a&p 2 - reproductive system (females)

where are oocytes produced?

ovaries

females gametes

oocytes

oocytes travel from ___

ovaries through the ducts

external genitalia of the female reproductive system includes:

labia minora, labia majora, & clitoris

the female reproductive system produces __

gametes & sex hormones

the female reproductive system supports & ___

protects developing embryo

the female reproductive system nourishes ___

newborn infant

the ovaries produce __

female gametes (oocytes)

the ovaries secrete ___

female sex hormones (estrogen & progesterone)

the ovaries female sex hormones & ___

inhibin

inhibin

a hormone involved in negative feedback control of FSH

what is oogenesis?

the process of ovum production

when does oogenesis begin and end?

begins before women’s birth and ends at menopause

where does oogenesis take place?

in the ovaries, each month as part of ovarian cycle

oogonia

female diploid reproductive stem cells

what do oogonia complete before birth?

mitosis

what are the first cells that make eggs?

oogonia

what do oogonia produce?

primary oocytes

when do primary oocytes begin?

meiosis while the baby is still in the womb

primary oocytes pause at ___

prophase I until puberty

only about ___ of primary oocytes survive

20%

what happens to the 80% of primary oocytes that don’t survive?

they break down naturally by atresia

at birth, females are presumed to have ___

a lifetime supply of primary oocytes

each month after puberty, ___

a few primary oocytes are activated

Only __ oocyte is chosen each month to __

one; continue development into a mature egg (resume meiosis I)

when the one oocyte that is chosen each month to continue developing, it divides, making ___

two haploid cells of different sizes

when the one oocyte that is chosen each month to continue developing, it divides, making two haploid cells of different sizes:

secondary oocyte & first polar body

secondary oocyte

the large cell with almost all the cytoplasm of the original cell (this one can be fertilized).

first polar body

the tiny leftover cell that usually dies

the secondary oocyte is stuck in ___

metaphase II until ovulation

what is the egg cell released at ovulation?

secondary oocyte

if no sperm enters, ___

the secondary oocyte just breaks down

if sperm enters, ___

the secondary oocyte completes meiosis II and makes: ovum & second polar body

if sperm enters, the secondary oocyte completes meiosis II and makes:

ovum & second polar body

ovum

the true egg that can fuse with sperm

Second polar body

another tiny discard cell

oogenesis and spermatogenesis are both forms of meiosis, but have 2 major differences:

uneven cytoplasm division & secondary oocyte vs mature egg

in sperm production, the cell divides ___

evenly; so each sperm is about the same size

in egg production, the cytoplasm is divided ___

unevenly; the secondary oocyte gets almost all the cytoplasm, the other cells, polar bodies, are small cells that eventually die bc they get barely any cytoplasm

what is released during ovulation?

not a mature egg, the secondary oocyte

secondary oocyte pauses in meiosis until __

a sperm arrives

only if a sperm fertilizes it, will the oocyte __

finish meiosis II and become a true ovum (mature egg)

the oocyte will only finish meiosis II and become an ovum if ___

a sperm fertilizes it

ovarian follicles

sites of oocyte growth & meiosis of oogenesis

primordial ovarian follicle

primary oocyte surrounded by a single layer of follicle cells

primary ovarian follicle

the follicle cells get bigger (become cuboidal in shape), start dividing, and form multiple layers

primary ovarian follicle produces __

estrogen

in the primary ovarian follicle, a layer called ___

the zona pellucida forms

zona pellucida

a layer that helps move nutrients from the follicle cells into the oocyte

secondary ovarian follicle

The follicle wall gets thicker and starts making fluid

Only a few primary follicles actually grow to ___

secondary ovarian follicle

tertiary ovarian follicle (testicular follicle)

Fluid builds up inside the follicle, creating spaces between cell layers

Tertiary ovarian follicle (vesicular follicle) grows about ___

twice as big as a secondary ovarian follicle.

ovarian cycle

monthly series of events in the ovary that prepare and release an egg

In a typical 28-day cycle, there are two main phases:

follicular phase & luteal phase.

