Key Terminology Glossary — REP-02 — Notes

Term	Definition
Spermatogenesis	Complete process of sperm production from spermatogonium to spermatozoon (~64 days)
Spermiogenesis	Morphological transformation of spermatid to spermatozoon (no cell division)
Oogenesis	Process of ovum formation; begins in fetal life; one oocyte per cycle after puberty
Acrosome	Lysosome-derived cap on sperm head; contains hydrolytic enzymes for zona pellucida penetration
Acrosomal reaction	Release of acrosomal enzymes upon sperm contact with zona pellucida
Cortical reaction	Oocyte response to sperm entry; cortical granules modify zona pellucida → polyspermy block
Zona pellucida	Glycoprotein matrix (ZP1, ZP2, ZP3) surrounding oocyte; sperm receptor; hardens post-fertilization
Graafian follicle	Mature (tertiary) follicle; large antrum; contains secondary oocyte; ruptures at ovulation
Corpus luteum	Endocrine structure formed from ruptured follicle; secretes progesterone (+ estrogen)
Corpus albicans	Degenerating corpus luteum (scar tissue); forms when no pregnancy
Blastocyst	Hollow ball of cells with trophoblast + ICM + blastocoel; implants in endometrium
Trophoblast	Outer blastocyst cells → placenta; secretes hCG
Inner cell mass (ICM)	Inner embryoblast cells → embryo proper
hCG	Human chorionic gonadotropin; trophoblast-derived; maintains corpus luteum; pregnancy test basis
Polyspermy	Entry of more than one sperm into an egg; prevented by cortical reaction
Parturition	Childbirth; oxytocin-driven positive feedback loop
Luteal-placental shift	~Week 8–10; placenta takes over progesterone from corpus luteum
Implantation	Blastocyst embedding in endometrium; ~day 6–7 post-fertilization
Fimbriae	Finger-like projections of infundibulum; collect ovulated oocyte
Ampulla	Widest fallopian tube region; site of fertilization
Isthmus	Narrow fallopian tube region; connects to uterus
Leydig cells	Interstitial cells; secrete testosterone; respond to LH
Sertoli cells	Sustentacular cells inside seminiferous tubules; nourish sperm; form blood-testis barrier