Lecture 2

Question 1

which germ layer is rolled upwards to create the neural tube (and neural plate) during neurulation?

Answer 1

ectoderm

Question 2

what germ layer is rolled down to create the gut tube?

Answer 2

endoderm

Question 3

what two structures are important for instructing neurulation?

Answer 3

notochord

prechordal mesoderm

Question 4

the ectoderm forms that neural plate, which is induced by the up regulations of ______ while the node (organizer), notochord, and prechordal mesoderm will block _____ activity.

Answer 4

up regulation of FGFs

block BMP-4 activity

Question 5

up-regulation of FGFs and blocked BMP-4 activity during neurulation activates neural pathway in what 2 regions of the brain?

Answer 5

fore and midbrain only

Question 6

hind brain and spinal chord induction are dependent upon increased _____ and ____ as well as increased BMPs, which are only secreted at the midline

Answer 6

increased FGF and WNT

Question 7

the neural plate will form neural folds that will elevate and fuse in the midline to form the neural tube, a primitive form of the ____

Answer 7

central nervous system

Question 8

cells of the neuroepithelium that form at the tips of the neural folds and then migrate to other regions to form many structures, including: spinal ganglia, bones and connective tissue of the face, septa for the outflow tract of the heart, some cranial nerve ganglia, ganglia for the guy tube (enteric ganglia), melanocytes, etc.
vulnerable to teratogenic insult and provide a rationale for why many children with facial clefts also have cardiac defects
like a “fourth germ layer”

Answer 8

neural crest cells

Question 9

layer of the ectoderm where neural crest cells form

located at top of neural tube where the crests of the tubes come together

Answer 9

neuroectoderm layer

Question 10

neural crest cells will migrate out of the spinal cord when the cord is _____

Answer 10

closed

Question 11

neural crest cells will migrate out of the head region while the neural tube is still open and forms _____-

Answer 11

the bones of the face

Question 12

rolling of the middle portion of the ectoderm to form the neural tube starts _____ and moves ____

Answer 12

cranially (head) and moves caudally (toward body)

Question 13

formed from the mesoderm
eventually form vertebrae
head forms first then rest forms

Answer 13

somites

Question 14

what happens if the primitive streak goes too far caudally?

Answer 14

sacrococcygeal teratoma

Question 15

what happens if the primitive streak stops short?

Answer 15

caudal dysgenesis (mermaid syndrome)

Question 16

closing of the neural tube begins in the ____ then zippers up and down
occurs around 22 days

Answer 16

neck region

Question 17

derived from the medodermal germ layer

Answer 17

mesoderm

Question 18

any loose connective tissue

may be derived from mesoderm, neural crest, etc.

Answer 18

mesenchyme

Question 19

defect due to lack of closure at different regions of the neural tube
Ex: Anencephaly, Spina Bifida, Spina Bifida Occulta

Answer 19

neural tube defects

Question 20

NTD
failure of cranial neural folds to close causing brain tissue to generate
fatal
folic acid is a preventative measure

Answer 20

anencephaly

Question 21

NTD
open neural tube anyhwere from cervical to lumbosacral area (most common)
70% prevents by taking folic acid for 3 months prior to conception and throughout pregnancy

Answer 21

spina bifida

Question 22

NTD
tube closes but vertebra does not
covered by skin (and often, patch of hair)
very common
increased risk of having a child w/ NTD if you already have a child or family history with NTD

Answer 22

spina bifida occulta

Question 23

during formation of the lateral plate mesoderm, the ______ grows downward and around the yolk sac, pinching off what will become the gut tube
leads to creation of intra-embryonic cavity

Answer 23

amnion

Question 24

double mesoderm layer formed during formation of lateral plate meoderm
similar to connecting stalk
suspends the guy and allows a pathway for blood vessels, nerves, and lymphatics

Answer 24

mesentery

Question 25

mesoderm derived from somites | leads to creation of vertebral column, muscles, and dermis

Answer 25

paraxial (dorsal) mesoderm

Question 26

form in the head region and contribute ot the skull and muscles of the face not quite somites

