Male Reproductive System Flashcards
Seminiferous tubules are enclosed by….., rich in….., their function is……
Myoid cells
rER
Have a role in collagen synthesis & have rhythmic contractions that aid in movement of spermatozoa along length of tubule
Spermatogenic cells are arranged in …..layers, they are……
4-8
Spermatogonia, 1ry spermatocytes, 2ry spermatocytes, spermatids
Mention the result of divison of each of the following:
1. Dark type A spermatogonia
2. Pale type A spermatognoia
3. Type B spermatogonia
- Dark type A & pale type A
- Pale type A & type B
- Primary spermaticytes
Dark type A act as……but pale act as……
Reserve stem cells
Undifferentiated stem cells
Type B spermatogonia divide by……under effect of…..
Mitosis
FSH
The largest spermatogenic cells are……, they are most common in section because…….
1ry spermatocyte
It remains in prophase I of meiosis for about 22 days
Describe genetic composition of:
1. Spermatogonia
2. 1ry spermatocytes
3. 2ry spermatocytes
4. Spermatids
- 46 S-chromosones (2N)
- 46 D-chromosomes (4N)
- 23 D-chromosomes (2N)
- 23 S-chromosomes (1N)
Describe course of the following:
1. 1ry spermatocytes
2. 2ry spermatocytes
3. Spermatids
- Enter S phase of cell cycle where DNA is duplicated & enter first meiotic divisoj to give 2ry spermatocytes
- Enter 2nd meiotic division to give 2 spematids without S phase
- Transforms into spermatzoon by spermiogenesis
Spermatogenesis consists of……&….
Spermatocytogenesis
Spermiogenesis
List stages (general) of spermatocytogensis +brief note
- Proliferation: spermatogonia divide by mitosis
- Growth of daughter type B spermatogonia to give 1ry spermatocytes
- Maturation includes 1st meiotic divison & 2nd meiotic divison
After meiosis, Daughter cells are attached to each other by…….., whose function is…….
Intercellulr bridges
Allows genetic cross talk between haploid cells and synchronous development of each clone from type A spermatogonia
Define & List stages of spermiogenesis
It is transformation of spermatids into spermatozoa without divison
Golgi, cap, acrosomal phases
Mention events that occur in Golgi phase of spermiogenesis
- Golgi complex becomes near the nucleus, small PAS +ve granules appear in golgi complex called proacrosomal granules
- Fuse together & are enclosed with a membrane to form acrosomal vesicle adjacent to nuclear membrane
- At the same time, the 2 centrioles migrate to opposite pole of nucleus, the distal one acts as basal body organizing axoneme of flagellum
Mention events that occur in Cap phase of spermiogenesis
- Acrosomal vesicle spread over ant half of nucleus forming cap
- Nucleus becomes condensed & the nuclear membrane thickens & loses its pores
- Acrosome contains hydrolytics (phosphatase, protease called acrosin) that help penetration of zona radiata & pellucida of 2ry oocyte
Mention events that occur in acrosomal phase of spermiogenesis
- Nucleus forms head of sperm
- Nucleus & acrosome move to ant plasma membrane & the cytoplasm is displaced posteriorly
- Cytoplasmic microtubules become organized into cylindrical sheath, Manchette, where extends from post part of acrosomal cap towards posterior pole of spermatid
- Distal centriole moves to post surface of nucleus & forms flagellum
- In neck region, nine coarse fibers produced from centriole surrounding the microtubules of the axoneme
- Mitochondria are arranged around the proximal part of the flagellum to form the thickened middle piece of the sperm, which stop at annulus
- Plasma membrane moves posteriorly to cover the flagellum
- Movement of the flagellum is due to interaction among microtubules ATP & dynein which is a protein with ATPase activity.
Mention events that occur in maturation phase of spermiogenesis
The excess cytoplasm is shed off as residual bodies which are phagocytosed by Sertoli cells, intercellular bridges are lost, spermatozoa are released into lumen of seminiferous tubules & remain immotile until they leave the epididymis.
Neck of sperm contains……….
Centriole & a connecting piece which forms the 9 coarse fibers that will surround the axoneme
Tail of sperm is composed of……..
Middle piece, principle piece, end piece
Mention components of middle piece
- Axoneme: 2 central singlets, 9 peripheral doublets
- Nine coarse longitudinal fibers that arise from connecting piece of the neck
- Tightly packed elongated mitochondria forming mitochondrial sheath to provide the necessary energy for flagellat motility
- Plasma membrane
Immotile cilia is due to………
Lack of dynein or other proteins required for motility of cilia
Apical cell membrane of Sertoli cells shows……..
Infoldings that contain head of the sperms (LM)
Pockets to embrace the spermatogenic cells (EM)
Describe connections of Sertoli cells & their functiom
- Tight junctions, divide seminiferous tubule into basal (spermatogonia) & adluminal (spermatocytes, spermatids, sperms) compartments
- Gap junctions, provide ionic & chemical transport between cells