The fertile female

Question 1

How can you tell when an animal with an oestrus cycle is ready for ovulation?

Answer 1

mainly behaviour

Question 2

what is ovulation?

Answer 2

release of an ovum

Question 3

At what point during meiosis do the oocytes pause?

Answer 3

when they are primary immature oocytes

Question 4

What do the primary immature oocytes associate themselves with?

Answer 4

Primordial follicles

Question 5

What does the LH surge do in oogenesis?

Answer 5

Forms a secondary oocyte with a polar body

Question 6

What is a follicle?

Answer 6

a functional unit within the ovary

Question 7

What is recruitment

Answer 7

when primordial follicles develop in each cycle

Question 8

What is the zona pellucida?

Answer 8

The outer protective layer of the oocyte

Question 9

When do the primordial follicles form?

Answer 9

when the primary oocytes do

Question 10

What layer is avascular and therefore is required for the oocyte to take up nutrients?

Answer 10

Granulosa

Question 11

What is the function of follicular fluid?

Answer 11

takes up space within the follicle further increasing the size

Question 12

What triggers ovulation?

Answer 12

Pre-Ovulatory surge

Question 13

What is another name of a collapsed follicle?

Answer 13

corpora haemorrhagica

Question 14

What forms after ovulation?

Answer 14

it becomes an oocyte

Question 15

What is the follicular phase of the menstrual cycle?

Answer 15

When the follicle is developing

Question 16

What is the luteal phase of the menstrual cycle?

Answer 16

When you have a corpus luteum producing progesterone

Question 17

What is oestrus a marker of in animals?

Answer 17

The end of the follicular phase/ ovulation

Question 18

What is the function of prostoglandin?

Answer 18

Main luteolytic agent (causes luteolysis)

Question 19

What is atresia?

Answer 19

Degradation of the follicles that are not recruited in the menstrual cycle

Question 20

Which hormone triggers selection?

Answer 20

FSH

Question 21

When does the oocyte begin meiosis I?

Answer 21

Meiosis I begins before puberty but then the oocyte becomes arrested in prophase I

Question 22

When is meiosis I completed?

Answer 22

The nuclear arrest is lifted during the LH surge (puberty) so meiosis I is completed and a secondary oocyte forms

Question 23

What are the two main forms of female reproductive cycle?

Answer 23

The menstrual cycle and the oestrus cycle

Question 24

What does puberty do to primordial follicles?

Answer 24

Stimulates the development of primary follicles from primordial follicles

Question 25

What type of follicle is ovulated?

Answer 25

Mature/Graafian follicle

Question 26

At what stage is the zona pellucida formed?

Answer 26

Primary follicle

Question 27

At what stage do thecal cells develop around the granulosa cells?

Answer 27

Secondary follicle

Question 28

What is the function of the follicular fluid (antral cavity)?

Answer 28

To increase follicle size

Question 29

What is the function of granulosa cells proliferating?

Answer 29

To increase follicular size

Question 30

How do we protect developing gametes from the blood supply?

Answer 30

Thecal cells, basal lamina and granulosa cells

Question 31

What is the consequence of granulosa cells being avascular?

Answer 31

No blood cells therefore the granulosa cells must regulate development/ nutrition

Question 32

What does the binding of androgens to thecal cells on the follicle do?

Answer 32

Stimulates the proliferation of granulosa cells and the production of some oestrogen

Question 33

What does FSH binding to granulosa cells trigger?

Answer 33

The production of enzymes that produce oestrogen from teh androgens produced by the thecal cells

Question 34

What does oestradial trigger?

Answer 34

Stimulates even more granulosa cell proliferation

Question 35

What happens to the endocrine nature of the follicle after the pre-ovulatory LH surge?

Answer 35

Granulosa cells loosen, there is increased blood flow to the theca cells, stops the synthesis of oestrogen and starts synthesising progesterone

Question 36

When does a secondary oocyte become a zygote?

Answer 36

After it has been fertilized

Question 37

What do the granulosa cells become after ovulation?

Answer 37

Large luteal cells (high lipid concentration)

Question 38

What do the thecal cells become after ovulation?

Answer 38

Small luteal cells

Question 39

When does luteolysis occur?

Answer 39

Over a period of 1-3 days in the late luteal phase

Question 40

Where is Pgf2A produced?

Answer 40

In primates and dogs- ovary In most other animals- uterine endometrium

Question 41

What cells produce oxytocin in response to pgf2a?

Answer 41

The large luteal cells (which also causes positive feedback of even more pgf2a)

Question 42

When does ovulation occur during the oestrus cycle?

Answer 42

at the end of the follicular phase

Question 43

What is dioestrus characterised by?

Answer 43

Functional corpus luteum and high progesterone levels

Question 44

What is proestrus characterised by?

Answer 44

Significant increase in oestradiol

Question 45

What is oestrus characterised by?

Answer 45

High oestradiol and sexual receptivity

Question 46

What happens to the egg cell before birth?

Answer 46

Primordial germ cell divides by mitosis to become oogonia/ primary oocyte Primary oocyte then undergoes meiotic prophase to double its chromatids (46 chromosones/ chromatids to 46 chromosoneds and 96 chromatids) (still 2n)

Question 47

What occurs to the egg cell post-puberty? | Oogenesis

Answer 47

Once a month an LH surge causes the meiotic arrest to be liftted Meiosis 1 is completed and a secondary oocyte is formed (n=23) This oocyte is then ovulated and fertlized producing a 2n zygote

Question 48

How often is meiosis 1 completed?

Answer 48

It is completed by one primary oocyte each month

Question 49

What occurs during ovulation in terms of hormones

Answer 49

LH pulses stimulate the granulosa cells to produce estrogen, the increase in estrogen stimulates the pre-ovulatory LH surge (surge centre) This causes a secondary oocyte to form and ovulate and changes to occur (granulosa cells loosen, follicle size increases, granulosa cells withdraw from the zona pellucida) Less estrogen is produced and more progesterone is produced

Question 50

What is a corpus hemorrhagicum?

Answer 50

ruptured follicle

Question 51

What is the fate of the follicle after ovulation?

Answer 51

Fibrin core forms a blood clot, granulosa and thecal cells break down Basal lamina breaks down Granulosa cells hypertrophy to large luteal cells Theca cells become small luteal cells