Answer 26

somitomeres

Question 27

mesoderm that leads to urogenital structures

Answer 27

intermediate ventral mesoderm

Question 28

mesoderm that splits into splanchnic (visceral-organs) and somatic (parietal-lines body cavity)

Answer 28

lateral plate (ventral) mesoderm

Question 29

duct that keeps the gut connected w/ the yolk sac

Answer 29

vitelline duct

Question 30

will become the umbilical cord

Answer 30

allantois

Question 31

mesoderm tissue originally lying cranial to the heart but repositioned b/w the heart and connecting stalk by cranial folding of the embryo gives rise to the central tendon of the diaphragm, connective tissue for the liver, and ventral mesentery as the embryo grows and curves in fetal position, the heart gets tucked into thoracic cavity some mesoderm around the heart proliferates and creates the _____

Answer 31

septum transversum

Question 32

programmed cell death is necessary to cause the ____ to fall away so folding can finish

Answer 32

yolk sac

Question 33

defect due to abnormal closure of one or more of the body folds

Answer 33

ventral body wall defects

Question 34

``` ventral body wall defect usually located on right side more common defect in infants from young mothers intestines outside of body abnormal closure of abdomen ```

Answer 34

gastroschisis

Question 35

ventral body wall defect not due to abnormal closure | caused by faulure of bowel loops to return to abdominal cavity following umbilical hernation

Answer 35

omphalocele

Question 36

created by proliferation of tissue around the heart fills up a lot of space from sternum to the back separates thoracic cavity and peritoneal cavity due to cranial folding that curved the heart into the thoracic region contributes to central tendon of the diaphragm

Answer 36

septum transversum

Question 37

what part of the spine innervates the diaphragm?

Answer 37

C3, 4, 5 | C 3, 4, 5 keeps the diaphragm alive!

Question 38

what fold grows out toward the septum transversum to make the pericardio-peritoneal canals?

Answer 38

pleuroperitoneal fold

Question 39

most common type is a hole on the left side (probably bc liver is on the right) can push on developing heart and lungs and cause spontaneous abortion fetal surgery can patch hole and save baby

Answer 39

diaphragmatic hernia

Question 40

mesoderm that grows around lungs to cover them

Answer 40

visceral mesoderm

Question 41

membrane that eventually covers the heart

Answer 41

pleuropericardial membrane

Question 42

what nerve is located in the pleuropericardial membrane and runs down both sides of pericardial sac?

Answer 42

phrenic nerve

Question 43

the visceral mesoderm creates the ______ pericardium during formation of the pleural and pericardial cavities

Answer 43

fibrous pericardium

Question 44

what are the four body folds?

Answer 44

``` cephalocaudal (Head and tail folds) lateral folding (2 lateral folds close the gut tube around umbilcal region) vitelline duct (connects yolk sac to gut) ```

Question 45

what are the 2 ways in which blood vessels are formed?

Answer 45

vasculogenesis | angiogenesis

Question 46

blood vessels formed in situ form blood islands then these cells coalesce into endothelial tubes and establish major vessels (aorta, cardinal veins) regulated by vascular endothelial growth factor and its receptors

Answer 46

vasculogensis

Question 47

blood vessels formed from sprouting from existing vessels | regulated by vascular endothelial growth factor and its receptors

Answer 47

angiogenesis

Question 48

for divisions of the gut

Answer 48

pharyngeal, fore, mid, and hind gut

Question 49

two closures of the gut

Answer 49

cranial (buccopharyngeal) | caudal (cloacal membrane)

Question 50

expanded portion of the hind gut | later forms the urogenital sinus and part of anal canal

Answer 50

cloaca

Question 51

three cavities derived from the space between the two layers of the lateral plate mesoderm

Answer 51

cardiac pleural peritoneal

Question 52

layer of mesoderm that surrounds the gut tube, heart, and lungs

Answer 52

splanchnic (visceral) layer of lateral plate mesoderm

Question 53

layer of mesoderm that lines the body wall

Answer 53

somatic (parietal) layer

Question 54

2 layers of lateral plate mesoderm form ______ that secrete fluid for lubrication 2 layers are continuous at the root of each system

