male reproductive sys lecture (M1B1) Flashcards
(20 cards)
Spermatogenesis begins at puberty with proliferation of a small basal round progenitor cells called?
spermatogonia
spermatogonia can be divided (mitotically) into three groups
according to their nuclear appearance:
- Type A-dark (Ad) cells,
- Type A-pale (Ap) cells,
- Type B cells.
Type Ad spermatogonia are?
stem cells of the system, their mitotic division form clusters of daughter cells linked to each other by cytoplasmic bridges.
type Ap spermatogonia mature into?
type B cells
(which divide mitotically to produce further type B cells; these cells then mature in a cluster to produce primary spermatocytes)
Primary spermatocyte formation marks the end of?
spermatocytogenesis
Primary spermatocytes pass through a long prophase lasting about 22 days, during which changing patterns of nuclear chromatin enable what to be identified?
preleptotene, leptotene, zygotene, pachytene and diplotene stages
The first meiotic division occurs after the?
late pachytene/diplotene stages
The stem cells produced by mitotic divisions of spermatogonia remain as separate cells. However, all subsequent divisions of the daughter cells have incomplete cytokinesis after telophase and the cells remain attached to one another by intercellular bridges of cytoplasm. The germ cells finally become separated from one another during differentiation.
…
Significant of cytoplasmic bridge?
- Allow free cytoplasmic communication among the cells during their remaining mitotic and meiotic divisions.
- Helping to coordinate their divisions and differentiation
- Allow the haploid cells to be supplied with products of the complete diploid genome, including proteins and RNA encoded by genes on the X or Y chromosome missing in their haploid nuclei.
the process by which haploid spermatids are transformed into
spermatozoa is called?
Spermiogenesis
Spermiogenesis can be divided into four phases which are? SEE SLIDES
- The Golgi phase
- The cap phase
- The acrosome phase
- The maturation phase.
The Golgi phase ?
in order for the sperm to enter the egg, it has to break the barrier of the egg, in order for that to happen it needs enzymes to break it down, that is acrosin (hydrolytic) which acrosomal cap. the centrioles in the sperm migrates to the bottom of the acrosomal cap.
The cap phase?
acrosomal cap spreads over about half of the condensing nucleus.
the acrosome phase?
nuclei becomes elongated n highly condensed, ATP coming from the mitochondria is the reason the Flagellum (tail) moves
the maturation phase?
is like a cleaning phase where the cytoplasm and intercellular bridges are un needed residuals (left overs) so they are lost. it’s mature but NOT functional or mobile
what are sertoli cells?
- tall columnar cells with active nucleus
- cell membrane is irregular, cytoplasm extension to make contact to neighboring sertoli cells to form meshwork of cytoplasm
- barrier is formed by tight junctions, adherens junctions and gap junctions between the Sertoli cells, which are sustentacular cells (supporting cells) of the seminiferous tubules
Functions of Sertoli cells?
1) transport of waste materials from spermiogenesis to the blood and lymph vascular systems surrounding the seminiferous tubules.
2) Testicular barrier
3) Phagocytose any residual cytoplasm shed by maturing spermatids during spermiogenesis.
4) Secretory functions that vary with sexual maturity
Sertoli cells are the epithelial supporting cells of the seminiferous tubules. They are derived from the epithelial sex cords of the developing gonads. … The blood-testis barrier formed by the Sertoli cells effectively isolates the developing spermatogonia, spermatocytes, spermatids and mature spermatozoa from blood.
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what is Oligospermia?
Decreased semen quality, major cause of infertility
what’s Orchitis?
Acute or chronic inflammation of the testis, frequently involves the ducts connecting this organ to the epididymis.
