Spermatogenesis Flashcards
Where is sperm produced?
testis
outside the body cavity to maintain temp and prevent death of sperms due to overheating
15- 25ml volume of sperm
Where is sperm stored?
epididymis
testicular structure and function
testis is 90% seminiferous tubles - and is the site of spermatogenesis
600m seminiferous tubule all coiled togther tightly , lead to rete testis and rete testis leads to the epididymis and the efferent ductules Which lead to the head of the epididymis, tail of epididymis leads to vas deferen that travels around the prostate and semi vesicular fluid and comes down to the urethra
testis function is to form testis and store it
What is the structure of seminiferous epithelium?
The seminiferous tubules is where spermatogenesis takes place
The seminiferous epithelium has sperm cells at different stages of development (spermatogenesis) and contains tight junctions and in between these tight junctions are Sertoli cells which control the movement of substancesfor spermatogenesis
What is the function of sertoli cells?
- sertoli found between germ cells (tight junctions)
-respond to testosterone and regulate spermatogenesis via the formation of tight junction - controls movement of substances into the lumen
-factors produced by sertoli cells is required for development.
What is the function of tight junctions?
-space between sertoli cells
-forms blood testis barrier
-open to allow passage of spermatogonia prior to completion of meiosis
-Divides into basal and adluminal compartments
-protects the spermatogina from immune attack, immune
-allows specific enclosed environment for spermatogenesis which is filled with secretions from sertoli cells
What are the two compartments formed as a result of tight junctions?
Lumenal compartment and adluminal compartment.
What are the 5 stages of spermatogenesis?
- spermatogonia
- primary spermatocyte
- Secondary spermatogenesis
- Spermatids
- spermatozoa
What happens in Spermatogonia stage?
germ cell on basement membrane, capable of mitotic or meiotic division to produce primary spermatocytes or more spermatogonia by mitosis. They are diploid.
What happens in primary spermatocyte stage?
cell committed to differentiative pathway, primary spermatocytes are 46 XY diploid. They move into the adluminal compartment and duplicate their DNA to produce sister chromatid which exchange genetic material and enter meiosis I
What happens in the secondary spermatocytes stage?
have undergone meiosis I to give 23X + 23Y haploid number of chromosomes, arranged as sister chromatids
What happens in the spermatids stage?
meiosis II occurs to give 4 haploid spermatids. Round spermatids to elongated spermatid differentiation.
What happens in the spermatozoa stage?
mature sperm extruded into the lumen.
What are the 3 main stages of spermatogenesis?
- mitotic proliferation of spermatogonia
- meiosis and development of spermatocytes
- Spermatogenesis, elongation, loss of cytoplasm, movement of cellular content
What is the length of a spermatogenesis cycle?
new cycle every 16 days, entire process takes approx 74 days.