Testis and spermatogenesis Flashcards
Testis anatomy
Tunica vaginalis
- Outer lining, same as peritoneum
Tunic albuginea
- White outer coating adhering to seminiferous tubules
Seminiferous tubules
Efferent ducts
Rete testis
Epididymis
Vas deferens
Compartment of testis
Production of two main products- hormones and spermatozoa
Seminiferous tubules
- Spermatogenesis
Stroma with Leydig cells
- Testosterone production
- Adjacent to seminiferous tubule
- Highly vascularised
Hormone secretion of the testis
Leydig cells make testosterone
- Cholesterol and acetate
4-10mg/ day
In Sertoli cells
- Converts testosterone to dihydrotestosterone
Control of hormone secretion
LH stimulates Leydig cells to secrete testosterone
FSH stimulate Sertoli cells
LH and FSH secreted from pituitary
- Increased secretion at puberty
Seminiferous tubules
- Structure
- Function
Sertoli cells forms physiological barrier on the outside–> basement and adluminal compartments
- Gap junctions
- Tight junctions
Myoid cells
- Outer layer, muscular fibres
Spermatogenesis
- Part one
Mitosis
- Prospermatogonia reactivated at puberty
- Mitosis in basal compartment - Spermatogonia divide to form clone cells
- After final division, it forms primary spermatocyte
- Nuclei are divided but not the cytoplasm
Spermatogenesis
- Part two
Primary spermatocyte enter meiosis
- Homologous chromosomes to opposite ends of the cell
- Divide to diploid cells: secondary spermatocyte
Another division
- Spermatid–> haploid
Spermatogenesis
- Part three
Packaging of spermatid
- Tail for propulsion
- Mid-piece with mitochondria
- Nucleus with packaged chromosome
- Cap region, contains receptors to bind to oocyte
- Acrosome allows oocyte penetration
Unwanted material is phagocytosed by Sertoli cells
Regulation of spermatogenesis
After spermatogenesis is originated in a location from a spermatogonium, it is not started for 16 more days.
Spermatogonium are activated are different times in different locations
- Loci outside the tubule stimulates spermatogenesis
Spermatogenic wave
Seminiferous tubules organised along the length of the tubule
- Mature along the length of the tubule
Final stages of maturation for spermatozoa
- Wash into rete then into efferent ducts
- Can twitch in rete - Concentrated in epididymis
- Can swim in the cauda - Into vas deferens, released into semen
Components of semen
Spermatozoa
Epithelial cells from tract lining
Spermatogenic cells (spermatogonia)
Leucocytes
Secretions from bulbourethral and seminal glands
- Fructose, soerbitol
- Buffer
- Antioxidants
Endocervix function
Secretes mucus
- Interferes with sperm movement
Receptive to sperm in ovulation
Prevents phagocytosis of sperm
Supplement of energy requirements for sperm
Sperm selection for differential motility and morphology
Short term reservoir in crypts
Capacitation
Capacitation of sperm
Glycoprotein coating sperm are stripped off.
- Changes the motility of spermatozoa from circular to whiplash
- Makes sperm more responsive to signals from oocyte
Assessing cervical mucus
Spinnbarkeit
- The elasticity
Ferning
Viscosity
