Lecture 15: Basic Body Plan Flashcards Preview

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Flashcards in Lecture 15: Basic Body Plan Deck (28):
1

notochordal process

cells of mesodermal layer migrate cranially down the midline to form the notochordal process, until it reaches the prechordal plate

2

function of notochord

primary inductor of the embryo
defines cranial caudal axis
formation of vertebral column
Induces overlying ectoderm to form neural plate

3

paraxial mesoderm

is found directly next to the notochord on either side, running down the same axis. Eventually gives rise to somites

4

Intermediate mesoderm

Immediately lateral to the paraxial mesoderm, gives rise to some of the urinary tract and reproductive system

5

Lateral Plate mesoderm

Lateral to intermediate mesoderm. has two parts, somatopleuric mesoderm and splanchopleuric mesoderm. The somatopleuric mesoderm is continuos with the extraembryonic mesoderm

6

Somatopleuric mesoderm

Gives rise to dermis, continuous with extra-embryonic mesoderm, top layer

7

splanchnopleuric mesoderm

Gives rise to walls of developing organs. associated with yolk sac, bottom layer

8

neurulation

Formation of neural tube

9

Neural Plate

The ectoderm overlying the notochord is induced by the notochord to thicken, creating neuro-ectoderm that makes up the neural plate

10

neural folds

Folds that grow up from neural plate on either side of neural groove. Eventually grow towards each other and join, forming neural tube

11

Fusion of neural folds

Happens in the mid-region and then migrates cranially and caudally.

12

neural crest cells

Present on the tips of the neural folds, and after fold fusion these cells are pinched off and migrate laterally and superficial to the neural tube

13

Neural tube migration

Dis-connects from ectoderm and migrates below into mesoderm

14

Neuropores

Present in anterior and posterior. Rostral closes day 24-25, caudal day 27. Not closing is called spina bifida

15

neural tube function

gives rise to CNS

16

neural crest cells function

gives rise to PNS, face muscles and bones, and adrenal medulla

17

cranial-caudal fold

Caused by very quick proliferation of neural tube cells at the cranial end to create forebrain/midbrain

18

Oropharyngeal membrane (prechordal plate)

Site of mouth

19

Cloacal membrane

site of anus

20

Somites

paired blocks of mesoderm that develop from paraxial mesoderm end of week 3. first appear cranially. By end of week 5 42-44 pairs

21

somite's function

give rise to skeletal muscles, dermis and axial skeleton

22

coelemic spaces

Form within lateral mesoderm and cardiogenic mesoderm, shapes coalesce into embryonic coelem

23

purpose of embryonic coelem

pericardial cavity, pleural cavity, peritoneal cavity

24

Angiogenesis begins when and where

Begins week 3
Begins
Extraembryonic mesoderm
Yolk sac
Connecting stalk
Chorion

25

angioblasts

mesenchymal cells in the yolk sac, which aggregate to form blood islands

26

blood vessel formation

small cavities form within blood islands, the angioblasts flatten to form endothelium, some endothelium breaks off and form red blood cells, cavities fuse to form vessels

27

heart tube

endocardial tubes arise from cardiogenic mesenchyme week 3, fuse to create heart tube. The heart tube fuses with vessels to create primitive cardiovascular system

28

Allantois

Out-pouching of yolk sac into connecting stalk, associated with development of bladder