Session 2 - Hormone Stuff

Question 1

What does LH act on in the male and what does it produce?

Answer 1

Leydig cells to promote the secretion of testosterone.

Question 2

What are the actions of LH enhanced by in the male?

Answer 2

Prolactin

Question 3

What are the actions of FSH in the male?

Answer 3

Acts on sertoli cells to facillitate spermatogenesis and produce inhibin

Question 4

What are the three phases of the menstrual cycle?

Answer 4

Antral
Pre-ovulatory
Luteal

Question 5

What happens in the antral phase?

Answer 5

o	LH binds to Theca Interna cells
	Produce Androgens
	Primarily Androstenedione
o	FSH binds to Granulosa cells
	Produce enzymes 
	Androgens  Oestrogen

o As the follicle grows, more oestrogen is produced for a given amount of LH and FSH

Question 6

What happens in the pre-ovulatory phase?

Answer 6

o Follicle has grown, and is producing a high amount of Oestrogen
o LH receptors develop in outer layers of Granulosa Cells
o [High] Oestrogen positively feeds back
o LH Surge produced
 Stimulates ovulation
 Follicle size increases, collagenase activity
 FSH still being inhibited by Inhibin

Question 7

What happens in the luteal phase?

Answer 7

o Remains of follicle reorganise into Corpus Luteum
o LH stimulates the Corpus Luteum
o Produces Oestrogen and Progesterone
 Progesterone prevents +’ve feedback
 Enhances –‘ve feedback
 Prevents new follicles from developing ( FSH)

o As the Corpus Luteum grows, more steroids are produced for a given LH level

Question 8

What are the two types of action of gonadal steroids?

Answer 8

Determinative and regulatory

Question 9

List five determinative actions of testosterone

Answer 9

o	Increase size and mass of muscles, vocal cords, bones
o	Deepening of the voice
o	Facial and body hair
o	Increased stature
o	Growth of the penis

Question 10

List three regulatory actions of testosterone

Answer 10

o Maintenance of the male internal genitalia
 Prostate, seminal vesicles, vas deferens, epididymis
o Metabolic (Anabolic) action
o Behavioural Effects
 Aggression
 Sexual activity

Question 11

List seven actions of oestrogen

Answer 11

o	Fallopian tube function
o	Thickening of endometrium
o	Growth and motility of myometrium
o	Thin alkaline cervical mucus
o	Vaginal changes
o	Changes in skin, hair, metabolism
o	Calcium metabolism

Question 12

Give 7 actions of progesterone on oestrogen primed cells

Answer 12

o Further thickening of endometrium into secretory form
o Thickening of myometrium, but reduction of motility
o Thick, acid, cervical mucus
o Changes in mammary tissue
o Increased body temperature
o Metabolic (mild Catabolic) changes
o Electrolyte changes

Question 13

What are the 5 anatomical parts of the female reproductive system which are changed during the menstrual system

Answer 13

Fallopian tube
Myometrium
Endometrium
Cervical mucus
Vaginal epithelium

Question 14

What happens to the female reproductive tract during the follicular phase?

Answer 14

Steadily rising titres of oestrogen cause
o	Fallopian Tube
Increase Secretion, motility, cilia
o	Myometrium
Increase Growth, motility
o	Endometrium
	 Thickness, glandular invaginations
Secrete a watery fluid, conductive to sperm
o	 Cervical Mucus
	Thin, alkaline, conductive to sperm
o	Vaginal Epithelium
	 Mitosis

Question 15

What happens to the female reproductive system in the luteal phase?

Answer 15

Action of Progesterone on Oestrogen-Primed Cells
o Fallopian Tube
• Decrease Motility, secretion, cilia
o Myometrium
 Further thickening, decreased Motility
o Endometrium
 Further thickening, decreased secretion
 Development of Spiral Arteries
o Cervical Mucus
 Thickening, acidification. Inhibits sperm transport
o Mildly Catabolic
o Elevates basal body temperature
o Promotes change in Na+ and H2O excretion
 With Oestrogen leads to net Na+ and H2O retention

Question 16

What does the sudden fall in progesterone and oestrogen levels cause?

Answer 16

o The elaborate secretary epithelium of the endometrium collapses
o Apoptotic cell death
o Dead tissue shed as menstrual bleed.
o Spiral arteries contract to reduce bleeding.

Question 17

How is testosterone release regulated by feedback control?

Answer 17

If Testosterone levels rise:
o	GnRH secretion is inhibited.
	Reduced LH and FSH
o	LH and FSH are reduced further by testosterone reducing sensitivity of Gonadotrophs to GnRH
So Testosterone levels fall back

If Spermatogenesis proceeds too rapidly, Inhibin levels rise
o Inhibin reduces secretion of FSH by acting on Gonadotrophs

Question 18

Describe the pattern of secretion of gonadotrophins and gonadal steroids at beginning of cycle

Answer 18

o Oestrogen, Progesterone, Inhibin levels low
o GnRH secretion is released from inhibition
o LH and FSH rise, FSH more as low Inhibin levels release FSH from selective inhibition at the pituitary

Question 19

What causes follicles to grow?

Answer 19

FSH, followed by LH causes Follicles to Grow

Question 20

How happens if conception occurs?

Answer 20

o The implanted embryo develops a placenta, which secretes Human Chorionic Gonadotrophin (hCG)
o hCG prevents the regression of the Corpus Luteum
o Continues to secrete Oestrogen and Progesterone
o Supports early weeks of pregnancy (Until about 12-14 weeks)
o Maintains suppression of the ovarian cycle