Spermatogenesis Part 2 Flashcards
What must spherical spermatids do?
- Must condense nuclear DNA (grows tail)
- Form a cell that become motile for ertilization
During the Goligi phase (spermatid) what occurs?
- initial acrosome formation
- Initial tail development, translocation of centrioles
*Proximal ceontriol
*Distal centriol
What is a proximal centriol? What is a Distal centriol?
- Attachment point of tail (flagellum)
- Central portion of tail or axoneme (tail fibres)
What occurs during the cap phase?
- Acrosomic vesicle flattents and “caps” the nucleus
- Primitive tail grows from distal centriole
- Acrosome membrane formed (outer and inner)
- Production of hydrolyic enzymes (Acrosinm hyaluronidase, zona lysin, esterases, acid)
What occurs in Acrosome reaction ?
- Exocytosis during fertilization
- Digest zona pellucida
What occurs in the Acrosomal phase?
- Acrosome covers 2/3 nucleus, nucleus elongates
- Manchette microtubules form: become postnuclear cap
- Neck & annulus formation
What is an Annulus?
Junction between midpiece & principle piece
What occurs in the maturation phase (The final sperm assembly (FSH dependent))?
- Spermatid becomes a spermatozoon
- Mitonchondria surround mid-piece in helical fashion
- Completion of tail
- Spermiation
What does the completion of tail consist of?
- Mid-piece
- Principal piece
- Terminal piece
What is Spermiation?
The release of sperm from sertoli cells into the lumen of the seminiferous tubules
What is necessary to transcript? What is necessary to translate?
- Needs chromosomes
- Needs ribosomes
What can the spermatozoon do?
- Sperm chromatin are compacted and condensed
- DNA is protected by disulfide bonds
- Sperm do not transcribe or translate protein
What does the ultrastructure of sperm consist of?
- Head
- Midpiece
- Principle Piece (tail)
What attaches the head to the tail? What gives the neck flexibility? Metabolic power plant is what piece?
- Capitulum
- Laminated columns
- Mitochondrial helix
How is the arrangement of the principle piece?
- Unique fiber arrangement (9+9+2) contract/release to create movement
* 2 central fivrils through all tail pieces
* 9 double fibrils through mid and principal pieces
* 9 course outer fibers mid piece only
How does the testis produce sperm on a continual basis?
Through the cycle of the seminiferous epithelium
What are the layers of skin of the scrotum?
- Scrotal skin
- Tunica dartos
- Scrotal fascia
- Pariental vaginal tunic
- Visceral vaginal tunic
What is the cycle of seminiferous epithelium (describes process in time)?
Progression of sperm through a series of cellular associations (stages) at one location along a seminiferous tubule
What does the seminiferous epithelium consist of?
- Stage = specific cellular associations
- Stage duration = time for completion of one cell stage
- Cycle = progression through the sequence of all stages (there are 8 stages)
- Cycle duration = time required to complete one cycle
For spermatogenesis how many cell cycles does it need to be completed? How many times does sperm need to repeat this process?
- Takes 8 stages to complete
- Sperm must repeat this process 4.5 times to become mature spermatids
How many generations are in Stage 1? How many are in Stage 4? What is the difference between the 2?
- 4 generations
- 5 generations
- Stage 4 spermatids are more elongated and advanced than those in stage 1
When are elongated spermatids ready for release?
Stage 8
In stage 4 where do the spermaozoan go?
In stage 8 they are ready to release elongated spermatoza into the lumen
Are all zones ready for sperm to be released? If not why?
- No, only certain zones where sperm are ready to be released.
- All other zones are just in the preparatory stage.
