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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Female reproductive system
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Female Reproductive Anatomy Ovaries are the primary female reproductive organs
Make female gametes (ova) Secrete female sex hormones (estrogen and
progesterone) Accessory ducts include uterine tubes, uterus, and
vagina External genitalia – external sex organs
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Female Reproductive system anatomy
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Ovaries Ovaries contain the ovarian follicles Each follicle consists of an immature egg (oocyte) Cells around the oocyte are called:
Follicle cells (one cell layer thick) Granulosa and theca cells (when more than one
layer is present) The follicles and the oocytes are going through
cyclic development – ovarian cycle
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Combination of follicles and oocyte development Divided to 2 major periods (phases)
Follicular phase – period of follicle growth (days 1–14) Luteal phase – period of corpus luteum activity (days 14–
28) The 2 phases are “separated” by Ovulation (release of the
secondary oocyte from a tertiary follicle)
The ovarian cycle
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Follicular phase Luteal phaseovulation
http://biology.clc.uc.edu/courses/bio105/sexual.htm
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Follicular development - Folliculogenesis The folliculogenesis occurs during follicular phase Primordial Follicle –flattened granulosa cell layer,
basement membrane, oocyte Primary Follicle – growth of oocyte, zona pellucida
formation, cuboidal granulosa cells Secondary Follicle – add layers of granulosa cells,
formation of theca cells
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Folliculogenesis Early Tertiary Follicle – antrum formation, zona
pellucida thickens, theca interna and theca externa form, basement membrane is still present between theca and granulosa cells, blood vessels are in the theca cell layer but not in follicle
Tertiary/pre-ovulatory/Graffian – full size follicle ready to ovulate; oocyte surrounded by corona radiata (granulosa cells) and attached to follicular wall by the comulus oophorus
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Follicular Phase
A few follicles begin to develop from primordial follicle
Oocyte grows, granulosa cells proliferate
Zona pellucida and antrum form
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Follicular Phase
Dominant follicle continues development, rest regress
Corona radiata develops Graafian follicle = mature follicle Ovulation
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Luteal Phase After ovulation, the ruptured follicle collapses,
granulosa cells enlarge, and along with internal thecal cells, form the corpus luteum
The corpus luteum secretes progesterone and estrogen If pregnancy does not occur, the corpus luteum
degenerates in 10 days, leaving a scar (corpus albicans)
If pregnancy does occur, the corpus luteum produces hormones until the placenta takes over that role (at about 3 months)
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Luteal Phase Ruptured follicle gland = corpus luteum Corpus luteum secretes mostly progesterone Corpus luteum reaches max activity 10 days, then
degenerates
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Corpus luteum
The fate of the corpus luteum depends on fertilization:
If pregnancy does not occur, the corpus luteum
degenerates in 10 days, leaving a scar (corpus
albicans)
If pregnancy occurs, the corpus luteum produces
hormones until the placenta takes over that role (at
about 3 months)
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The Ovarian Cycle
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MALEFEMALE
Spermatids
develop into
MITOSISSTAGE OF CELL DIVISION
46(diploid)
Sisterchromatids
Sisterchromatids
MEIOSIS
Second meioticdivision
Secondary gamete divides.23 chromosomes
(haploid)
First meioticdivision
Primary gamete dividesinto two secondary gametes.
23 chromosomes,duplicated
Spermatogonia
Oögonium
Secondaryoocyte(egg)
Disintegrates
Secondpolar body
disintegrates.
Zygote
Sperm
Oögonia
Secondaryspermatocytes
(may notoccur)
Egg releasedfrom ovary at
ovulation.
Primaryspermatocyte
Spermatogonium
One primary spermatocyteyields 4 sperm.
One primary oocyteyields 1 egg.
Primaryoocyte
FERTILIZATION
Unfertilized eggpasses out of body.
