week 7 lectures (neural tube)

Question 1

when the fertilised egg divides what does it become?

Answer 1

first the cleave

then the blastocyst which is a hollow sphere

Question 2

what happens to the blastocyst when it implants into the uterus?

Answer 2

it forms a two layered embryonic disk

Question 3

what are the two layers of the embryonic disk?

Answer 3

the epiblast

the hypoblast

Question 4

what structure in the embronic disk gives rise to gastrulation?

Answer 4

the primitive streak

Question 5

what is gastrulation?

Answer 5

tranformation of the two layered disk into 3 germ layers: ectoderm, mesoderm and endoderm

Question 6

what causes the embryonic stem cells to differentiate into neurons?

Answer 6

cells migrate inwards through the primitive streak and some up towards the primitive node

the primitive node secretes cellular signals that turn the embryonic stem cells into neurons

Question 7

what is the primitive node called in birds?

Answer 7

hansens node

Question 8

what is the primitive node called in amphibians?

Answer 8

spemman mangold organiser

Question 9

what does the endoderm go on to form?

Answer 9

the lining of internal organs (viscera)

Question 10

what does the ectoderm go on to form?

Answer 10

the skin and the nervous system

Question 11

what does the mesoderm go on to form?

Answer 11

bones and muscles

Question 12

what happens at week 4-5 of foetal development?

Answer 12

embryo recognisable with a head

‘tailbud stage’

Question 13

what happens at week 4-8 of foetal development?

Answer 13

the embryonic stage

organogenesis occurs

main tissue and organ systems develop

major features of body form develop

Question 14

what happens from the 3rd month till birth

Answer 14

foetal period

maturation of tissues and organs

rapid growth of the body

cell proliferation