Menstral Cycle

Question 1

Describe the Luteal Phase

• Temperature
• ovulation
• corpus luteum
• estrogen/progesterone

Answer 1

Starts with ovulation

Decrease in body temperature then and increase of 0.5 - 1 degree F around ovulation time

Corpus luteum

• formed from follicle cells
• remains in the ovary after ovulation
• secretes progesterone and estrogen during last 14 days of cycle
• degenerates if ovum not fertilized = progesterone and estrogen levels decrease

Decrease in estrogen and progesterone stimulates anterior pituitary to secrete more FSH and LH = initiating new reproductive cycle

Question 2

Describe the menstrual phase

• endometrium

Answer 2

• 4-6 days of bleeding
• breakdown of endometrium due to decreased levels of estrogen and progesterone
• FSH levels increase = enabling new cycle to start

Question 3

Describe the proliferative phase

Answer 3

Lasts ~ 9 days
Estrogen = stimulates proliferation/growth of endometrium
Estrogen levels increase = suppressing secretion of FSH and increasing secretion of LH

-LH = stimulates ovulation/ development of corpus luteum
Btwn days 12-16 = ovulation
Estrogen levels high/ progesterone levels low

Question 4

Describe secretory phase

Answer 4

Last ~12 days/ follows ovulation
Initiated by increase in LH level
Graafian follicle = replaced by corpus luteum
Corpus luteum secretes progesterone/estrogen
Progesterone prepares endometrium for pregnancy if fertilized ovum is implanted

Question 5

Describe the preovulatory phase

• GhR
• FSH
• LH

Answer 5

Hypothalamus releases gonadotropin-releasing hormone through anterior pituitary gland

Anterior lobe of pituitary gland secretes follicle-stimulating hormone = growth of follicles

Follicle produces estrogen = stimulates increased secretion of luteinizing hormone by anterior lobe of pituitary gland

Follicle ruptures = releasing ovum into peritoneal cavity