Firstpolarbody
Germ cell proliferation
46 chromosomesper cell (only two
shown here)
DNA replicatesbut no cell division.46 chromosomes,
duplicated
Em
bryo
Em
bryoR
epro
duct
ive
adul
tR
eproductive adult
1
2
3
4
5
6
Oogenesis – oocyte development
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Ovum production Occurs monthly in ovarian follicles Part of ovarian cycle Happens during the Follicular phase (preovulatory)
Oogenesis
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Oogenesis Production of female sex cells by meiosis In the fetal period, oogonia (2n ovarian stem cells)
multiply by mitosis and store nutrients Primordial follicles appear as oogonia are transformed
into primary oocytes Primary oocytes begin meiosis but stall in prophase I
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Oogenesis: Puberty At puberty, one activated primary oocyte produces two
haploid cells The first polar body The secondary oocyte
The secondary oocyte arrests in metaphase II and is ovulated
If fertilized, the second oocyte completes meiosis II, yielding:
One large ovum (the functional gamete) A tiny second polar body
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Oogenesis
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Oogonia (multiple by mitosis until 5th month of fetal development)
Arrested development (until shortly before birth)Primary oocytes (arrest in prophase I)
___________________________________________________________Puberty
Oocyte in Graafian follicle – complete meiosis I
Secondary oocyte first polar bodyArrested in metaphase II
If fertilization occur
Complete meiosis II
Ovum second polar body
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Actions of Estrogens from growing follicle
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Actions of Progesterone from the Corpus luteum
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Uterus
Hollow, thick-walled organ located in the pelvis anterior to the rectum and posterosuperior to the bladder
Body – major portion of the uterus Fundus – rounded region superior to the entrance of the
uterine tubes Cervix – narrow neck which projects into the vagina
inferiorly Cervical canal – cavity of the cervix that communicates with:
The vagina via the external os The uterine body via the internal os
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Uterine Wall Composed of three layers
Perimetrium – outermost serous layer; the visceral peritoneum
Myometrium – middle layer; smooth muscle Endometrium – mucosal lining of the uterine
cavity
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Endometrium Has numerous uterine glands that change in length as
the endometrial thickness changes Stratum functionalis:
Undergoes cyclic changes in response to ovarian hormones
Is shed during menstruation Stratum basalis:
Forms a new functionalis after menstruation ends Does not respond to ovarian hormones
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Uterine Tubes (Fallopian Tubes) and Oviducts Receive the ovulated oocyte and provide a site for fertilization Empty into the uterus via the isthmus Expand distally around the ovary forming the ampulla The ampulla ends in the funnel-shaped, ciliated infundibulum
containing fingerlike projections called fimbriae The uterine tubes have no contact with the ovaries Beating cilia on the fimbriae create currents to carry the oocyte
into the uterine tube The oocyte is carried toward the uterus by peristalsis and ciliary
action
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Uterine tubes (Fallopian tubes or oviducts) Infundibulum
End closest to the ovary with numerous fimbriae Ampulla
The middle portion, widest and longest portion Isthmus
A short segment connected to the uterine wall The mucosa of the uterine tube has ciliated simple
columnar epithelial cells that beat toward the uterus and, with the help of muscular contractions of the tube, transmit the egg in that direction.
Fertilization occurs in uterine tube (ampulla)
The Uterine tubes
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Repeating series of changes in the endometrium Menses
Degeneration of the endometrium Menstruation
Proliferative phase Restoration of the endometrium
Secretory phase Endometrial glands enlarge and accelerate their rates
of secretion
Uterine cycle
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Beginning of new cycle - Menstrual Phase of the Uterus
If fertilization does not occur, the corpus luteum degenerates and estrogen and progesterone levels decrease.
The lack of estrogen and progesterone leads to the collapse of the endometrium, which in turn leads to menstruation.
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Menstrual and prolifarative phases (corresponds Follicular Phase of Ovary)
FSH and LH increase during follicular phase because progesterone concentration is low and therefore negative feedback on these pituitary hormones is low.
FSH and LH stimulate primary follicles (containing primary oocytes) to grow and stimulate their theca cells to produce estrogen.
Estrogen leads to a thickening of the endometrium.
