Reproductive physiology of the female

Question 1

what is the name of the male and female gametes?

Answer 1

• Male gametes: Spermatozoa (sperm) produced by the testes
• Female gametes: Ova (eggs) produced by the ovaries

Question 2

how many chromosomes do the male and female gametes have?

Answer 2

• Male & female gametes are haploid (23 unpaired chromosomes)
• At fertilization, ovum + sperm = zygote (diploid- 23 pairs of chromosomes = 46 unpaired chromosomes)

Question 3

what is an ovarian follicle?

Answer 3

Ovarian follicle- the functional unit of the ovary

Question 4

functions of an ovarian follicle

Answer 4

Functions: Gametogenic and endocrine

Question 5

when is the Development of the oocyte and follicle stimulated?

Answer 5

Development of the oocyte and follicle is stimulated at puberty

Question 6

The life history of a follicle:

Answer 6

1. Primordial follicle
2. Preantral (primary and secondary) follicle
3. Antral (tertiary) follicle
4. Dominant (preovulatory, graafian) follicle
5. Corpus luteum (or corpus albicans)
6. Atretic follicles

Question 7

In the mature antral follicle, oocyte is
surrounded by what

Answer 7

granulosa cells (cumulus cells are a specific type of granulosa cell that surround the oocyte)

Question 8

in the life stages of a follicle, the stages after the preantral stage are hormone dependent, what about it?

Answer 8

• Preantral follicle&raquo_space; maturation&raquo_space; ovulation
• Many primordial follicles begin the
  maturation process but not all can go to the
  next stage.
• The next stages of maturation are hormone-dependent and thus preantral follicles with no hormone
  receptors die (atresia).

Question 9

what is a graafian follicle?

Answer 9

A fully developed antral follicle

Question 10

Under the influence of gonadotrophins (FSH, LH), antral follicle cells secrete hormones. what do FSH and LH cause?

Answer 10

LH stimulates thecal cells, and these thecal cells secrete the androgens (testosterone,
androstenedione, oestrogens)
FSH stimulates granulosa cells, these granulosa cells convert androgens into oestrogens

Question 11

during the antral stage (developing the antral follicle), what are the granulosa cells doing?

Answer 11

FSH stimulates the granulosa cells so the granulosa cells converts androgens into oestrogen

Question 12

Several primordial follicles begin to develop every day during fertile life, but only one follicle proceeds to ovulation. what is this one follicle called?

Answer 12

dominant follicle

Question 13

in the pre-ovulatory stage, what does LH stimulate (and what does this result in)?

Answer 13

• In the pre-ovulatory stage, LH stimulates secretion of progesterone.
• As a result, oestrogen levels begin to fall slightly while progesterone levels rise.
• At the same time, the granulosa cells lose their receptors for FSH and oestrogen.

Question 14

what happens to the follicle at ovulation?

Answer 14

At ovulation the follicle ruptures and the secondary oocyte enters the
fallopian tube.

Question 15

what happens to the follicle after ovulation?

Answer 15

After ovulation the follicle forms a corpus luteum which is regulated
by LH from the anterior pituitary.

Question 16

are the events of the ovarian cycle and the uterine cycle at the same time?

Answer 16

yes

Question 17

The uterine cycle or menstrual cycle - what happens in response to the ovarian hormones?

Answer 17

A series of cyclic changes in the endometrium in response to ovarian hormones.

Question 18

how many days is the ovarian and uterine/menstrual cycle?

Answer 18

The ovarian and the uterine/menstrual cycles - 28 days (21 to 40 days)

Question 19

what day does ovulation typically happen?

Answer 19

Ovulation around day 14

Question 20

what is the time from ovulation to the beginning of menses (period)?

Answer 20

Menstrual cycle can vary but the time from ovulation to the beginning of menses is almost always 14 or 15 days.

Question 21

what are the 3 phases of the uterine/menstrual cycle?

Answer 21

There are three phases of the menstrual cycle:
Days 0 to 4: Menstrual phase
Days 5 to 14: Proliferative phase
Days 15 to 28: Secretory phase

Question 22

what happens in days 0-4:menstrual phase of the menstrual/uterine cycle?

Answer 22

• During this interval, the superficial functional layer of the thick endometrial lining of the uterus is sloughing off from the uterine
  wall.
• The detached tissues and blood pass through the vagina as menstrual flow (the “period”) for 3 to 5 days.
• The average blood loss during this period is 50 to 150 ml.
• By day 4, growing ovarian follicles are beginning to produce more oestrogens

Question 23

The menstrual cycle is Normally only interrupted by?

