Puberty, Secondary Sexual Characteristics, Menstrual Cycle, Contraception

Question 0

Day 0-14

Answer 0

New follicle to graafican follicle, proliferation phase
Surge in GnrH from hypothalamus
Simulates FSH and LH from ant pit.
FSH causes follicle to produce oestradiol by granulated cells
Oestradiol has negative feedback effect on ant pit.
LH acts on thecal cells to produce androgens
Oestradiol levels continue to increase despite negative feedback as it also causes proliferation of granulosal cells

Question 1

Hormones involved in the menstrual cycle

Answer 1

Gonadotropin releasing hormone

Gonadotropin releasing hormone, hypothalamus
Follicle stimulating, anterior pituitary
Lutenizing, anterior pituitary
Oestradiol, ovary
Progesterone, ovary

Question 2

Oestradiol synthesis

Answer 2

Cholesterol 
Pregenolone
Progesterone
Androstenedione passes from thecal to granulosal
Testosterone and oestrone
Oestradiol

Question 3

Ovulation

Answer 3

At mid cycle, negative feed back of oestradiol becomes positive allowing a short surge of LH to be release.
High oestradiol together with FSH cause the effect of LH to change and instead cause cholesterol to be converted to progesterone in granulosal cells.
LH receptors appear on granulosal cells instead of FSH
Increased progesterone synthesis
Release of oocyte
Recruitment of 5-9 new follicles

Question 4

Days 14-28

Answer 4

Corpus leuteum formed from collapsed follicle-> maintained by LH, secretes progesterone (maintains endometrium)
Progesterone-> negative feedback to hypothalamus-> decrease GnRH production-> low FSH and LH-> no new follicles developed

Question 5

Menstruation

Answer 5

Corpus leuteum degenerates->decrease progesterone and oestradiol->increase in LH and FSH-> new follicles mature->onset of menstruation.

Question 6

Contraceptives

Answer 6

Progesterone-> suppression of ovulation, decrease GnRH soon we follicles develop
Combined->oestrogen as well

Question 7

Onset and cessation for menstural cycle

Answer 7

Onset:
2-4 years prior->increase in sex hormones from gonads and adrenal glands
Females-> activation of GnRH pulses caused by maturation of CNS
Cessation: pregnancy->high progesterone
Menopause->ovaries loose ability to respond to FSH and LH

Question 8

Body changes in puberty

Answer 8

Female:
Ovarian oestrogens regulate breast growth and genitalia
Androgens control growth of pubic and axillary hair
Male:
Increase in steroid hormones from gonads and adrenal glands
Testicular androgens control development of genitalia,body hair, larynx enlargement and laryngeal muscle growth