Study Questions 5-6

Question 1

What are the relationships between epiblast, ectoderm and epidermis?

Answer 1

epiblast is a tissue type derived from ICM or balstodisc, Epibast will develop from primitive ectoder. Epidermis is derived from ectoderm

Question 2

Which tissues are developing from the ectoderm

Answer 2

Epithelial and nervous tissue

Question 3

What is the neural plate and how is it formed

Answer 3

The neural plate is formed from the ectodermwhen it recieves specific signals from the mesoderm. It serves as a basis for the nervous system and the first step of neurulation

Question 4

Define neurulation

Answer 4

the process by which the neural plate forms a neural tube

Question 5

What are the four stages of primary neurulation in chick embryo

Answer 5

1. formation of neural plate, shapinga nd folding
2. shaping of neural plate, elevation
3. bending of neural plate to form neural groove, convergence
4. closure of neural groove to form the neural tube closure and detachment regulated by E and N cadherin switch

Question 6

What are the three primary vesicles formed during early brain development

Answer 6

forebrain, midbrain and hindbrain

Question 7

What are the five secondary vesicles formed during early brain development

Answer 7

telen cephalon, dien, mesen, meten, myelen

Question 8

What are the two major paracrine factors involved in dorsoventral polarization of the neural tube? Where do they originate from

Answer 8

The two major paracrine factors are:
notochord releases sonic hedgehog
ectoderm releases TGF-Beta

Question 9

What are cranial placodes and what is their position in respect to the neural plate

Answer 9

local and transient thickenings of ectoderm in the head and neck, they are beside the neural plate

Question 10

what are two examples of cranial placodes

Answer 10

olfactory placodes and otic placodes

Question 11

What are the five parts of the body that each somite is divided into

Answer 11

Slerotome- vertebrae
Myotome- back, ribs, limbs, abdominal wall
Dermatome- forms dermis of the back
Syndetome-tendons
Endothelial cells- cells thagt generate vascular cells in the dorsal cells

Question 12

How does the protein Notch influence gene expression

Answer 12

influences gene expression when it interacts with delta like 3 ligand on teh adjacent cell, and intracellular domain is cleaved and transcription occurs

Question 13

Do somites continue to exist n the body, or are the temporarily present in the embryo?

Answer 13

somites dont continue to exist because they are transient structures meaning they last only for a short time in the embryo to form bones, muscles and tissues

Question 14

What are the three distinct cell lineages involve din the formation fo the skeleton

Answer 14

1- cranial neural crest originated from the ectoderm
2- the somites of the paraxial mesoderm
3- somatic part of the lateral plate mesoderm

Question 15

what are the two models of bone formation

Answer 15

1. intramembranous ossification/direct ossificaion

2. Endochondal ossification/indirect ossification

Question 16

whats the difference between indirect and direct ossification

Answer 16

direct is the direct conversion of mesenchymal tissue to bone, and indirect is converted to cartilage and later replaced by bone

Question 17

distinguish between osteoblasts and osteoclasts

Answer 17

osteoclasts- break down bones, forms bone marrow by hollowing out internal bone
osteoblasts-build up bone, from bone matrix from partially degraded cartilage

Question 18

where does the intermediate mesoderm form? what organs will it develop into?

Answer 18

forms urogenital system and cortical portion of the adrenal glands . forms hte kidney, goands and teh duct systems

Question 19

Do early embryos use the same kidneys as later embryos

Answer 19

the embryo itself doesn’t use a kidney yet, relies on diffusion and blood vessel transportation to get rid of wastes