Answer 23

Normally only interrupted by pregnancy

Question 24

The menstrual cycle is terminated by?

Answer 24

menopause

Question 25

what are the 2 alternating phases of the menstrual cycle?

Answer 25

Two alternating phases: Follicular phase – presence of maturing follicles Luteal phase – presence of the corpus luteum

Question 26

name the 2 gonadotropins

Answer 26

FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone)

Question 27

what happens in days 5-14: Proliferative phase of the menstrual/uterine cycle?

Answer 27

* this phase is stimulated by a rising level of oestrogens produced by ovaries * The basal layer of the endometrium regenerates the functional layer (this is the layer that's sloughed off in menstruation), glands form in it, and the endometrial blood supply increases. * Straight endometrial glands and spiral arteries elongate in highly vascular stroma * Progesterone receptors * The endometrium once again becomes velvety, thick, and well vascularized. * Ovulation occurs in the ovary at the end of this stage, in response to the sudden surge of LH in the blood.

Question 28

what happens in days 15-28: Secretory phase of the menstrual/uterine cycle? 2 or 3 bullet points

Answer 28

* A rising level of progesterone production by the corpus luteum acts on the oestrogen-primed endometrium and increases its blood supply even more. * Progesterone also causes the endometrial glands to grow and begin secreting nutrients into the uterine cavity. These nutrients will sustain a developing embryo (if one is present) until it has implanted. * Lack of ovarian hormones in the blood causes the blood vessels supplying the functional layer of the endometrium to go into spasms and kink [painful, involuntary muscle contractions] * When deprived of oxygen and nutrients, those endometrial cells begin to die, which sets the stage for menses to begin again on day 28.

Question 29

Formation of Corpus Luteum

Answer 29

LH stimulates the transformation of granulosa cells into the corpus luteum (luteinisation) LH receptors instead of FSH Lipid within the cells ‘yellow body’ * Endocrine gland -Granulosa cells, now called granulosa lutein cells, produce progesterone -Theca interna cells, now called theca lutein cells, produce androgens which are converted to oestrogen

Question 30

Corpus Albicans (day 25 >)

Answer 30

Loss of LH leads to the degradation of corpus luteum (leutolysis) and decreased progesterone secretion Cells replaced by collagen Fibrous ovoid structure * Corpus albicans ‘white body’ * May persist for years

Question 31

in menstruation, what does the Absence of progesterone secretion from corpus luteum lead to?

Answer 31

* Contraction of spiral arteries results in ischemia * Degeneration of stratum functionalis * Shed as menses

Question 32

if pregnancy does take place in the secretory phase, what happens to the oestrogen and progesterone levels?

Answer 32

If fertilization takes place, progesterone and oestrogen levels continue to rise, rather than fall.

Question 33

what is hCG (human chorionic gonadotropin) hormone produced by?

Answer 33

hCG is produced by the developing embryo (specifically the cells that will become the placenta).

Question 34

primary role of hCG?

Answer 34

hCG's primary role is to keep the corpus luteum functioning, so that the corpus luteum continues to produce oestrogen & progesterone.

Question 35

when does hCG levels begin to decrease

Answer 35

hCG begins to decrease when the placenta is developed enough to become the major producer of progesterone and oestrogen.

Question 36

what hormone enables ovarian follicle rupture and release of an oocyte

Answer 36

LH

Question 37

what hormone is essential for the endometrium to become receptive to an embryo

Answer 37

progesterone

Question 38

what hormone can increase libido prior to ovulation

Answer 38

oestrogen

Question 39

what hormone prevents the endometrium from shedding in pregnancy

Answer 39

progesterone

Question 40

what hormone is responsible for growth of the endometrium

Answer 40

oestrogen

Question 41

what hormone is responsible for the thinning of cervical mucus

Answer 41

oestrogen

Question 42

what hormone stimulates (in a pulsatile manner) the anterior pituitary gonadotrophs to produce FSH and LH

Answer 42

GnRH

Question 43

what hormone stimulates granulosa cells within the ovarian follicle to produce oestrogen

Answer 43

FSH

Question 44

what hormone stimulates theca cells within the ovarian follicle to produce androgens

Answer 44

LH