Vertebrate Development : Life cycles and experimental techniques

Question 1

Antero-posterior axis

Answer 1

Main body axis of vertebrates

Question 2

Somites

Answer 2

somite is a division of the body of an animal or embryo, are bilaterally paired blocks of paraxial mesoderm that form along the head-to-tail axis of the developing embryo in segmented animals

Question 3

Cleavage

Answer 3

rapid cell divisions by which the embryo becomes divided into a number of smaller cells

Question 4

Gastrulation

Answer 4

Set of cell movements that generates the three germ layers, ectoderm, mesoderm, and endoderm

Question 5

Phylotypic stage

Answer 5

Stage of the embryo when the neural tube, somites, notochord, and head structures are present

Question 6

Notochord

Answer 6

transient stiff, rod-like cellular structure in vertebrate embryos that runs from head to tail and lies centrally beneath the neural tube. It is derived from mesoderm and its cells eventually become incorporated into the vertebral column

Question 7

Axial Structures in Vertebrates

Answer 7

notochord, neural tube, somites and vertebral column

Question 8

What eventually happens the cells of the Notochord?

Answer 8

They are incorporated into the vertebral column that forms the spine

Question 9

From which germ layer do somites develop?

Answer 9

Mesoderm

Question 10

What major differences in development are there between the 5 main model organisms (zebra fish, xenopus, mouse, chick, human)

Answer 10

How and when axis are set up and how germ layers are established

Question 11

What is the main reason for the differences in embryonic development across model organisms

Answer 11

differing modes of reproduction and the consequent form of the early embryo

Question 12

Extra-embryonic membranes

Answer 12

membranes external to the embryo proper that are involved in its protection and nutrition, In mammals they include the amnion, chorion, and placental tissues

Question 13

Amniotes

Answer 13

Organisms such as birds and mammals that form the amniotic extra-embryonic membrane

Question 14

Anamniotes

Answer 14

Organisms such as fish and amphibians that do not form the extra-embryonic membranes

Question 15

How are the stages of Development classified?

Answer 15

By the development of main features rather than by time after fertilization

Question 16

What is the great advantage to using Xenopus as a Model Organsim?

Answer 16

Fertilized eggs are easy to obtain

Question 17

Animal Region

Answer 17

In eggs of amphibians, the hemispherical end of the egg where the nucleus resides, away from the yolk. The most terminal part of this region is the animal pole, which id directly opposite the vegetal pole at the other end of the egg

Question 18

Animal Cap

Answer 18

The pigmented animal half of the Animal Region of Xenopus

Question 19

Animal-Vegetal axis

Answer 19

Axis that runs from the animal pole to the vegetal pole

Question 20

Blastomeres

Answer 20

Cells deriving from cleavage divisions

Question 21

In which half of the Xenopus embryo is cleavage slower?

Answer 21

Yolky Vegetal Half

Question 22

Marginal Zone

Answer 22

Belt like region of presumptive mesoderm at the equator of the late blastula of an amphibian embryo. Gives rise to the Mesoderm

Question 23

Which region gives rise to the endoderm in Xenopus?

Answer 23

Vegetal Region

Question 24

Which region gives rise to the ectoderm in Xenopus?

Answer 24

Animal Region

Question 25

What is the first sign of Gastrulation?

Answer 25

Development of a small slit-like infolding blastopore on the surface of the blastula on the future dorsal side

Question 26

Archenteron

Answer 26

precursor of the gut cavity