Embryology (DAT)

After an egg has been ovulated from the ovary, it is called an

ovum

Prior to ovulation, when the egg is inside the ovary, it’s called an

oocyte

The most superficial layer of the ovulated ovum

corona radiata

The corona radiata forms ___ (before/during/after) ovulation

before

The layer of an ovulated ovum directly below the corona radiata

zona pellucida

Another name for the zona pellucida is the ___ membrane

vitelline

The zona pellucida is made of a thick translucent matrix of

glycoproteins

The zona pellucida contains ___ ___ proteins

sperm binding

The four sperm binding proteins are named

ZP1-4

This sperm binding protein ensures same species fertilization

ZP3

The layer below the zona pellucida of an ovulated ovum

perivitelline space

What anatomical part of an ovulated ovum prevents poly sperm

perivitelline space

The layer below the perivitelline space

plasma membrane

The acrosome of sperm are dervied from what organelle

golgi apparatus

The last required step for sperm to be mature enough to fertilize an ovum

capacitation

Capacitation removes the ___ coat that protects sperm from the acidic environment of the vagina

glycoprotein

Capacitation destabilizes the apical plasma membrane on the head of the sperm to expose the ___ so it can penetrate the egg

acrosome

Capacitation causes the sperm to become

hyperactivated

The name of the proteolytic enzyme found in the acrosome which can penetrate the zona pellucida

acrosin

Fertilization triggers completion of ___ in the egg

meiosis II

Fertilization is responsible for the determination of

gender

If a sperm is carrying the X chromosome, the zygote is a

female

If a sperm is carrying the Y chromosome, the zygote is a

male

Multiple sperm fussing with an ovum

polysperm

Polysperm is prevented by what two methods

fast block and slow block

When the sperm fuses with the plasma membrane of an egg, sodium channels open and sodium flows ___ (into/out of) the egg

into

In a fast block, when the sperm fuses with the plasma membrane of an egg, ___ occurs, thus blocking other sperm from fusing with the membrane also

depolarization

The fast block to prevent polyspermy is ___ (short/long) lasting

short

The slow block to prevent polyspermy is ___ (short/long) lasting

long

The slow block occurs ___ (before/during/after) the fast block

after

The depolarization caused by the fast block causes the ER to release what ion

calcium

The calcium that is released from the ER of egg cells after the fast block causes a ___ reaction

cortical

In the cortical reaction, a fertilization envelope forms due to an enlarged

perivitelline space

In the cortical reaction, the enlarged perivitelline space deactivates the

ZP receptors

Rapid cell division without cell growth

cleavage

The resulting cells that are formed from cleavage from a fertilized ovum

blastomere

indentation on the surface of the cell when it begins to divide and pinch off

furrow

What type of cleavage occurs when the cleavage furrow completely separates the cell into two equal blastomeres

holoblastic

What type of cleavage occurs when the cell undergoes partial unequal cleavage that results in different sized blastomeres

meroblastic

The factor that determines what type of cleavage a cell will undergo

yolk

Holoblastic cleavage occurs when there is ___ (low/high) amounts of yolk

low

Meroblastic cleavage occurs when there is ___ (low/high) amounts of yolk

high

When a cell decides what it will be in the future—what genes it will express and what genes it will suppress

determination

When a cell physically looks different because of the expressed genes

differentiation

Determination happens ___ (before/during/after) differentiation

before

What type of cleavage occurs if the cells have decided what genes they are going to express

determinant

What type of cleavage occurs if the cells have not decided what genes they are going to express

indeterminant

The pole of an egg that has more yolk

vegetal

The pole of an egg that has less yolk

animal pole

Which pole of an egg is slow at dividing

vegetal

What pole of an egg is fast at dividing

animal

The embryo grows in which pole of an egg

animal

The axis that divides the vegetal pole from the animal pole of an egg is called the ___ axis

polar

What type of cleavage occurs if the cleavage furrow is parallel or perpendicular to the original polar axis

radial cleavage

What type of cleavage occurs if the cleavage furrow has no pattern of alignment to the polar axis

spiral cleavage

Spiral cleavage results in uneven blastomeres called ___ and ___

macromeres and micromeres

What type(s) of cleavage do protostomes undergo

determinant, spiral

What type(s) of cleavage do deuterostomes undergo

indeterminant, radial

All cleavage happens within the

zona pellucida

The zona pellucida also serves as a ___ barrier for the developing egg

immune

A zygote is eventually called a

morula

A solid ball of cells that has between 16 and 32 blastomeres

morula

The morula eventually become a

blastula

The morula become a blastula in a process called

blastulation

After blastulation a human is called a

blastocyst

When the morula form a spherical ring along the zona pellucida, a hollow cavity is created called a

blastocoel

After blastulation, ___ occurs

gastulation

The cells of the blastula invaginate in an inward folding motion, pushing themselves into the blastoceal

gastrula

When the gastrula begins to form and the first cells of the blastula fold inward, that fold is called a

blastopore

The blastopore eventually becomes the ___ or ___

mouth or anus

If the blastopore forms the mouth first, the animal is a

protostome

If the blastopore forms the anus first, the animal is a

deuterostome

Once the blastopore invaginates itself the entire way through the egg, an ___ is formed

archenteron

The ectoderm is the ___ (interior/middle/exterior) layer

exterior

The mesoderm is the ___ (interior/middle/exterior) layer

middle

The endoderm is the ___ (interior/middle/exterior) layer

interior

In humans, blastocysts differentiate into ___ and ___

trophoblast and embryoblasts

Another name for embryoblasts

inner cell mass

Cells on the exterior of human blastocysts which give rise to the placenta

trophoblast

Another name for the placenta

chorion

The cell responsible for implantation

trophoblast

The process when the egg is inserted into the endometrium of the uterus

implantation

The name of the process where the trophoblast breaks free of the zona pellucida

zona hatching

hCG is the hormone produced by what embryonic cell

trophoblast

The ICM gives rise to what four things

embryo, ammion, yolk sac, allantois

List the two cell types of the ICM which are arranged as single layered sheets right on top of one another

epiblast and hypoblast

Top layer of the ICM

epiblast

Bottom layer of the ICM

hypoblast

The epiblast and the hypoblast make up the ___ disc

bilaminar

The top epiblast layer will form a cavity called the

ammion

When gastrulation occurs in humans at the epiblast layer, it widens and forms a ___ streak with a groove

primistine

The prime animal used for amphibian embryonic development

frog

Frog eggs are fertilized ___ (on land/in water)

in water

Frogs undergo ___ (holoblastic/meroblastic) cleavage

holoblastic

Humans undergo ___ (holoblastic/meroblastic) cleavage

holoblastic

When a frog sperm fuses with a frog egg, it always occurs at the ___ pole

animal

After the frog sperm and egg fuse, the cytoplasm rotates 30º to form the

gray crescent

The point exactly opposite from where the frog sperm fused with the egg

gray crescent

The orientation of the frog embryo ___ (changes/does not change) as it develops

does not change

At the point when a frog embryo consists of thousands of cells and has a hollow cavity, it is called a

blastula