Which ducts move sperm from the testes out of the body?
- Efferent ductules
- Vas deferens
- Ejaculatory duct
Which exocrine glands secrete fluids into the ducts and add to the sperm to make semen?
- Seminal vesicles
- Prostate gland
- Bulbourethral (Cowper's) gland
What type of epithelium makes up the seminiferous tubules?
Simple columnar epithelium of Sertoli cells
Testes are derived from __________.
NOTE: This occurs via the surface gonadal ridge. Testes then descend into the scrotum
The epididymis is derived from the ________.
Primordial germ cells migrate into the testis from the _______.
__________ (warmer/cooler) blood in testicular artery. ________ (warmer/cooler) blood in pampiniform plexus.
NOTE: The pampiniform plexus also plays a role in the temperature regulation of the testes. It acts as a countercurrent heat exchanger, cooling blood in adjacent arteries.
The functional unit of spermatogenesis is the __________.
The strict distinction between the "immortal" germ cell lineages producing gametes and "disposable" somatic cells
Spermatogonia divide via _________ (mitosis/meoisis). Spermatocytes divide via _________ (mitosis/meoisis).
NOTE: Gwem cells remain conencted via intracellular bridges as they complete cell division and migrate upwards
Cell type summary
- The primary spermatocytes undergo Meiosis I and divide into two daughter cells, known as secondary spermatocytes, a process which takes 24 days to complete.
- Each secondary spermatocyte will form two spermatids after Meiosis II.
In spermiogenesis, hapoid spermatids become converted into _________.
Vesicles move from the Golgi stack and adhere to one pole of the nucleus to fuse into a large acrosomal vesicle
NOTE: Acrosome contains hydrolytic enzymes that will later aid in fertilation of an oocyte
What happens to the nucleus of the sperm as it becomes more developed? How is this achieved
The nucleus becomes very small. It is achieved by removing histone proteins from nucleosomes and replacing them with a smaller peptide, protamine
Aside from the removal of histone, how else is change in the nucleus of sperm changed?
The nucleus passes through a narrow perinuclear ring. The perinuclear ring moves along parallel rows o microtubules comprising the "manchette"
_____________ form the center of the flagellum.
Which cell is the main structural cell of the semineferous tubule?
Components of sertoli cells
- Irregular eucromatic nuclei with prominent nucleoli
- Numerous tight junctions
Functions of sertoli cells
- Tight junctions maintain a blood-testis barrier
- Secrete sulfated glycoproteins (clusterin) that transport lipids to germ cells
- Secrete androgen binding protein
- Secrete transferrin
- Secrete inhibin, a TGF-b molecule that inhibits FSH secretion
- Take up glucose from the bloodstream, metabolize it to lactate, and export lactate to germ cells as a nutrient fuel
- Respond to FSH by stimulating the development of germ cells
Structure of Leydig cells
- Mitochondria with tubular cristae
- Abundant sER
- Round, eucromatic nuclei
NOTE: Leydig cells may also possess cytoplasmic crystals of Reinke, composed of an uncharacterized protein aggregate
Function of leydig cells