Paraxial and Intermediate Mesoderm

Question 1

what are the 4 specific regions of the mesoderm?

Answer 1

1. notochord
2. somitic(paraxial) mesoderm
3. intermediate mesoderm
4. lateral plate mesoderm

Question 2

the notochord is AKA the

Answer 2

chordamesoderm

Question 3

notochord formation is induced along with the

Answer 3

neural tube

Question 4

what type of mesoderm is found on either side of the neural tube?

Answer 4

somitic (paraxial)

Question 5

the intermediate mesoderm forms the

Answer 5

urogenital system

Question 6

lateral plate mesoderm forms

Answer 6

• heart
• blood vessels
• blood cells
• parietal linings of body cavities

Question 7

during neurulation, somites begin to form from the

Answer 7

paraxial mesoderm

Question 8

list the 4 specifications & differentiations of somites

(somite divisions)

Answer 8

1. sclerotome
2. myotome
3. dermatome
4. syndetome

Question 9

the specification & differentiation of somites occurs from

Answer 9

messenchymal stem cells within the somite

Question 10

somitogenesis is the

Answer 10

formation of somites simultaneously on each side of the neural tube

Question 11

approximately how many days post-fertilization does formation of somites begin?

Answer 11

20-30 days

Question 12

what determines the specific location of somite formation? where else was this seen?

Answer 12

• notch signaling
• seen in juxtacrine attachment of cells

Question 13

components of somitogenesis involves the

Answer 13

“clock and wave mechanism”

Question 14

what is the order of the process of the components of somitogenesis?

Answer 14

1. periodicity
2. fissure formation
3. epithelialization
4. specification & differentiation

Question 15

periodicity refers to the “____________________” for the formation of _______.

Answer 15

“time pattern”

somites

Question 16

fissure formation is the

Answer 16

separation of individual somites from each other

Question 17

fissure formation requires….
why?

Answer 17

• tyrosine kinases
• to ensure proper separation

Question 18

epithelialization occurs after somite fission when messenchymal cells produce

Answer 18

epithelial covering around somites w/ fibronectin & cadherin

for adhesion

Question 19

specification & differentiation refers to when

Answer 19

expressed gene segments within the somites form specific structures

Question 20

paracrine factors are

Answer 20

inducing factors from the notochord and neural tube

Question 21

paracrine factors stimulate the commitment of somites into

Answer 21

• sclerotome
• dermatome
• myotome

Question 22

following somite stimulation the notochord undergoes

Answer 22

apoptosis

Question 23

after the notochord undergoes apoptosis the remaining notochord cells form a portion of the

Answer 23

vertebral disc

Question 24

in myogenesis paracrine factors induce

Answer 24

myotome formation from the somites

Question 25

what protein is involved in myogenesis?

Answer 25

MyoD

Question 26

the specific protein MyoD induces the

Answer 26

synthesis of muscles from expressed muscle specific genes

Question 27

muscle formation relies on

Answer 27

- cadherins for attachment - Ca 2+ for development & contraction

Question 28

messenchymal cells are

Answer 28

stem cells which form all connective tissues

Question 29

connective tissue converts to bone by

Answer 29

intramembranous ossification

Question 30

connective tissue converts to cartilage from

Answer 30

chondrocytes

Question 31

chondrocytes serve as the skeletal template for.... what is this known as?

Answer 31

bone formation endochondral ossification

Question 32

endochondral ossification forms what structures

Answer 32

- vertebral column - ribs - pelvis - long bones - limbs