vertebrate development

Question 1

stages of embryotic development

Answer 1

cleavage, blastula formation, gastrulation, neurulation

Question 2

cleavage (frog)

Answer 2

rapid division of the zygote into a MORULA (solid ball of cells)

*** more rapid in animal pole

Question 3

animal vs vegetal pole

Answer 3

more yolk in vegetal, slower division

Question 4

blastula (frog)

Answer 4

hollow ball of cells

Question 5

blastula formation (frog)

Answer 5

continued division to form blastula (with blastocoel inside)

Question 6

gastrulation (frog)

Answer 6

cells from outer surface migrate in through blastopore, displacing the blastocoel and forming the archanteron.

3 embryonic germ layers are established - eventually outside lined by ectoderm, archanteron lined with endoderm, and other is mesoderm

medial region of the mesoderm gives rise to the notochord, on the dorsal midline of the embryo

Question 7

mesoderm generally gives rise to

Answer 7

many regions of the skeleton, most muscles, notochord, circulatory system

Question 8

endoderm generally gives rise to

Answer 8

lining of the digestive tract as well as liver, pancreas, gall bladder, digetive glands, lungs, swim bladder, and urinary bladder

Question 9

ectoderm generally gives rise to

Answer 9

epidermis and many skin glands, as well as nervous system and many sensory organs

Question 10

neural plate formation (frog)

Answer 10

notochord signals for ectoderm dorsal to notochord to differentiate into neural plate ectoderm

Question 11

neurulation (frog)

Answer 11

neural plate ectoderm bends, forming neural groove surrounded by neural folds

folds fuse into hollow neural tube (inside is neurocoel), gives rise to central nervous system

neural crest cells from dorsal region of tube (what was connecting to neural plate ectoderm) separate, become mesenchymal

Question 12

differentiation of mesoderm

Answer 12

AFTER gastrulation, meso diff into EPIMERE, MESOMERE, HYPOMERE

Question 13

epimere mesoderm forms___ and differentiates into ____

Answer 13

somites

dermatome (most dorsal), myotome (my how far from midline), sclerotome (sneakily close to notochord)

Question 14

hypomere mesoderm is located where in the embryo (frog)

Answer 14

to the right and left of the archanteron

Question 15

coelom - how does it form and what is it?

Answer 15

two spaces which give rise to the major body cavities in adults

the hypomere mesoderm to the right and left of the archanteron differentiate into somatic on the outside, splanchnic on the inside and the space between them is the coelom

Question 16

microlecithal eggs

Answer 16

little yolk

Question 17

mesolecithal eggs

Answer 17

medium yolk

Question 18

macrolecithal eggs

Answer 18

large yolk

Question 19

early development in birds

Answer 19

cleavage at small region of animal pole, forming a BLASTODISC

cells in disc differentiate into top - EPIBLAST, and bottom - HYPOBLAST, with blastocoel between

Question 20

blastodisc

Answer 20

flat disc of cells

Question 21

epiblast

Answer 21

top part of differentiated blastodisc

Question 22

hypoblast

Answer 22

bottom part of differentiated blastodisc

Question 23

gastrulation in birds

Answer 23

epiblast (top) cells migrate towards the primitive streak , 3 germ layers are derived from the epiblast

mesodermal cells to middle, endodermal cells displace the hypoblast (hypoblast guides)

Question 24

neurulation in birds

Answer 24

now embryo w/ three layers, ectoderm on top, mesoderm in middle split by notochord, endoderm on bottom on yolk surface

noto signals diff of ecto into neural plate ectoderm, folds into neural groove w/ neural folds on each side, fuse to form neural tube

neural crest cells separate from the dorsal region of the neural tube

Question 25

development of the central nervous system

Answer 25

anterior of neural tube swells into brane, posterior to head gives rise to spinal cord

Question 26

differentiation of mesoderm into 3 regions

Answer 26

epimere (SUPER CLOSE TO NOTO, mesomere(mid close to noto), hypomere (super far from noto)

Question 27

differentiation of epimere mesoderm

Answer 27

forms somites in trunk region which differentiate into myotome, dermatome, and sclerotome

Question 28

formation of the coelom

Answer 28

hypomere mesoderm differentiates into somatic (top) and splanchnic (bottom) mesoderm, space in between is the coelom

Question 29

digestive system formation in chicks

Answer 29

***** in frogs gastrulation ends, then neurulation vs in chicks, gastrulation is still happening during neurulation endoderm invaginates to form early gut

Question 30

what are the 4 extra embryonic membranes what do amniotes have?

Answer 30

amnion, chorion, allantois, yolk sac only amniotes have an amnion, chorion, and allantois many INCLUDING amniotes produce a yolk sac

Question 31

what are amnion and chorion from

Answer 31

somatopleure - ectoderm and somatic hypomere mesoderm (top layer of embryo , not aroud the neural tube etc

Question 32

what are the yolk sac and allantois from?

Answer 32

splanchnopleure - endoderm and splanchnic hypomere mesoderm (bottom of embryo by yolk)

Question 33

allantois function

Answer 33

sequesters nitrogenous metabolic wastes

Question 34

yolk sac function

Answer 34

surrounds the yolk and forms vitelline vessels vessels generally formed by splanchnic hypomere mesoderm

Question 35

amnion function

Answer 35

waterproof, and surrounds the embryo with amniotic fluid

Question 36

chorion function

Answer 36

outermost membrane fuses with outer section of the allantois to form chorioallantoic membrane this contains allantoic vessals from splanchnic hypomere mesoderm used to exchange gases w/ environment through shell, transport calcium from shell to embryo

Question 37

specific roles of extra-embryonic membranes in mammals

Answer 37

choreoallantoic membrane and/or yolk sac prod the umbilical cord and embryonic region of the placenta amnion surrounds embryo in a fluid filled capsule

Question 38

benefits of amniotic sac

Answer 38

control of proteins reaching embryo protection from pathogens cusioning from mechanical impact temperature regulation room for embryo to grow and move prevents dessication (drying out) provides support by letting embryo float as skeletal system develops