Menstrual Cycle

Question 1

Where does the ovarian artery arise from and at which level?

Answer 1

Abdominal aorta at the level of the renal arteries

Question 2

course of the ovarian artery

Answer 2

Passes laterally, anterior to the ureter (water under the bridge) and inferiorly into the pelvis
supplies the ovary and then continues towards the uterus

Question 3

where do the left and right ovarian veins drain into?

Answer 3

right - IVC

left - left renal vein

Question 4

which other arteries does the ovarian artery anastomose with?

Answer 4

uterine and vaginal arteries

Question 5

what is the importance of the anastomoses of the ovarian artery?

Answer 5

allows rapid transfer of hormones from ovary to uterus and vagina - enables co-ordination of changes in the menstrual cycle

Question 6

what are the different cell types in the embryonic cortex

Answer 6

epithelial cells (lining)
stromal cells (spindle shaped, display whorling patterns)
PCGs, oogonia

Question 7

how are primordial follicles formed?

Answer 7

primary oocyte (arrested in diplotene stage of meiosis I) + single layer of granulosal cells (flattened epithelial cells, mesenchymal)

Question 8

what hormone does follicular development and maturation depend on?

Answer 8

gonadotrophin

Question 9

how is the ovarian cycle regulated?

Answer 9

hypothalamus releases gonadotrophin releasing hormone (GnRH) which stimulates the anterior pituitary gland to release gonadotrophins which are involved in the synthesis of LH and FSH

Question 10

what is the role of FSH?

Answer 10

follicle growth, proliferation of granulosa cells, estradiol production

Question 11

what is the role of LH?

Answer 11

ovulation, follicular lutenisation and progesterone production

Question 12

what happens at puberty to the primordial follicles?

Answer 12

FSH stimulates development of 30-40 primordial follicles to primary follicles

Question 13

how do primordial follicles convert to primary follicles?

Answer 13

• enlargement of the oocyte
• proliferation and increase in granulosa cells (become more cuboidal in shape)
• multilayering of granulosa cells
• formation of zona pellucida (glycoprotein barrier) between oocyte and cells

Question 14

what is the function of the zona pellucida in the primary follicle?

Answer 14

ZP proteins are important for protection and avoidance of polyspermy

Question 15

What is the function of gap junctions in the primary follicle and where are they located?

Answer 15

• between the oocyte and granulosa cells
• allow transfer of metabolites and regulatory substances between the two cell types
• cAMP from GC maintains meiotic arrest of oocyte

Question 16

What do thecal cells produce?

Answer 16

androgens

Question 17

what do thecal cells and granulosa cells together produce?

Answer 17

oestrogen

Question 18

which cells produce oestrogen?

Answer 18

thecal and granulosa cells