embryogenesis 3

Question 1

how is the avitation formed in the molura

Answer 1

sodium is pumped into centre and osmotic pressure forms the blastomere

Question 2

what is the bilaminar disc

Answer 2

the innner cell of the blstocyte differentiate to form two layers - epiblast and hypoblast

Question 3

what is the hypoblast

Answer 3

deep layer of the bilaminar disc which will form the yolk sac

Question 4

what is the epibast

Answer 4

superficial bilaminar disc cells, forms embryonic body

Question 5

what is gastrulation

Answer 5

process when the trilaminar disc forms (the top cells migrate to the center creating dpression - primative streak

Question 6

list the layers of the trilaminar disc

Answer 6

Ectoderm
Mesoderm
Endoderm

Question 7

what does the ectoderm layer give rise to in the adult

Answer 7

epidermis of skin, hair, mout and nose, nervous system and skin of glands

Question 8

what does the mesoderm layer give rise to in the adult

Answer 8

dermis of skin, muscle, skelton, vascular, gonads, kidneys, digestive (outerlayer) and respritory

Question 9

what does the endoderm layer give rise to in the adult

Answer 9

digestive inner, respritory, liver and pancrease

Question 10

what is polarisation and why is it important

Answer 10

creation of two signaling areas which will provide a linear development line. cruical proper development

Question 11

When the axis is not properly developed, what happens

Answer 11

abnormal growth , extra limb, missed organs or sever asymetry

Question 12

polorisation of the body

Answer 12

node

Question 13

polarisation of the head

Answer 13

AVE Anterior visceral endoderm

Question 14

how does the bird deveplop polarity

Answer 14

using gravity

Question 15

how does twinning occur

Answer 15

Loss or asymmetry can result in twins (monozygotic, identical)
Implantation fo more than one embryo (dizygotic, not identical)

Question 16

why is left and right asymetry cruical for development

Answer 16

internal organs are asymetrical (consider the heart on left side and differing lung size, this is essecially applicalbe to small channels in the body, respitroy or vascular. if they are made symetrical the body will faill

Question 17

describe the importance of timing in monozygotic twins

Answer 17

timming of the spit leads to likleyhood of a succsessfull offspring. earlyt twinning, leads to proper placental membrane formation. late twining leads to resource supply competition.