Embryology week 3

Question 1

The first major event of the third week (about 16 days) is called what?

Answer 1

Gastrulation

Question 2

Gastrulation starts with the formation of a longitudinal midline structure called what? What end is it near?

Answer 2

Primitive streak

Caudal end of the bilaminar embryonic disc

Question 3

The cranial end of the primitive streak is expanding and is called what?

Answer 3

primitive node

Question 4

The primitive streak also contain a circular depression called the ________, and it leads to a trough like depression called _________.

Answer 4

primitive pit

primitive groove

Question 5

What color is endoderm?

Answer 5

yellow

Question 6

What color is mesoderm?

Answer 6

red

Question 7

What color is ectoderm?

Answer 7

blue

Question 8

True/False: the primitive pit and groove are areas where cells are leaving the primitive streak and entering the interior of the embryonic disc.

Answer 8

True

Question 9

What does the precordal plate form?

Answer 9

mouth

Question 10

Cardiogenic mesoderm forms what?

Answer 10

heart

Question 11

What is the order of migration from cranial to caudal?

Answer 11

Notochord
Head mesoderm
somites
intermediate mesoderm
lateral plate mesoderm

Question 12

What is the future vertebrae?

Answer 12

notochord

Question 13

What is the origin of notochord? (IMPORTANT)

Answer 13

mesoderm

Question 14

IN the future head region the mesoderm forms bands of cells that remain ________ as the head mesoderm.

Answer 14

unsegmented

Question 15

The head mesoderm eventually gives rise to the striated muscles of the _________________.

Answer 15

Face, jaw, and throat

Question 16

A loosely organized, mainly mesodermal embryonic tissue that develops into connective and skeletal tissues, including blood and lymph.

Answer 16

Mesenchyme

Question 17

What are block-like condensations of mesoderm?

Answer 17

somites

Question 18

Th caudal most several somites eventually disappear, why? How many somite pairs are left?

Answer 18

because we don’t have a tail

37 pairs

Question 19

Is head mesoderm above or below somites?

Answer 19

above, towards cranial end

Question 20

Somites form what important structures?

Answer 20

vertebral column, occipital bone, voluntary musculature of the neck, body wall, limbs, etc.

Question 21

What does the lateral plate mesoderm split into?

Answer 21

parietal (somatic) layer with overlying ectoderm

visceral (splanchnic) layer

Question 22

Formation of the neural tube which is the beginning of the neural system?

Answer 22

Neuralation

Question 23

Neurulation involves four main events called what:

Answer 23

Formation of the neural plate
shaping of the neural plate
bending of the neural plate
closure of the neural groove

Question 24

True/False: Notochord is on the surface of the Neural plate.

Answer 24

False, notochord is underneath the neural plate

Question 25

What is happening at days 18, 19 and 20?

Answer 25

Neuralation, making the brain

Question 26

What is another word for a triggering event?

Answer 26

inductive event

Question 27

Anything above the somite is going to be what part of your body?

Answer 27

head

Question 28

What are two types of ectoderm?

Answer 28

neural ectoderm

surface ectoderm

Question 29

the blastocyst contains which 2 parts?

Answer 29

inner cell mass (ICM) and the trophoblast