cb-east/departments/science/kenmoyer/bio100/meiosis.htm   (445 words)

[No title]   (Site not responding. Last check: 2007-10-10) The reason I said that understanding meiosis is a large part of understanding spermatogenesis is that a) most of a sperm cell is nuclear material b) egg production doesn't use meiosis c) sperm cells are diploid d) a spermatogonium divides by meiosis a) primary spermatocyte b) secondary spermatocyte c) spermatogonium d) a normal skin cell www.olemiss.edu /courses/bisc207/test5a.html   (457 words)

Clonal Organization of Proliferating Spermatogonial Stem Cells in Adult Males of Two Species of Non-Human Primates, ...   (Site not responding. Last check: 2007-10-10) spermatogonium; and four generations of B spermatogonia, B an unequal spermatogonial mitosis gives rise to one spermatogonium spermatogonium will result in a different kind of progeny, becoming www.biolreprod.org /cgi/content/full/72/2/293   (4895 words)

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