Sertoli Cells & Spermatogenesis Flashcards
3 ways Sertoli cells support spermatogenesis?
- Nutritionally
- Hormonally
- Morphological adjustment to support
Which cells create blood-testis barrier?
Sertoli cells
How do Sertoli cells form blood-testis barrier?
Held together by tight junction just above level of spermatogonia
Adluminal compartment means?
Immune-privileged area
What is spermatogenesis?
Entire process of producing spermatozoa
3 phases of spermatogenesis
- Mitosis
- Meiosis
- Metamorphosis
Mitotic spage of spermatogenesis is called?
Spermatocytogenesis
What occurs during spermatocytogenesis?
Spermatogonia divide and give rise to spermatocytes
What occurs during meiosis stage of spermatogenesis?
Spermatocyte becomes haploid spermatid
Between what stages of spermatogenesis does spermatocyte migrate to adluminal compartment?
Between mitosis and meiosis
Mitosis is?
Duplication of genetically identical diploid cells
Meiosis is?
Production of genetically different haploid cells
What process only occurs in sexually reproductive cells?
Meiosis
Which leads to genetic diversity, mitosis or meiosis?
Meiosis
Most primitive cells of spermatogenesis
Spermatogonia
Spermatogonia are involved in which stage of spermatogenesis?
Mitosis
Where are spermatogonia located?
Periphery of seminiferous tubule
3 generations of spermatogonia
- A cells
- I cells
- B cells
What are A cells?
Stem cells that have round nucleus with condensed chromatins
Results of mitotic division of A cell
- 1 cells remains “A” cell
- Other divides and has “I” daughter cells
- “I” cells divde to produce “B” spermatogonia
What cell produces primary spermatocytes?
B spermatogonia
Asymmetric replication only occurs in?
Stem cells
Largest cell in spermatogenesis
Primary spermatocyte
Primary spermatocytes represent the beginning of what stage of spermatogenesis?
Meiosis
Primary spermatocyte has what DNA?
4n
When does “cross-over” occur?
Extended prophase of first meiotic division (primary spermatocyte)
Secondary spermatocyte has what DNA?
2n
What occurs during second meiotic division?
Sister chromatids of secondary spermatocyte pull apart during anaphase to form spermatid
Spermatid DNA
1n
Spermatid appearance
Small round cells → nuclei become flattened and heterochromatic
Which descendant of spermatogonium is not connected by cytoplasmic bridges?
Spermatozoa
Mature spermatozoa are formed during what stage?
Metamorphosis
Mature spermatozoa consists of?
- Head
- Neck
- Tail (middle piece, principal piece, end piece)
What develops during metamorphosis to form mature spermatozoa?
Acrosome, flagellum and nuclear condensation
Anterior pole of spermatozoa nucleus is covered by?
Acrosomal cap
Acrosomal cap contains?
Enzymes (ex: hyaluronidase)
Cryptorchidism occurs most frequently in?
Swine and horses (hereditary)
How does bilateral testical retention result in sterility?
Thermal suppression of spermatogenesis
Why should cryptorchid testicles be removed?
May become neoplastic
Hormone therapy for cryptorchidism
Gonadotropic hormones (FSH, HCG) to prepubertal animals can cause descent of testicles
Definition of metamorphosis
Morphological transformation of spermatozoa (final transition of round cell to final shape)
Do Sertoli cells play a role in metamorphosis?
Yes
