lecture 15: reproductive system II

Question 1

what are the functions of of the reproductive system?

Answer 1

• produce ovaries
• receive sperm, facilitate fertilizations
• house and nourish developing embryo, give birth ( development)
• lactate, feed young ( caring for newborns)
• make cells and fertilizations + development and care post birth

Question 2

what are ovaries

Answer 2

female gonad (either side) responsible for making egg cells or ova

Question 3

how are ovaries held

Answer 3

held in place by several ligaments, not just floating

Question 4

what do ovaries produce

Answer 4

gametes ( egg cells) via oogenesis -> oocyte

sex hormones - estradiol, progesterone

Question 5

oviducts ( fallopian tubes)

Answer 5

• tubes between ovaries & uterus

-

Question 6

what is the function of oviducts

Answer 6

• collects secondary oocytes from the ovary

- movenet though oviduct is added by cilia and contractions

Question 7

what is the site of oviducts

Answer 7

• site of fertilization ( where sperm encounters 2° oocyte)

- doesn’t become egg until after fertilizations

Question 8

uterus

Answer 8

• pear- shaped, - size of fist
• 2 layers: myometrium: thick wall of smooth muscle
• endometrium: lines lumen daces inner cavity

Question 9

the uterus is the site of ….

Answer 9

embryonic development: (expands during pregnancy’s), highly elastic

Question 10

endometrium

Answer 10

1. lines lumen - connective tissue, gland, blood vessels
2. thickens each month - prepare for pregnancy: (embryo arrives in uterus, implants in endometrium, responsible for nutrients for embryo
3. fertilization -> embryo implants
4. no fertilization -> sloughed off (lost) -> menstruation (shedding of endometrium lining)

Question 11

cervix

Answer 11

• closes uterus and seperates it from vagina

- comonn site of cancer

Question 12

vagina

Answer 12

• elastic muscular tube
• extends to outside of body
• receives penis and sperm ( during intercourse)
• birth canal ( fetus goes through vagina from uterus)

Question 13

vulva

Answer 13

• external genitalia

- covers external openings

Question 14

oogenesis

Answer 14

• development of mature eggs (making egg cells)

Question 15

oogenesis in embryo

Answer 15

• primordial germ cells (2n)
• mitosis -> oogonia (2n)
• form during development, no new oogonia after birth
• mitosis -> 1 ° oocyte (2n)

Question 16

1° oocyte ( forms during embryonic development)

Answer 16

• begin meiosis
• arrest in prophase I
• at birth, avg female: 1-2 million 1° oocytes have arrested in prophase I of meiosis, all wont last
• 200k left by sexual maturity
• dormant in prophase I until acted on by hormones after puberty and restart process of oogenesis

Question 17

oogenesis after puberty

Answer 17

-occurs in follicle: structure within ovary, group of cell with 1° oocyte in the middle

Question 18

the follicle contains

Answer 18

• 1° oocyte on inside
• shell of lots of follicle cells - protective barrier
• zona pellucida

Question 19

zona pellucida

Answer 19

thick glycoprotien layer between follicle cells & oocyte (separates outer and inner layers)

Question 20

each month

Answer 20

a) 6-12 follicles matures
b) primary oocyte grows, follicle cells proliferate
c) After ~1 week - largest of follicle (wins the race) continues, others stop, disintegrates

Question 21

1° oocyte division

Answer 21

• once mature, release cell into oviduct
• restart and completes meiosis I 8-10 hours before release (ovulation)
• unequal cytokinesis
• starts meiosis II
• arrests at metaphase II

Question 22

unequal cytokinesis

Answer 22

1. 1 one polar body (n) very small, gets rid of half the genome
2. one 2° released from follicle during ovulation

Question 23

ovulation

Answer 23

a) Once 1st meiotic division complete
b) As 2° oocyte matures → follicle that contains it moves to surface of ovary
c) Follicle cells secrete fluid, estrogens, proteolytic enzymes → break down ovary wall
d) 2° oocyte ejected into oviduct
(1) Follicle ruptures

Question 24

corpus luteum

Answer 24

“yellow body” remnants of follicle that is left behind

portionof follicle left in ovary after ovulation

Question 25

corpus luteum develops into

Answer 25

temporary endocrine glands

Question 26

the corpus luteum secretes

Answer 26

• estrogens

- progesterone (1000x more than estrogens)

Question 27

2°

Answer 27

a) If sperm enters (fertilized) → completes meiosis II → mature egg contain sperm head (with sperm genome) - oogenesis complete
b) If no sperm enters → disintegrates
(1) Corpus luteum dies (luteolysis) → Menstruation (triggers breakdown of endometrium lining)
c) Getting rid of temporary endocrine gland → New follicle next