CH 28 - pregnancy and human development

Question 1

gestation period

Answer 1

time from last mens to birth

Question 2

acrosomal reaction

Answer 2

sperm reaches zona pellucida causing ca channels to influx into the sperm, sperm then release enzymes that creates hole in the zona pellucida

Question 3

in humans is it polyspermy or monospermy

Answer 3

monospermy - only one sperm penetrates oocyte

Question 4

what ensures our monospermy?

Answer 4

OOcyte membrane block = other sperm binding receptors are shed

Zona reaction = entry of sper –> Ca surge –> Cortical reaction = ZIP enzymes destroy zona pellucida sperm binding receptors

Question 5

what happens after sperm penetrates oocyte

Answer 5

oocyte completes meiosis II

sperm and ovum swell –> pronuclei

pronuclei replicate and mitosis begin

Question 6

Zygote to Blastocyst

Answer 6

1. Cleavage = zygote divides rapidly as it moves toward uterus, producing 2 daughter cells called blastomeres –> morula
2. Blastocyst formation = embryo consisting of many cells is now called blastocyst as it reach uterus

Question 7

cells in blastocyst

Answer 7

trophoblast = immunosuppresive, placenta formation, form 4th extraembryonic membrane (chorion)

embryoblast = for extraembryonic membranes

Question 8

cytotrophoblast vs syncytiotrophoblast

Answer 8

cytotrophoblast = becomes “inner” layer of cells surrounding embryoblast

syncytiotrophoblast = digest endometrium lining of uterus

Question 9

what prevents menstruation and shows that one is pregnant

Answer 9

human chorionic gonadotrophin (hCG)

Question 10

what secrets human gonadotrophin

Answer 10

trophoblast cells and later chorion (which is released by trophoblast cells)

Question 11

formation of placenta

Answer 11

originate from both embryonic and maternal tissues

Baby = inner cells and trophoblast form chorion –> chorionic villi + blood vessel –> umbilical cord

Mom = uterus breaks down a bit –> makes blood pool called lacunae –> allows it to pick up nutrients

Question 12

what makes up placenta

Answer 12

baby’s chorionic villi + mom’s decidua basalis

Question 13

decidua basalisdecidua capsularis

Answer 13

part of placenta that expand to accomodate growth –> villi also degenerate as fetus grow

Question 14

T or F placenta secretes hCG from beginning until production of estrogen and progesterone increase

Answer 14

True

Question 15

Why are some pregnancy not viable

Answer 15

if placental hormone (estrogen and progesterone) are not enough when hCG levels begin to go down, endometrium starts degenerating

Question 16

Extraembryonic membrane (amnion)

Answer 16

sac filled with amniotic fluid enveloping the embryo

Question 17

Yolk sac (extraembryonic membranes)

Answer 17

source of earliest blood cells
form part of digestive tube

Question 18

allantois (extraembryonic membranes)

Answer 18

end of yolk sac
base of umbilical cord
become part of urinary bladder

Question 19

notochord

Answer 19

formed from aggregation of mesoderm that serve as first axial support of embryo

Question 20

ectoderm becomes

Answer 20

nervous system and skin

Question 21

endoderm becomes

Answer 21

lining of digestive, respiratory ad urogenital systems and associated glands

Question 22

umbillical arteries

Answer 22

cary deoxygenated blood from fetus to placenta (away from baby)

Question 23

umbillical vein

Answer 23

carry oxygenated blood to fetus

Question 24

human placental lactogen (hPL) or human chorionic somatomammotropin (hCS)

Answer 24

stimulate maturation of breasts, fetal growth and glucose sparing

Question 25

increase CRH --> increase fetal cortisol --> increase placental CRH --> increase cortisol levels. This triggers what

Answer 25

maturation of fetal lungs, production of surfactant protein A

Question 26

Increase cortisol result in hormones

Answer 26

increase estrogen, decrease progesterone cause: cervix dilation, prepare for contraction

Question 27

prostaglandins

Answer 27

initiate rhythmic contractions

Question 28

oxytocin

Answer 28

increase contractile force