Development II

Question 1

cleavage

Answer 1

cels divide very rapidlly w no time for growth so cell = v small; rate of cell division slows down

Question 2

morphogenesis

Answer 2

change of shape of an organism; cellular + tissue based processes so animal body will take shape; occurs in last 2 stages of embryonic dev = gastrulation and organogenesis

Question 3

gastrulation

Answer 3

morphological process; gastula w embryonic germ layers

Question 4

morphological process of gastrulation

Answer 4

hollow ball of blastomeres undergos gastrulation to morph into layers embryo (gastrula)

Question 5

gastrula

Answer 5

embryonic germ layers: ectoderm, endoderm, mesoderm

Question 6

ectoderm

Answer 6

outer layer

Question 7

endoderm

Answer 7

lines embryonic digestive tact/cavity

Question 8

mesoderm

Answer 8

btwn ecto and endo

Question 9

diploblasts

Answer 9

only endo and ect; ex: radial sym orgs (cnidarians)

Question 10

triploblasts

Answer 10

all 3 germ layers dev; vert and bilaterally sym orgs

Question 11

sea urch gastrulation

Answer 11

cell migration; invagination; 2nd opening develops into mout (deuterostomes); archenteron dev from invag + becomes deeps, narrows dev blind ended tube future digestive tract/gut of org; blastopore - open end of archenteron dev into anus

Question 12

cell migration

Answer 12

during gastrulation cells move w/i dev gastrula; local cellular interactions via long distance migration

Question 13

invagination

Answer 13

folding inwards; infolding of a sheet of cells into embryo

Question 14

sea urch gast seq of events

Answer 14

(1) vegetal pole w mesenchyme cell undergoes cell mig into blastocoel some will later secrete CaCO3, forms simple internal skeleton (2) at veg pole other cell slighten fallten and cause VP to buckle inwards invag into embryo (3) endoderm cells form archenteron (future DT) (4) blastopore (open end = anus) fuses w blastocoel wall, site of fusion dev mouth opening and creates complete dig tube w both mouth + anus

Question 15

mesenchyme cell in sea urch gast

Answer 15

at tip of archenteron produce filopodia that eventually contract and drag archenteron across blastocoel

Question 16

filopodia

Answer 16

thin cell extensions that extend toward blastocoel wall

Question 17

frog gastrulation

Answer 17

verts w 3 germ layers; blastopore - open end of archenteron dev into anus; frog and other bilater verts w dorsal, venral, posterior, R/L, anterior all arise and dev during gastrulation; cells move to begin gastrulation

Question 18

chick gastrulation

Answer 18

lots of yolk presence so simple gatrulation can’t happen at vegetal hemi; 2 layered embryo (hypoblast, epiblast) at beginning of gast w both on top of yolk mass; primitive streak

Question 19

hypoblast

Answer 19

lower layer; directly on top of yolk mass

Question 20

epiblast

Answer 20

upper layer; contains cells that form the embryo proper

Question 21

primitive streak fate

Answer 21

some cells move downward toward yolk mass and push hypoblast cells arise to form endoderm; other cells migrate laterally to form mesoderm

Question 22

organogenesis

Answer 22

organ formation while increasing embryo size; neurolation

Question 23

neurolation

Answer 23

cells from dorsal mesoderm form notochord; induction; neural plat; neural tube

Question 24

notochord

Answer 24

flexible, longitudial rod; internal skeleton of embryo

Question 25

induction

Answer 25

certain cells will stimulate/influence differentiation of neighboring cells; developing notochord induce neighboring overing ectoderm which thickens to form neural plate

Question 26

neural tube defects

Answer 26

ancephaly - no forebrain; spina bifia; due to folic acid deficiency

Question 27

neural plate

Answer 27

embryonic region that become the nervous sys; plate rolls up, forms neural tube; doral hollow nerve chord in chordates

Question 28

neural tube

Answer 28

develops into CNS; anterior portion is brain; remainder grow/dev into spinal chord

Question 29

neural crest formation

Answer 29

band of cells that dev along borders where NT pinched off ectoderm; cells migrate diffparts of embryo to form a variety of tissues (ex: nerves, teeth, skull bones)

Question 30

somites

Answer 30

block of cells in mesoderm lateral to notochord; organize body's structure; seg body of humans (vertebrae, ribs, muscles)

Question 31

1st trimester maternal changes

Answer 31

implated embryo in endometrium secretes hCG (human chorionic gonadotropin); first 2-4 wks embryo gets nutr from endometrium (thickened w gland for nutr fluid); trophoblast mingles/mixed w endometrium to form placenta; breasts enlarge; mucus plug forms; placental and uterine growht; ovulation/mentstural cycle cease; nausea

Question 32

hCG

Answer 32

minics LH; maintains corpus lutem, prevents distinegration; CL produces estradiol and progesterone

Question 33

placenta

Answer 33

organ of exchange btwn mother and embryo; nutr, O2, waste removed, embryo connected via umbilical cord

Question 34

1st tripmester embryonic changes

Answer 34

main period of organogenesis by 8 wks all major structures dev now called fetus; not all embryos successfuly complete dev: sponataneously stop dev due to chromosomal dev abnormalities;

Question 35

twins

Answer 35

inner cell mass (EP) may split during 1st moth into 2 groups of dev cells; 2 eggs released and fert

Question 36

ectopic preg

Answer 36

fert egg implants in oviduct

Question 37

monozygotic twins

Answer 37

genetically identical

Question 38

dizygotic twins

Answer 38

fraternal twins

Question 39

2nd trimester

Answer 39

lots of growth; active fetus; large uterus

Question 40

3rd trimester

Answer 40

even more grow + fetus fills up all space of mem; final tissue and organ differentiation; full term fetus after 37 wks (approx 6.6 lbs 20 inches); prematurity: born before 37 wks

Question 41

birth day

Answer 41

about 266 days; 38 wks; 9 months after fert

Question 42

3 stages of labor

Answer 42

dilation - cervix thins, opens up for fetus; delivery - expusion of baby; placental delivery - placenta exists body

Question 43

childbrith

Answer 43

begins w labor; rhythmic uterine contractions to push fetus and placenta out of body; hormones prosteglandins, estradiol, oxytocin guide this

Question 44

postnatal care

Answer 44

lactation