Sperm Transport and Capacitation

Vocabulary flashcards covering the processes of spermatogenesis, spermiation, sperm differentiation phases, and transport/capacitation within the female reproductive tract.

Bifid penis

The two-forked anatomical structure of the Virginia opossum's glans penis, which historically led to the folk belief that they mated through the nose.

Spermatogenesis

A hormonally regulated process involving sequential mitotic and meiotic divisions by which the testes produce specialized spermatozoa from spermatogonia.

Spermiation

The continuous release of spermatozoa from the seminiferous epithelium into the lumen of the seminiferous tubule.

Protamines

Small, arginine-rich nuclear proteins that replace histones during spermiogenesis to allow for the condensation of DNA into a stable, compact sperm head.

Golgi phase

The initial phase of spermatid differentiation characterized by the formation of the acrosomic vesicle and the migration of centrioles to the base of the nucleus.

Acrosomic vesicle

A structure formed by fused proacrosomic vesicles that contains a dense acrosomic granule and eventually covers part of the sperm nucleus.

Axoneme

The central portion of the flagellum (sperm tail) which arises from the distal centriole during the Golgi phase.

Acrosomal phase

A phase of spermatid differentiation involving nuclear and cytoplasmic elongation, where the acrosome grows to cover the majority of the anterior nucleus.

Manchette

A system of microtubules that forms in the region of the caudal half of the nucleus and eventually forms the postnuclear cap.

Annulus

The structural juncture that separates the middle piece of the sperm tail from the principal piece.

Maturation phase

The final stage of differentiation where mitochondria form a spiral assembly around the flagellum to define the middle piece.

Acrosome

A membrane-bound lysosome on the anterior portion of the sperm head containing hydrolytic enzymes like acrosin and hyaluronidase required for penetrating the oocyte's layers.

Cranial vagina

The site of semen deposition in species including cow, sheep, rabbit, primates, dog, and cat.

Retrograde loss

A mechanism of sperm loss during immediate transport where spermatozoa are expelled out of the female reproductive tract.

Phagocytosis

A process where neutrophils, sequestered in the mucosa under the influence of estradiol, selectively remove damaged or non-viable sperm and microorganisms.

Privileged pathways

Low-viscosity mucus channels in the cervix (crypts) that allow motile sperm to bypass the tract while filtering out non-motile spermatozoa.

Capacitation

A reversible process occurring in the female tract where seminal plasma coatings and surface molecules are removed to give sperm the competence to bind the zona pellucida.

Hyperactive motility

A specific type of swimming facilitated by epithelium molecules in the oviduct that is thought to assist in sperm-oocyte contact.

Male pronucleus

The structure formed within the oocyte cytoplasm after the fertilizing spermatozoon enters and its nucleus decondenses.

Epididymosomes

Extracellular vesicles that interact with sperm in the epididymis to facilitate surface and membrane changes, such as glycocalyx modification.