pack Flashcards
(16 cards)
What are the 4 phases of spermatogenesis?
Spermatogonia produce sperm.
Mitosis: Spermatogonia form spermatocytes [2n].
Meiosis: Spermatocytes form spermatids [n].
Spermiogenesis: Spermatids change into spermatozoa (not spermatocytes).
Spermiation: Sperm are released from Sertoli cells into the seminiferous tubule lumen, making their way to the epididymis.
What two hormones regluate spermatogenesis?
Regulated by hormones - FSH and Testosterone.
how are primary spermatocytes formed?
Spermatogonia divide several times and differentiate into primary spermatocytes
What happens during the first meiotic division of primary spermatocytes?
The first meiotic division produces secondary spermatocytes.
What is produced from the second meiotic division?
The second meiotic division results in spermatids, which are haploid (n) cells.
What happens during spermiogenesis?
- Spermiogenesis → change of round spermatids into spermatozoa. Involves the following events:
spermatid condensation of nuclear material,
formation of the acrosome,
repositioning of the spermatid to allow formation and elongation of tail structures,
mitochondrial spiral formation, and
removal of extraneous cytoplasm.
What are the 4 structural components of the spermatozoa and what does each component contain?
Head: nucleus of the sperm which includes the genetic information.
Acrosome: has enzymes - hyaluronidase and acrosin [a protease]. They digest the cumulus cells and enter zona pellucida of oocyte. Enzymes are released when the sperm contacts the ovum.
Tail: Sperm mobility
Mid-piece: spiral mitochondria provides energy for flagella motility.
What are the two enzymes in the acrosome?
hyaluronidase and acrosin
What are the roles of sertoli cells in spermatogenesis?
What is decapacitation?
Decapacitation regulates the fertilizing ability of spermatozoa by controlling surface-associated proteins.
(Basically makes it inactive)
How is decapacitation maintained?
It depends on sperm surface-associated proteins that are controlled by the interaction between cholesterol, phospholipidsandfibronectin-like substances.
These substances are delivered via small vesicles inseminal vesicles and released in secretions from theepididymisand accessory glands.
Where does capicatation occur?
Capacitation occurs in the oviduct
What is capicatation
basically activation of sperm so it can fertilize the egg
What changes occur for capcitation to take place?
- Change in membrane fluidity due to the removal of cholesterol from the sperm membrane
- The removal of glycoproteins from the membrane that blocks sperm binding to the egg.
- A change in membrane potential that permit Ca2+ to enter the sperm and facilitate the acrosome reaction.
- Phosphorylation of numerous proteins
What should the post acrosomal region not contain?
the post-acrosomal region should not contain any vacuoles
What is globozoospermia?
a condition where sperm cells are abnormally round (globular) and have defects in their structure
