Lecture 24: Gastrulation Flashcards

1
Q

gastrulation

A

formation of the endoderm, mesoderm, and ectoderm from epiblast and hypoblast, axes development also occurs at this time

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2
Q

ingression

A

movement of cells from the outside to the inside of the embryo, AKA epithelial to mesenchymal transformation

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3
Q

invagination

A

cells fold inward

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4
Q

involution

A

cells folding over each other

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5
Q

spreading/convergent extension

A

cells move into a narrow line, helps lengthen the tissue, move it forward, or form tubular structures, process occurs via cell surface lampellipodia

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6
Q

bilaminar disc

A

contains an epiblast and hypoblast layer, also has buccopharyngeal membrane and cloacal membrane

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7
Q

buccopharyngeal membrane

A

forms into mouth

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8
Q

cloacal membrane

A

forms into anus

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9
Q

gastrulation process

A

1.) cells from epiderm ingress through primitive streak to form the definitive endoderm 2.) ingresssing cells replace the hypoblast 3.) once suffice definitive endoderm cells have ingressed, the ingressing cells form the mesoderm 4.) mesodermal cells migrate via spreading convergent extension after leaving the primitive streak 5.) cells with different cranial/caudal positions who leave the primitive streaks have different fates

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10
Q

hyaluronic acid

A

prevents mesodermal cells from clumping together

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11
Q

morphogenesis

A

process by which tissue and organs form

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12
Q

ectoderm

A

skin and nervous system

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13
Q

mesoderm

A

muscle, bone, blood

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14
Q

endoderm

A

guts, lungs, liver, pancreas

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15
Q

differentiation

A

occurs at the level of CELLS (process by which cells take on their separate identity)

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16
Q

morphogenesis

A

occurs at the level of TISSUES (process the gives rise to the shape and form of tissue and organs)

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17
Q

ingression

A

involves the movment of single cells away from a surface layer into the interior of the embryo

18
Q

germ disk

A

embryonic stage around 2 weeks that consists of the epiblast (blue) and hypoblast (yellow); bilaminar aka two layer disk

19
Q

buccopharngyal membrane

A

form the mouth and oral cavity at the cranial (head) region of the embryo

20
Q

cloacal membrane

A

region where epiblast and hypoblast fuse to form the anus at the caudal end of the embryo

21
Q

primitive groove

A

the furrow extending the length of the streak

22
Q

primitive node

A

raised circle of cells at the cranial end

23
Q

primitive pit

A

depression in the center of the primitive node

24
Q

extraembryonic mesoderm

A

forms prior to gastrulation and forms the amnion, chorion, and yolk sac

25
Q

embryonic mesoderm

A

forms the embryo proper as a result of gastrulation

26
Q

process of gastrulation

A

The epiblast cells will first ingress form endoderm, with subsequent ingression and spreading to fill in and form mesoderm

27
Q

hyaluronic acid

A

Epiblast cells will secrete hyaluronic acid into the space between the ectoderm and endoderm, which is important to prevent mesoderm from aggregating

28
Q

fibronectin

A

on the basal side of the ectoderm help mesoderm to migrate

29
Q

cilia

A

on ectoderm near the primitive node help the mesoderm cells to migrate

30
Q

Kartagener’s syndrome

A

cilia on the ectoderm near the primitive node cannot form the proper current necessary for the distribution of intercellular molecules. Dysfunction dynein arms on the cilia will present this syndrome.Leads to situs inverstus of embryonic lethality

31
Q

Cells that move CRANIAL from the primitive node form:

A

Prechordal plate and notochord

32
Q

prechordal plate

A

thickening of hypoblast and mostly mesoderm rostral to the notochord, crictical for formation of forebrain

33
Q

notochord process

A

extends caudally from prechordal plate and primitive streak regresses simultaneously

34
Q

notochordal plate

A

the notochord process fuses with the

definitive endoderm for about a day

35
Q

neurenteric canal

A

one side of the
notochordal plate is exposed to the fluid of the definitive yolk sack while the other
side sees cells

36
Q

notochord

A

tissue then involutes and lifts off the endoderm to form a column of cells, no cells like notochord process

37
Q

neural plate

A

prechordal plate and notochord will induce overlying ectoderm on the dorsal side to become neural precursor cells

38
Q

neural tube

A

prechordal plate and notochord signal overlying ectoderm to invaginate to form neural grooves and neural folds, eventually forms neural tube, which is the basis for the spinal chord neural groove forms basis for neural tube

39
Q

extracellular matrix induction

A

one cell touches another indirectly through extracellular matrix, causing integrins in the affected cell to become active.

40
Q

direct cell induction

A

the cells are directly touching each other

41
Q

diffusion of a morphogen

A

secreted morphogen from one cell is picked up by another