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The one dominant follicle (Graafian follicle) survives because it is hyperresponsive to FSH and can maintain itself
even under low FSH it also becomes sensitive to LH.
LH surge appears because increased estrogen exerts a positive feedback effect on the LH releasing mechanism of pituitary.
LH surge leads to release of the primary oocyte (ovulation)
Menstrual and prolifarative phases (corresponds Follicular Phase of Ovary)
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Secretory Phase of the Uterus (corresponding to Luteal Phase of Ovary )
The now empty follicle, corpus luteum, starts secreting progesterone that exert a negative feedback on secretion from LH and FSH, preventing new follicles from maturing.
Progesterone converts the endometrium into a secretory tissue full of glycogen and blood vessels, ready to receive a fertilized egg.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26-13 (2 of 2)
The Uterine Cycle
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Complex Hormonal Control of Two Cycles Ovarian and uterine cycles are controlled by
several hormones, which display complex interactions
Extra-ovarian hormones GnRH from the hypothalamus FSH and LH from the anterior pituitary
Ovarian hormones Estrogen Progesterone Inhibin
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin CummingsDAYS
36.4
36.7
7 14 21 28/028/0
Follicular Phase Ovulation Luteal Phase
Phases of theUterine Cycle
Phases of theOvarian Cycle
Basal bodytemperature
(–C)
Uterinecycle
Ovarianhormone
levels
Ovariancycle
Gonadotrophichormone
levels
Primaryfollicle Theca Ovulation
Corpusluteum
formation
Maturecorpusluteum
Corpusalbicans
Progesterone
MENSES PROLIFERATIVEPHASE
SECRETORY PHASE
InhibinEstrogen
Antrum
LH
FSH
Figure 26-13 (4 of 4)
Corpus Luteum Degenerates and Ceases Hormone Production
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LHFSH
GnRH
Androgens
Estrogens
(a) Early to mid-follicular phase
Follicle
Granulosacells
Thecalcells
(b) Late follicular phase and ovulation (d) Late luteal phase
FSH LH
New folliclesbegin todevelop
Corpusluteum
dies
Tonic secretionresumes
Corpus luteum
Progesterone
Ovum
LHFSH
Follicle
Estrogen andprogesterone
FSH LH
Corpus luteum(from ovulated
follicle)
EstrogenProgesterone
Inhibin
GnRHGnRH
secretes
(c) Early to mid-luteal phase
Estrogen
Inhibin
Follicle
Granulosacells
Thecalcells
Inhibin
High estrogenoutput
Small amount ofprogesterone
Androgens
LHFSH
GnRH
Pituitary Hypothalamus
Figure 26-14 (4 of 4)
Hormonal Control of the Menstrual Cycle: Late Luteal Phase
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Menstrual phase Proliferetive phase
Secretory phase
Follicular/preovulatory phase Luteal/postovulatory phase
Days 1-5 6-14 15-28
Hormones All low High estrogen; low progesterone
High progesterone; low estradiol
Endometrium
Necrotic tissue falls away from the uterine wall
Repaired and become thicker
Very well vascularized. Thick
Glands Not developed. Simple Gland proliferate Glands increase in size and secrete nutritional substances
Follicles Primordial follicles develop into primary and then secondary follicles
One follicle continue to grow into Graafian follicle and ovulate by the end of this phase
No follicular development. Corpus luteum is present
Oocyte/s First meiosis; arrested in prophase I First meiosis completed; secondary oocyte arrested in metaphase II ovulates
If fertilization occur second meiosis is completed
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Mammary Glands Pectoral fat pad Modified sweat glands consisting of 15-25 lobes that
radiate around and open at the nipple Areola – pigmented skin surrounding the nipple Lobes contain glandular alveoli that produce milk in
lactating women alveolar glands pass milk to lactiferous ducts, which
open to the outside
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Mammary Glands nonlactating breast consists mostly of adipose and
collagenous tissue and contains very little mammary gland.
Lactating develops during pregnancy, it exhibits 15–20 lobes arranged around the nipple,
each drained by a lactiferous duct. These dilate to form a lactiferous sinus opening into the nipple.