Oocytes and sperm

Question 1

What happens before birth with eggs?

Answer 1

start as oognoium which undergoes mitosis to form a primary oocyte which starts meoissi but arrests in its progress

Question 2

What phase does the primary oocyte arrest in?

Answer 2

prophase 1

Question 3

What happens during puberty to the egg?

Answer 3

meiosis occurs giving rise to a secondary oocyte and a polar body

Question 4

What phase does the secondary oocyte arrest in?

Answer 4

metaphase 2

Question 5

How is a polar body formed?

Answer 5

when the egg divides, it does so unequally, with the majority of cell material and organelles going into one cell (secondary oocyte) and the other set of chromosomes and a small amount of cytoplams forming a polar body

Question 6

When would the secondary oocyte continue through meiosis II?

Answer 6

if it is fertilised in the uterus

Question 7

Where does spermatogenesis occur?

Answer 7

in the wall of the seminiferous tubules

Question 8

What are the sperm stem cells called?

Answer 8

spermatognoia

Question 9

What happens when the spermatogonia undergoes mitosis?

Answer 9

one offsrping goes on to differentiate into a sperm cell whilst the other gives rise to the next generation of sperm

Question 10

What is the cell formed at the end of meiosis called?

Answer 10

spermatid

Question 11

When is a second polar body produced?

Answer 11

when the oocyte has completed meiosis

Question 12

What are the two phases of the menstrual cycle?

Answer 12

follicular and luteal

Question 13

What happens during the luteal phase?

Answer 13

development of the corpus luteum; induces preparation of reproductive tract for pregnancy

Question 14

Where is gonadotrophin releasing hormone synthesised?

Answer 14

by neurons in the hypothalamus

Question 15

Which hormones does GnRH stimulate the release of?

Answer 15

FSH and LH

Question 16

What are the functions of FSH?

Answer 16

follicular development and thickens endometrium

Question 17

What are the functions of LH?

Answer 17

peak stimulates ovulation; stimualtes corpus luteum development; thickens endometrium

Question 18

Where is oestrogen secreted?

Answer 18

primarily by the ovaries, byb adrenal cortex and by placenta in pregnancy

Question 19

What are the functions of oestrogen?

Answer 19

stimualtes thickening of endometrium; reponsible for fertile cervical mucus; maturations of ovarian follicles; mildly accelerates sodium and water reaborption by kidney tubules; increase water content of the uterus

Question 20

What happens when there is a high concentraion of oestrogen?

Answer 20

inhibits secretion of FSH and PRL; stimualtes ecretion of LH

Question 21

What happens when there is a low conc. of oestrogen?

Answer 21

stimulates secretion of PRL

Question 22

What are the functions of progesterone?

Answer 22

inhibits secreiont of LH; increases basal body temp; relaxes smooth muscles; infertile mucus; maintains thickness of endometrium and pregnancy

Question 23

Where is progesterone produces?

Answer 23

by corpus luteum and placenta

Question 24

What hormone stimualtes follicular growth?

Answer 24

FSH

Question 25

What hormone is produced by the developing follicle?

Answer 25

oestrogen

Question 26

What does the increase in serum oestrogen do?

Answer 26

suppresses secretion of FSH and increases secretion of LH

Question 27

What is the function of the progesterone produced by the corpus luteum?

Answer 27

to thicken endometrium to prepare for implantation

Question 28

What happens to the corpus luteum if fertilisation does not occur?

Answer 28

corpus luteum begins to regress and production of progesterone and oestrogen decreases

Question 29

What happens during the menstrual phase?

Answer 29

corpus luteum degenerates; cessation of progesterone and oestrogen produced by corpus luteum which causes the endometrium to degenerate and menstruation to occur

Question 30

What does in the drop in serum oestrogen adn progesterone cause?

Answer 30

stimulates production of FSH and the beginning of a new cycle

Question 31

How long after LH surge does ovulation occur?

Answer 31

36 hours

Question 32

What is the route of sperm?

Answer 32

testes- epipdidymis- vas deferens- ejaculatory duct- urethra

Question 33

What cells does LH act on in the male?

Answer 33

Leydig cells

Question 34

What is the function of LEydig cells?

Answer 34

regulate testosterone secretion

Question 35

What cells does FSH act on?

Answer 35

Sertoli cells

Question 36

What is the function of sertoli cells?

Answer 36

to enhance spermatogenesis- essential for spermatid remodelling

Question 37

How does the negative feedback of testosterone work?

Answer 37

suppresses GnRH bursts; reduces sensitivity of LH-secreting cells to GnRH; LH inhibited more than FSH

Question 38

What hormone do the sertoli cells produce which has negative feedback?

Answer 38

inhibin

Question 39

How long does it take to produce a sperm?

Answer 39

around 72 days

Question 40

What is the name of the tail on a sperm?

Answer 40

cilium