Lecture 21: Female

Question 1

Describe primordial germ cells in females

Answer 1

Develop from the germinal epithelium of the indifferent gonad early in embryonic development
They migrate into the future ovaries and become : OOGONIA

Question 2

Describe oogonia

Answer 2

Surrounded by a single layer of nongerminal granulosa cells

Question 3

Oogonium + granulosa cells =

Answer 3

primordial follicle

Question 4

Ovum =

Answer 4

primary oocyte

Question 5

The primary oocyte begins the process of meiosis but is arrested during what stage?

Answer 5

diplotene stage of prophase I

*all primary oocytes are arrested during the diplotene stage of meiosis I during embryonic development

Question 6

Most of the primary oocytes will become ____ before birht

Answer 6

atretic = the congenital absence, or the pathological closure, of an opening, passage, or cavity.

Question 7

After birth, how may primary oocytes remain out of the initial number of oogonia cells?

Answer 7

500,000 out of 7 million

Question 8

Beginning at puberty, what happens

-female

Answer 8

One of the primary oocytes will complete the first stage of meiosis to become A secondary oocyte + polar body

Question 9

Secondary oocytes complete the second half of meiosis and become what?

Answer 9

Ootid + polar body

Question 10

When does fertilization occur?

Answer 10

At the second metaphase stage of oogenesis

Therefore, an immature egg is fertilized

Question 11

Why may meiosis not be completed?

Answer 11

Because no fertilization occurs

Question 12

One complete menstrual cycle lasts how many days?

Answer 12

28

Question 13

What are the ovarian phases?

Answer 13

Days 5-14: Follicular growth
Day 14: Ovulation
Days 14-23: Development of corpus luteum
Days 24-28: Regression of corpus luteum

Question 14

What are the Uterine phases?

Answer 14

Days 1-5: Menstruation
Days 4-14: Proliferation
Days 14-28: Secretion

Question 15

What hormone is released from the hypothalamus?

Answer 15

Gonadotropin releasing hormone (GnRH)

Question 16

What is the secretion pattern of GnRH?

Answer 16

Increases much less drastically than the other two sources.

It is secreted in short pulses averaging once every 90 minutes, as occurs in males

Question 17

What are the anterior pituitary sex hormones?

Answer 17

FSH, LH

Question 18

What are the ovarian hormones?

Answer 18

Estrogen and progesterone

Question 19

Describe the anterior pituitary sex hormones in females

Answer 19

FSH, LH
Almost no secretion throughout childhood
Small glycoproteins with MW of 30K
Combine with highly specific receptors in ovarian target cell membranes
Signal transduction involves cAMP second messenger system in most instances leading to formation of protein kinase and multiple phosphorylations

Question 20

Primordial follicles throughout childhood do what?

Answer 20

Provide nourishment for the ovum

Secrete oocyte maturation-inhibiting factor that keeps ovum suspended in its primordial state

Question 21

What is the secretion pattern of GnRH?

Answer 21

It is secreted in short pulses averaging once every 90 minutes, as occurs in males

Question 22

Describe the changes in the ovary leading up to the production of secondary follicles

Answer 22

The first stage of follicular growth is moderate enlargment of the ovum itself, which increases in diameter 2-3x
Followed by growth of additional layers of granulosa cells in some of these follicles -> secondary follicles

Question 23

What hormones have an slight increase in concentration of during the first few days of the cycle?

Answer 23

FSH and LH
Increase if FSH is slightly greater than LH
FSH increase precedes increase in LH

Question 24

The increase of FSH and LH causes what?

Answer 24

Growth of multiple follicles

Question 25

What forms theca?

Answer 25

Spindle-shaped cells around follicles form multiple layers around each follicle

Question 26

The early grwoth of follicle is stimulated with what?

Answer 26

FSH

Question 27

What does the theca interna become?

Answer 27

Cells become epithelioid and develop the ability to secrete estrogen and progesterone

Question 28

What does the theca externa become?

Answer 28

Will become the protective capsule of the developing follicle

Question 29

What do granulosa cells secrete?

Answer 29

Secrete a follicular fluid containing a high concentration of estrogen This causes and antrum to appear

Question 30

What hormone causes androgens to become estrogens?

Answer 30

FSH cascade in granulosa cells

Question 31

What hormone causes cholesterol in the theca cells to become pregnenolone?

Answer 31

LH | Cholesterol->pregnenolone->progesterone->androgens

Question 32

What leads to the follicle rupturing?

Answer 32

Follicule swelling with plasma (hyperemia and prostaglandin secretion) And weakening of follicle wall with collagenase

Question 33

Why is there an elevation of body temperature shsortly after ovulation?

Answer 33

prostaglandins

Question 34

Describe the changes in the uterus during the proliferation stage:

Answer 34

Estrogen phase - occurs before ovulation Most endometrium has been desquamated at the beginning The only epithelial cells left are thos in the deeper portions of the glands and crytps Estrogen causes stromal and epithelial cells to rapidly proliferate Endometrial surface re-epithelialized within 4-7 days after the beginning of menstruation Progressive thickening due to increase in # of stromal cells and grwoth of endoometrial glands Glands secrete a thin, stringy mucous

Question 35

Describe the changes in the uterus during the secretory stage

Answer 35

Progesterone phase progesterone and estrogen secreted in large quantities by corpus luteum Progesterone cause swelling and secretory development of endometrium Glands increase in tortuosity Excess of secretory substances accumulates in glandular epithelial cells Results- highly secretory endometrium that contains stored nutrients Uterine milk provides nourishment for early dividing ovum

Question 36

Describe the changes in the uterus during menstruation

Answer 36

Corpus luteum suddenly involutes about 2 days before the end of the cycle and decreases secretion level Reduction in estrogens and progesterones Decreased stimulation of endometrial cells is followed by involution of endometrium itself 24 hours before the beginning of the onset of menstruation, tortuous blood vessels leading to the muscosal layers become vasospastic, leading to necrosis of endometruim

Question 37

What effect does estrogen have on primary and secondary female sex characteristics

Answer 37

. look at page 993-995