(6) Ch. 22 Ova Development

Front 1

oogenesis
oogonia

Back 1

In the process called __________, ova develop from relatively undifferentiated germ cells called ________.

Front 2

oogenesis

Back 2

________ begins in the first 3 months of embryonic life, when oogonia (diploid) undergo mitosis to yeild 2-4 million clones from which all ova are ultimately derived.

Front 3

primary oocytes

Back 3

These oogonia differentiate into ________ ______, which begin the first meiotic division (meiosis I) with replication of DNA.

Front 4

meotic arrest

Back 4

However, meiosis stops and the primary oocytes enter a state of suspended development known as _______ _______ and remain there until just before ovulation.

Front 5

meiosis I
23
secondary oocyte
first polar body

Back 5

After a female reaches puberty, one primary oocyte per month continues ________ _. Just prior to ovulation, a primary oocytes completes meiosis I to yeild 2 daughter cells possessing __ chromosomes each. One of the daughter cells, called a __________ ______, receives most of the cytoplasm during the cell division and continues to develop further; the other daughter cell, called the ______ ______ _____, degenerates and is lost.

Front 6

secondary oocyte
second polar body
46

Back 6

Only in the event that the _________ ______ is fertilized does meiosis II occur. This second meiotic division yields an ovum, which receives most of the cytoplasm and a ________ _______ _____, which degenerates. The fertilized ovum contains 23 single chromosomes that it inherits from the secondary oocytes plus an equal number that it inherits from the sperm, giving a total of ___ chromosomes.

Front 7

follicle
granulosa

Back 7

As a follicle begins to develop, the follicle cells proliferate into multiple layers around to oocyte and differentiate into ________ cells.

Front 8

preantral stage

Back 8

At this point, the primodorial follicle becomes a primary follicle and this stage of development is called a __________ _______.

Front 9

granulosa
zona pellucida

Back 9

During the preantral stage, _________ cells secret noncellular material that forms a thick membrane btwn them and the oocyte called the _____ _________.

Front 10

gap junctions

Back 10

Because the zona pellucida separates the oocyte from the other tissue, including blood, nourishment to an oocyte is provided by ____ _________ located in cytoplasmic extensions btwn granulosa cells and the oocyte.

Front 11

theca

Back 11

At the preantral stage, certain conn. tissue cells differentiate to form the outer layer of ______ cells. Some follicles DONT develop beyond this stage.

Front 12

antrum
secondary follicle
early antral stage

Back 12

Follicles that continue developing form a fluid-filled cavity called an ______, which increases in size as development continues. At this point, the follicle is called a __________ _______, and the stage of development is called the _____ _______ ______. Some follicles will stop developing at this point.

Front 13

follicular phase
dominant follicle
lost

Back 13

At the beginning of the __________ ______, about 10-25 follicles from the pool of preantral or early antral follicles are recuited to develop further. After about 7 days, one of these follicles, _________ _______, is selected to develop to full maturity. The remaining "contenders" undergo atresia and are ____.

Front 14

FSH
estrogens

Back 14

What hormones are stimulated by the follicles themselves?

Front 15

FSH
estrogen

Back 15

During the follicular phase, plasma ____ levels decrease, which leads to ________ secretion to decrease.

Front 16

late antral stage

Back 16

As the dominent follicle continues to develop into the ____ ______ ______, the antrum grows and displaces some of the cellular tissue around the oocyte.

Front 17

corona radiata
cumulus oorphorus
graffian follicle

Back 17

Several layers of granulosa cells continue to surround to the oocyte, forming the _______ ________ while other granulosa cells form the _______ _________, a bridge of cells that attaches the oocyte and corona radiata to the wall of the follicle, now called a ________ ________.

Front 18

meiosis I

Back 18

Eventually, _________ occurs, and the oocyte (now a secondary oocyte) detaches from the follicle wall and floats freely in the antral fluid, along with the surrounding corona radiata.

Front 19

the wall of the graafian follicle ruptures, and fluid carries oocyte to ovary surface.

Back 19

What is the first thing that happens during the luteal phase?

Front 20

corpus luteum

Back 20

The ruptured follicle is then transformed into a gland called the _____ ______, which secretes estrogens and progesterone.

Front 21

corpus luteum
corpus albicans

Back 21

If the oocyte is not fertilized, the _______ ______ reaches it maximum activity within 10 days of its formation and then begins to degenerate to scar tissue called the ______ ________.

Front 22

menstral phase
proliferate phase
secretory phase

Back 22

What are the names of the phases in the uterine cycle?

Front 23

menstral phase

Back 23

The phase that begins on day 1 and lasts for 3-5 days corresponding to the first few days of the ovarian follicular phase.

Front 24

proliferate phase

Back 24

The phase which lasts for the remainder of the follicular phase (typically from the end of menstruation to day 14)

Front 25

secretory phase

Back 25

The phase which coincides with the luteal phase.

Front 26

The menstrual phase

Back 26

the shedding of the uterine lining

triggered in response to the fall in plasma estrogen and progesterone that occurs as the corpus luteum degenerates

blood vessels begin to constrict, which reduces blood flow to the tissue

the tissue dies and starts to separate from the underlying endometrial tissues, which remain intact.

dead tissue sheds from endometrial surface, which cause blood vessels to rupture and sloughed tissue seeps into vagina from uterus and exits body

Front 27

The proliferation phase

Back 27

begins @ end of menstrual phase

uterus renews itself for possible pregnancy

endometrial tissue grows and myometrial tissue thickens

endometrial gland enlarge, and blood vessels increase in abundance

cervical canal glands secrete mucus that cleanses the inner surface

mucus also helps w/sperm migration through uterus

increased plasma estrogen levels due to activity of dominant follicle

Front 28

The secretory phase

Back 28

endometrium is transformed in such a way as to make it a favorable environment for implantation and subsequent housing and nourishment of the developing embryo.

blood supply increases

endometrial glands enlarge and secrete fluids rich in glycogen, which is used as energy for embryo.

secretions become sticky and viscous forming a "plug" which protects the embryo from harmful things in external environment

promoted by increasing levels of progesterone

the corpus luteum degenerates, causing decreased estrogen and progesterone levels

leads to events of a menstruation