Lecture 21 Flashcards by Danielle Rabjohn

What is capacitation

a maturation sperm must undergo in order to fertilize an egg

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when does capacitation occur

once sperm is in the female tract

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where do you find capacitation inhibiting factors

seminal fluid

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What 2 things occur after capacitation

higher motility pattern (faster flagellum)
plasma membranes become more fragile

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What does a more fragile sperm membrane do for the sperm

facilitates acrosome reaction

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what is the acrosome reaction

fusion of acrosomal membrane and PM and releasing of enzymes

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How can IVF induce capacitation

by washing sperm/ running them through a Percoll gradient

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What induces the acrosome reaction

Binding of sperm to zona pellucida

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What is polyspermy

when more than 1 sperm penetrate the oocyte

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What is it called when more than 1 sperm penetrates the oocyte

Polyspermy

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How does capacitation occur

Female secretions remove protein and some cholesterol that makes acrosomal membranes tough and stable

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Name two mechanisms that prevent polyspermy

Oocyte membrane block
Cortical reaction

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The cortical reaction helps f=prevent

polyspermy

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the membrane block helps prevent

Polysperm

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Describe the oocyte membrane block

Once a sperm binds, the oocyte sheds any other receptors so that no other sperm can bind

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Waves of what are released when the sperm and oocyte membranes fuse

Calcium

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What does the wave of calcium from the oocyte’s endoplasmic reticulum into the cytoplasm cause

The cortical reaction

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What is the cortical reaction

exocytosis of granules located just inside the plasma membrane

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What occurs in the cortical reaction

granules from the PM contain enzymse that destroy the zona pellucida’s sperm-binding receptors and harden the zona pellucida

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What is the male pronucleus

when the sperm’s nucleus swells to about 5 times it’s original size

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what is it called when the sperm’s nucleus swells to about 5 times it’s original size

male pronucleus

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an efflux of what allows the oocyte to complete meiosis II

zinc

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what makes the oocyte complete meiosis II

fertilization

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what is it called when the ovum nucleus swells

female pronucleus

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what is the female pronucleus

when the ovum nucleus swells

when does the female pronucleus appear

when meiosis II is complete

what occurs between the two pronuclei as they approach one another

they fuse, and form the 2N of the zygote

Describe cleavage

period of fairly rapid mitotic divisions of the zygote without intervening growth

what is the goal of cleavage

produce small cells with a high surface-to-volume ratio, which enhances their uptake of nutrients and oxygen and the disposal of wastes

the first cleavage division of the zygote produces two identical cells known as

blastomeres

what is a morula

a cluster of cells formed 72 hours after fertilization

what is the cluster of cells formed 72 hours after fertilization

the morula

when does the zona pellucida start to break down

4-5 days after fertilization

what is the structure inside the zona pellucida as it starts to break down

blastocyst

what are the flattened cells in a single layer around the blastocyst

trophoblast cells

what are the 20-30 rounded cells clinging to the inside of the blastocyst

embryoblast

what are embryoblast cells

the 20-30 rounded cells clinging to the inside of the blastocyst

what are trophoblast cells

the flattened cells in a single layer around the blastocyst

what cells protects the blastocysts from the mother's immune cells

trophoblast

what cells make a major contribution to the choriion

trophoblast

what cells becomes the two layered embryonic disc

embryoblast

How many days after ovulation does implantation begin

6-7 days

what occurs 6-7 days after ovulation

implantation

what allows the endometrium of the uterus to become receptive to implantation

surging levels of estrogens and progesterone

what binds the trophoblast to the endometrial epithelum

cell adhesion molecules

what two layers does the trophoblast proliferate into after implantation

cytotrophoblast syncytiotrophoblast

what is the innermost layer of cells of the blastocyte that the trophoblast proliferates into

cytotrophoblast

what is the outermost layer of cells of the blastocyte that the trophoblast proliferates into

syncytiotrophoblast

why does the embryo rescue the corpus luteum

to prevent mentruation and flushing away the newly implanted embryo

How does the embryo rescue the corpus luteum

Its syncytiotrophoblast secretes human chorionic gonadotropin

what hormone does human chorionic gonadotropin act like

lutenizing hormone

what does hCG prompt the corpus luteum to do

secrete progesterone and estrogens

what helps prevent the mother's immune system from rejecting the IMPLANTED embryo

hCG

what makes hCG

sycytiotrophoblast

what does the syncytiotrophoblast secrete

hCG

between the second and third month, what assumes the role of progesterone and estrogen production

placenta

how does the implanted embryo initially obtain its nutrition

by digesting endometrial cells

what is placentation

formation of the placenta

what is the name for formation of the placenta

placentation

what is the temporary pancake shaped organ

placenta

what is the chorion

outermost fetal membrane

what is the outermost fetal membrane used to form the placenta

chorion

what two things form the chorion

trophoblast associated mesoderm

what is the decidua basalis

endometrium that lies beneath the embryo

what is the endometrium that lies beneath the embryo

decidua basalis

what is the decidua capsularis

the endometrium surrounding the uterine cavity face of the implanted embryo

decidua capsularis

what is the function of the foramen ovale

diverts blood from the right atrium to the left atrium

what diverts blood from the right atrium to the left atrium

the foramen ovale

what is the function of the dectus venosus

carries blood from the umbilical vein - to the liver - into inferior vena cava

what carries blood from the umbilical vein - to the liver - into inferior vena cava

ductus venosus

what do the umbilical arteries do

carry blood from the feus to the placenta

what carries blood from the feus to the placenta (paired)

umbilical arteries

what is a single vessel that carries blood from the placenta to the fetus

umbilical vein

where does teh gas, nutrition and waste exchange occur

at the placenta

name 3 things that hPL does

stimulates breast development supports fetal bone growth reduces insulin sensitivity to fetus

what is severe nausea from pregnancy

hyperemesis gravidarum

what is hyperemesis gravidarum

severe nausea from pregnancy