.
Biology of Reproduction, lecture on Adult Female Reproductive Systems
text: Human Reproductive Biology 2nd Edition
- R.E. Jones: Read pages 26-62 for this lecture
VII. Adult Female back to VI. Feedback
A. Reproductive Anatomy
1. Uterus
2. Fallopian Tube or Oviduct
3. Broad ligament
4. Ovary
a. Surface Epithelium
b. Cortex (outer layer)
i. primary oocytes
(female germ cells, found within follicles)
ii. some vertebrates have germinal bed
(1) for continued production of 1o oocytes
3. Medulla (inner layer)
a. arteries, veins, nerves
4. Hilus
B. The Follicle
1. Follicular Wall
2. Oocyte
3. Primordial Follicle 50 mm diameter
a. 1o oocyte
b. membrana granulosa
c. zona pellucida
4. Primary Follicle
a. granulosa becomes cuboidal
b. gains Theca
i. connective tissue
ii. invaded by blood vessels immediately
5. Secondary Follicle
a. up to six layer granulosa
i. cell division = mitosis
6. Tertiary Follicle 25mm diameter
a. Theca externa = connective tissue
b. Theca interna
i. glandular
c. 2-3 layers of granulosa
d. Antral fluid in Antrum
i. filtrate of blood from capillaries in the Theca
e. corona radiata
f. cumulus oophorus
7. Follicular Atresia
a. a female (any mammal) is born with all
the oocytes she'll ever have
i. human embryo has 3.5 million follicles
ii. fish, amphibians, reptiles & birds
have germinal beds
(1) \ can produce 1o oocytes throught life
(a) produced mitotically,
mature to ova meiotically
b. most follicles are lost by atresia
i. can happen at any stage
ii. more prevalent at later, larger stages
(1) atresia often occurs as a result of supporting
(steroidally) the follicle which will ovulate
c. follicular selection
i. very few oocytes are ovulated
(1) larger follicles,
with a greater blood supply,
get a greater share of gonadotropins
(a) \ grow faster
(2) which oocytes begin to grow are probably
controlled by the hypothalamus
via the vagus nerve
ii. many follicles grow and then die
d. those that grow and do not ovulate help make
steroids (E2) for positive feedback
8. Steroid Production
a. one of the 1o functions of follicle cells
b. Estrogens:
any compound that causes the uterus to grow
i. 3 natural estrogens
(1) E2 = estradiol-17b
(2) E1 = estrone
(3) E3 = estriol
c. Progestogens:
any compound that allows embryo
to implant/grow in the uterus
i. P (progesterone) (peripheral)
ii. in the brain
(1) THP = allopregnanolone = 3a-OH-DHP
(2) Preg-S = pregnenolone sulfate
d. Androgens:
any compound which will
stimulate growth of the seminal vesicles
i. potent: most common in men
(1) T = testerone
(2) DHT = dihydrotestosterone
ii. weak: most common in women
(1) DHEA = dehydroepiandosterone
(2) androstenedione
e. steroidogenesis
cholesterol
¯
pregnenolone
¯
17-hydroxypregnenolone
¯
DHEA ® androstenedione
÷ö æ
÷ö
T E1
¯ ø ÷ö
ø ÷ö
E3 E2
i. D5 pathway = ® = main follicular source of steroids from the ovay
(1) Tertiary follicles
Theca Granulosa
*LH
cholesterol ® ® pregnenolone
D5 ÷
÷ transported by diffusion
androstenedione- - - - - - - - - - - - - - - - - ®
¯
T
¯
¯ *FSH
*required E2
9. Corpus Luteum (yellow body)
a. formed after ovulation
b. Luteinization
i. product of LH surge (name of LH)
(1) begins just before ovulation
ii. theca thickens
iii. granulosa divides (mitosis)
(1) very fast
iv. these cells now = luteal cells
v. steroidogenic - D4 pathway = ®
cholesterol
¯
D4
pregnenolone ® ® ® ® ® ® Progesterone
¯ ¯
17-OH-preg 17-OH-P
¯ ¯
DHEA ® ® ® ® ® ® ® ® androstenedione
Theca Luteal cells (granulosa)
D5 cholesterol ® pregnenolone
¯
¯ D4
P
÷ ¯
blood ¯ (small amt)
(most) 17-OH-P
¯
andro
¯
E1 ® E2
vi. 3o follicle = 1/4 P : 3/4 E2
(1) E2 stimulates LH surge via + feedback
(1) \ luteinization
vii. Corpus luteum = 2/3 P : 1/3 E2
10. Follicles (summary) In a woman (age 16-25)/ovary
a. primordial ® 1o ® 2o 79,500 3,300
b. 3o or antral: three categories
i. resting
} 47
ii. ripe
iii. graafian or vesicular 10
c. Pre-ovulatory 0 - 1
C. Oocyte Maturation
1. Primary Oocyte
a. dipoid = 2N
i. humans have 46 chromosomes
ii. = 23 homologous pairs
(1) each pair includes one chromosome contributed
from maternal and 1 from paternal parent
iii. arrested in prophase of meiosis I
b. 99.9% of ovarian oocytes
2. Reduction division (finish Meiosis I)
a. equal division of homologous pairs,
but unequal division of cytoplasm
i. only occurs in germ cells
b. first polar body
i. haploid = 1N
3. Secondary Oocyte
a. haploid
b. ovulated as it begins Meiosis II ® then arrested
4. Meiosis II
a. = mitosis with 1N chromosomes
b. stimulated by sperm penetration
5. 2nd polar body
6. Ootid
D. Ovulation
1. LH ® Oocyte maturation
ø
a. Ovulation
i. hyperemia
ii. stigma formation
iii. ovulation cone (mammals)
(1) LH ® E2 ® surface epithelium
and/or thecal cells ® collagenase
(a) inflammatory response?
smooth muscle contraction?
iv. oocyte - cumulous oophorus attachment breaks
v. fluid oozes out through the open stigma
vi. oocyte flows out with antral fluid
vii. oocyte caught by fimbriated extremity
of the fallopian tube
E. Fallopian Tube = Oviduct = Uterine Tube
1. Ostium = opening
2. Frimbria(e) = fingers
3. Infundibulum
4. Ampulla
a. ampullary-isthmic junction
i. fertilization ususally takes place here
5. Isthmus
6. Intramural
7. Uterotubal junction
8. Cross-section
a. Serosa (squamous epithelium)
b. Smooth Muscle
i. Longitudinal Layer
ii. Circular Layer
iii. each cell contracts rhythmically
in its own phase
- out of phase: no function
- in phase: peristaltic contraction
(1) contractions integrated = coordinated
(2) directional - wave of contraction
squeezes all the way down the tube
c. Mucosa
(mostly connective tissue underlying epithelium)
d. Ciliated columnar epithelium
i. Goblet cells (mucus producing)
F. Uterus
1. myometrium
a. smooth muscle
i. inner circular
outer longitudinal
2. Endometrium
a. epithelial cells
b. uterine glands
c. vascularity
3. Cervix
a. cervical canal leads to vagina
ii. cervical os
(1) internal, external & opening
G. Endometrium
1. Uterine glands
a. so many you cant see the mucosa
b. E2 causes uterine gland growth, hyperemia
i. mediated by growth factors (EGF's, IGF's)
c. P + E2 ® secretion
i. uteroglobin (protein)
d. withdrawl of P + E2 ® death of endometrium
i. sloughing