follicular phase -

period of follicle growth (days 1-14)

what phase is day 1-14 of ovarian cycle?

the follicular phase

follicular phase cycle:

primordial follicle → primary follicle → secondary follicle → late secondary follicle → vesticular follicle

follicular phase cycle: primordial follicle → primary follicle → secondary follicle

granulosa cells multiply and form several layers around occyte; and small amounts of fluid begin to accumulate btwn the granulosa cells

follicular phase cycle: primordial follicle → primary follicle → secondary follicle → late secondary follicle

theca folliculi & granulosa cells cooperate to produce estrogen

in the late secondary follicle stage,

Theca cells first make androgens (male hormones), which granulosa cells then turn into estrogen

in the late secondary follicle stage, a layer called the ___

zona pellucida forms around oocyte

in the late secondary follicle stage, more __

fluid accumulates btwn granulosa cells

follicular phase cycle: primordial follicle → primary follicle → secondary follicle → late secondary follicle → vesticular follicle

A big fluid-filled space called the antrum forms, pushing the egg (oocyte) to one side and surrounding it with protective cells (corona radiata)

in the vesicular/Graafian follicle stage, the follicle grows __

so large it starts to bulge from the surface of the ovary

in the vesicular/Graafian follicle stage, inside, __

the primary oocyte finishes meiosis I, making: a secondary oocyte & first polar body

when does ovulation occurs?

midcycle- day 14

during ovulation, the ovary wall ___

ruptures and releases the secondary oocyte (egg) with its surrounding protective cells (corona radiata)

Mittelschmerz

twinge of pain sometimes felt at ovulation

Sometimes a woman may feel a small pain at ovulation — this is called:

Mittelschmerz

1-2% of ovulations release ___

more than one secondary oocyte, which if fertilized, results in fraternal twins

If one egg is fertilized and then splits, __

results in identical twins

luteal phase -

period of corpus luteum (days 14-28)

in the luteal phase, __

the ruptured follicle collapses

the remaining cells in the luteal phase form a structure called the ___

corpus luteum

the corpus luteum secretes ___

Progesterone & estrogen

if no pregnancy:

The corpus luteum breaks down after about 10–14 days, leaving a small scar called the corpus albicans

if pregnancy occurs:

The corpus luteum keeps making hormones (mostly progesterone) to maintain pregnancy until the placenta takes over around 3 months

only __ of women have a 28 day cycle

10-15%

which phase of the ovarian cycle varies?

follicular phase

which phase of the ovarian cycle is constant?

luteal phase

the follicular phase ___, hence __

varies; different length of cycles in different females

the luteal phase ___; always ___

is constant; 14 days from ovulation to end of cycle for all females

the reason that there is different lengths of cycles is because __

the follicular phase varies

ovarian follicles

specialized structures in cortex of ovaries where oocyte growth & meiosis occur

the Fallopian tubes receives the ___

ovum after ovulation

the uterine tubes are also called the __

Fallopian tubes

the Fallopian tubes have 4 parts:

fimbriae, infundibulum, ampula, & isthmus

how long does it take for the egg to travel to the uterus?

about 3-4 days

It usually takes the egg ___ to travel to the uterus

3-4 days

Fertilization must happen within ___

12–24 hours after ovulation, usually in the infundibulum

if fertilization is to occur, oocytes must meet sperm within ___

first 12-24 hours, in infundibulum

if egg is not fertilized:

it breaks down in the tube; it does not finish meiosis; it is shed with the next period

the uterus protects ___

nourishes, and removes wastes for developing embryo & fetus

the uterus contracts to ___

help eject fetus at birth

the uterine wall has 3 layers:

the endometrium, myometrium, and perimetrium

the inner endometrium of the uterine wall has two layers:

functional zone & basilar zone

the functional zone of the endometrium

the top layer that changes each month and is shed during menstruation

the basilar zone of the endometrium

the bottom layer that stays and rebuilds the functional zone after each cycle

the myometrium of the uterine wall

muscle layer that contracts during labor to push the baby out