Lab3

Question 1

Cleavage

Answer 1

Phase of development in which an embryo’s cells rapidly undergo mitosis with little or no cell growth.

Question 2

Meroblastic cleavage

Answer 2

cleavage in which the daughter cells seperate incompletely.

Question 3

Discoidal cleavage

Answer 3

Cleavage occurs only in the blastodisc.

Question 4

Blastoderm

Answer 4

In fish and birds, the multicellular structure that forms when the blastodisc undergoes cleavage.

Question 5

Area opaca

Answer 5

Dark-staining region of the avian blastoderm that lies directly over the yolk, and surrounds the area pellucida.

Question 6

Area opaca Vasculosa

Answer 6

Inner region of area opaca.

Question 7

Area opaca Vitellina

Answer 7

Outer region of area opaca.

Question 8

Epiblast

Answer 8

In birds and mammals, the upper or surface layer of the blastoderm.

Question 9

Hypoblast

Answer 9

In birds and mammals, the lower or inner layer of the blastoderm.

Question 10

Subgerminal cavity

Answer 10

A space that lies between the yolk and blastoderm of early chick embryos.

Question 11

Koller’s sickle

Answer 11

In avian gastrulation, Koller’s sickle is a local thickening of cells at the posterior edge of the upper layer of the epiblast.

Question 12

Primitive streak

Answer 12

A longitudinal thickening of the epiblast through which cells ingress.

Question 13

Primitive groove

Answer 13

Longitudinal depression in the primitive streak through which cells ingress.

Question 14

Primitive folds(ridge)

Answer 14

Paired raised edges of primitive streak.

Question 15

Primitive pit

Answer 15

Depression in primitive knot that is continuous with the primitive groove.

Question 16

Henson’s node(primitive knot)

Answer 16

Cranial thickening of primitive streak.

Question 17

Proamnion

Answer 17

A lightly staining, crescent-shaped region of the area pellcida cranial to the developing head of early chick embryo.

Question 18

Head fold

Answer 18

A ventrally-directed body fold of an early embryo that outlines the head region.

Question 19

Head process

Answer 19

A longitudinal band of mesoderm cells.

Question 20

Notochord

Answer 20

A longitudinal, rod-like structure that runs the length of the dorsal embryonic axis between digestive and neural tube.

Question 21

Neural plate

Answer 21

Thickened ectoderm that is the earliest rudiment of the central nervous system.

Question 22

Head mesenchyme

Answer 22

Loosely arranged cells found between brain and skin ectoderm of head.

Question 23

Subcephalic pocket

Answer 23

A space under the head of the chick embryo.

Question 24

Cranial intestinal portal

Answer 24

Opening of foregut into midgut in amniotes.

Question 25

Foregut

Answer 25

Cranial region of the embryonic gut that extends from the head to midgut.

Question 26

Prechordal plate

Answer 26

Thickening in the endodermal layer.

Question 27

Oral membrane(plate)

Answer 27

A double-layered sheet of ectoderm and endoderm that seperates the foregut and stomodeum.

Question 28

Mesoderm

Answer 28

Middle embryonic germ layer between ectoderm and endoderm.

Question 29

Axial mesoderm

Answer 29

Lies central axis under neural tube, gives rise to notochord.

Question 30

Paraxial mesoderm or Segmental plate or Somitic mesoderm

Answer 30

Lies to the left and right sides of neural tube that gives rise to somites.

Question 31

Somitomere or somite

Answer 31

Paired blocks of paraxial mesoderm.

Question 32

Coelom

Answer 32

Cavity of the embryo.

Question 33

Somatopleure

Answer 33

A layer made of surface ectoderm and somatic mesoderm.

Question 34

Ectoderm

Answer 34

Outermost embryonic germ layer that forms during gastrulation.

Question 35

Splanchnopleure

Answer 35

A layer made of splanchnic mesoderm and endoderm.

Question 36

Endoderm

Answer 36

Innermost embryonci germ layer that forms during gastrulation.

Question 37

Splanchnic mesoderm

Answer 37

The ventral layer of lateral plate mesoderm.

Question 38

Heart rudiment

Answer 38

Cone like structure that is formed when myocardial progenitor cells of heart fuse at midline.

Question 39

Cardiac primordium

Answer 39

Aggregation of angioblastic cells in cardiogenic region.

Question 40

Pericardial cavity rudiment

Answer 40

Portion of coelom that houses the heart.

Question 41

Vitelline vein

Answer 41

Paired veins that drain blood and nurients from yolk sac into ductus venosus.