repro 2.1- control of reproductive processes.

Question 1

What does sucessful fertilisation depend on?

Answer 1

• correct number of gametes produced at the right time
• effective transport of sperm from male to female
• successful fertilisation
• support of conceptus, embryo and feotus
• support of neonate

Question 2

where does the anterior pituatory gland originate from?

Answer 2

an outpouching of the epithleial tissue from the roof of the mouth,
Known as Rathke’s pouch
This then migrates to the adult location

Question 3

What are the main secretions of the anterior pituatary gland?

Answer 3

trophic hormones.

Question 4

Where does the posterior pituitary gland originate from?

Answer 4

a growth from the brain, it is therefore made of nervous tissue.

Question 5

What tissue is the anterior pituitary formed from?

Answer 5

endocrine

Question 6

what 2 types of hormones are produced in the anterior pituitary gland?

Answer 6

glycoprotein hormones

polypeptide hormones

Question 7

What glycopeptide hormones are produced in the anterior pituitary?

Answer 7

FSH, LH

TSH

Question 8

What polypeptide hormones are produced in the anterior pituitary?

Answer 8

growth hormone
prolactin
ACTH

Question 9

What cell types are found in the anterior pituitary?

Answer 9

gonadotrophs
thyrotrophs
somatostrophs
corticotrophs
lactotrophs

Question 10

How is the anterior pituitary secretions controlled?

Answer 10

by control of the hypothalamus.

releasing hormones travel in the hypophysealcirculation as neurosecretions, and act on the anterior pituitary.

Question 11

What releasing hormone controls the reproductive hormones?

Answer 11

FSH and LH crelease is controlled by gonadotrophin releasing homrone (GRH)

Question 12

what’s characteristic about the GRH release?

Answer 12

it’s pulsatile

Question 13

how can you increase the amounts of LH and FSH released?

Answer 13

increase the frequency or magnitude of pulses.

Question 14

What are the broad functions of LH and FSH?

Answer 14

act on the gonads to stimulate gamete production, and secretion of gonadal steroids.

Question 15

What’s the effect of moderate oestrogen levels in a female?

Answer 15

reduction in GnRH levels, normal negative feedback.

Question 16

What’s the effect of high levels of oestrogen alone?

Answer 16

positive feedback, increases the amount of GnRH released, and therefore is teh basis behind the LH surge.

Question 17

what’s the effects of progesterone on GnRH release?

Answer 17

Only takes effect in the presence of oestrogen:

• moderate oestrogen- increases the inhibitory effect
• high levels of oestrogen, prevents positive feedback, therefore LH surge.

Question 18

with regards to the pulsatile nature of GnRH release, what’s the effects of:

a) oestrogen
b) progesterone?

Answer 18

a) oestrogen increases the amount of GnRH per pulse.

b) progesterone affects the frequency of the pulses.

Question 19

What does inhibin do?

Answer 19

Inhibits the release of FSH

Question 20

Where is inhibin released from?

Answer 20

granulosa cells of developping follicles in a woman.

sertoli cells in a man.

Question 21

in the male, what are teh effects of;
LH
FSH

Answer 21

LH binds to Leydig cells, and promotes testosterone secretion
FSH binds to sertolli cells which stimulates inhibin secretion.

Question 22

in the female, what are the effects of
LH
FSH

Answer 22

LH binds to the theca interna cells, leading to production of androgens, which are converted to oestrogen by the granulosa cells.
FSH binds to the granulosa cells, which produce oestrogen and inhibin.

Question 23

in the follicluar phase, what are the actions of oestrogen?

Answer 23

• thin, alkaline cervical fluid
• thickening of the endometrium
• thickening and motility of the myometrium
• increased motility of fimbriae

Question 24

In the luteal phase, what are the actions of progesterone?

Answer 24

• further thickening of the endometrium and myometrium
• thick, acidic cervical fluid
• increased body temperature

Question 25

If fertilisation occurs, what happens to the corpus leuteum?

Answer 25

It is maintained by human chorionic gonadotropin, which is released from the syncitiotrophoblast of the embryo.