Ovarian Cycle
This is the day of the cycle on which ovulation typically occurs, marking the boundary between the follicular and luteal phases.
What happens on Day 14?
What is the maximum total number of polar bodies that can be produced from a single primary oocyte across the full course of oogenesis, assuming fertilization occurs ?
3
This structure is made up of tight junctions in between sertoli cells
What is the blood-testis barrier?
A medical condition that occurs when the fertilised egg implants outside the uterus.
What is an ectopic pregnancy?
What is the total follicle count across both ovaries below which menopause typically occurs?
1,000
This phase of the ovarian cycle spans days 1 through 14 and is characterized by follicle growth, ending in ovulation.
What is the follicular phase?
How many oocytes will ever be ovulated across a woman's reproductive lifetime?
400-500
The testes can produce up to this many spermatozoa per day
What is 400 million?
CD9, IZUMO1, JUNO, TMEM95, SOF1, SPACA6, CD81, FIMP
What are hormones necessary for sperm-egg fusion?
A hormone produced by trophoblast cells at the time they invade the endometrium, and which maintains viability of the corpus luteum
What is human chorionic gonadotropin (hCG)?
This structure forms from the remaining granulosa and theca cells of an ovulating follicle, secretes progesterone and estrogen, and degenerates after 10 days if no pregnancy occurs..
What is the corpus luteum?
The ______ triggers the primary oocyte to complete meiosis I, producing a secondary oocyte
LH surge
The basal layer of the seminiferous tubules contains these cell types in spermatogenesis
Which layer of the seminiferous tubules are Type A and B spermatogonia found in?
When sperm binds to zp3, leading to the fusion of acrosomal & plasma membranes, exocytosis of acrosome contents, facilitating sperm & egg binding
What is the acrosome reaction?
Produced by granulosa cells, this hormone acts on the pituitary to selectively suppress FSH release, without significantly affecting LH.
What is inhibin?
Although a whole cohort of antral follicles starts growing together each cycle, typically only this one survives to ovulate, while the rest undergo atresia due to a mid-cycle dip in FSH.
What is the dominant follicle?
Primary oocytes arrest in meiosis I at the ______ stage, remaining suspended there from fetal life until just before ovulation
Prophase 1
This structure in the seminiferous tubules helps propel spermatozoa, provides structural support and has androgen receptors
What is the basal lamina of the seminiferous tubules?
Scarring of uterus (e.g. pelvic inflammatory disease)
Hormonal imbalances (e.g. PCOS, endometriosis)
Non-receptive endometrium (e.g. lack of appropriate receptors, PCOS, endometriosis)
What are some reasons for implantation failure?
This is the cytoplasmic bridge that maintains connections between spermatids
What is the syncytium?
The ovarian cycle is formally defined as the series of changes in the ovary during which these three things occur, in order
What do these three stages put together– the follicle matures, the ovum is shed (ovulation), and the corpus luteum develops– signify?
The secondary oocyte arrests in meiosis II at ______, remaining stalled until fertilization occurs
Metaphase 2
These rod-shaped structures are found in Leydig cells
What are crystals of Reinke?
Multi-nucleated epithelial covering of the highly vascular placental villi. Invades the endometrium to establish nutrient circulation between the embryo and the mother.
What is a synctiotrophoblast?
Oogonia peak at approximately ______ around 20 weeks' gestation, falling to roughly 400,000 by puberty.
6-7 million