Answer 54

serous membranes

Question 55

suspends the gut double layer of peritoneum 2 layers are continuous

Answer 55

mesentery

Question 56

genes that contain conserved DNA binding motifs from the homeotic gene complex of Drosphilia grouped into 4 clusters and regulate anterior-posterior (craniocaudal) patterning of the embryo

Answer 56

Homeobox genes (HOX genes)

Question 57

period of organogenesis most sensitive to teratogenic insults b/c organ primordia are forming

Answer 57

3-8th week

Question 58

posterior to septum transversum | connect primitive pleuropericardial and peritoneal cavities

Answer 58

pericardioperitoneal canals

Question 59

membranes that close pericardiperitoneal canals

Answer 59

pleuroperitoneal membranes

Question 60

membranes that grow around hte heart and separate the pleural and pericardial cavities form fibrous pericardium

Answer 60

pleuropericardial folds

Question 61

what forms the diaphragm?

Answer 61

pleuroperitoneal membranes septum transversum (central tendon) muscular components from cervical myotomes (C 3,4,5) carrying phrenic nerve mesentery of the esophagus (crura)

Question 62

dorsal portion of each somite that forms the dermis of the skin of the back segmented and supplied by spinal nerves from the segments at which they originated segmental pattern maintained as they migrate over the body--each region that they occupy on the skin is also called a ____ and is innervated by the same spinal nerve that originally supplied the __ region of the somite (each blank is the same word)

Answer 62

dermatome

Question 63

???

Answer 63

epimere

Question 64

branch of a spinal nerve that innervates intrinsic back muscles derived from primaxial muscle cells skin over the back

Answer 64

dorsal primary ramus

Question 65

ventral branch of a spinal nerve that innervates limb and trunk muscles except the intrinsic ("true") back muscles

Answer 65

ventral primary ramus

Question 66

an extended column of midline cells lying immediately ventral to the floor plate of the central nervous system extends from the hypophysis to the end of the spinal cord important for inducing the neural plate and the sclerotome portion of the somites to form vertebrae major signal molecule is sonic hedgehog (SHH)

Answer 66

notochord

Question 67

the ventral (motor) region of the brain and spinal cord

Answer 67

neural plate

Question 68

cranial and caudal openings in the neural tube that exist from the time that closure of the neural folds is initiated until it is complete, i.e. unclosed portions of the closing neural tube

Answer 68

neuropores

Question 69

mesoderm-derived tissue along the axis of the embryo | responsible for forming somites and somitomers

Answer 69

paraxial mesoderm

Question 70

a thickened region of ectoderm that forms sensory organs and ganglia Ex: nasal, otic, lens, epibranchial

Answer 70

placodes

Question 71

mesoderm-derived layer lying between the paraxial and lateral plate layers responsible for forming much of the urogenital system

Answer 71

intermediate mesoderm

Question 72

mesoderm-derived tissue that splits into visceral and parietal layers surrounding the organs and body cavity

Answer 72

lateral plate mesoderm

Question 73

epithelia balls of cells formed in segmental pairs along the neural tube from paraxial mesoderm differentiate into vertebrae, muscles of the back and body wall, and dermis of the skin

Answer 73

somites

Question 74

ventromedial part of each somite that forms the vertebrae

Answer 74

sclerotome

Question 75

formation of blood vessels from blood islands in situ (i.e. in its original place)

Answer 75

vasculogenesis

Question 76

formation of blood vessels by sprouting from existing vessels

Answer 76

angiogenesis

Question 77

common chamber for the hindgut and urinary systems anterior portion forms the urogenital sinus posterior portion forms the anus

Answer 77

cloaca

Question 78

connection b/w the yolk sac and the primary intestinal loop of the midgut through the connecting stalk failure of this duct to degenerate results in fistulas and diverticula (Meckel's diverticulum) from the small intestine to the umbilicus

Answer 78

Vitelline duct

Question 79

layer of lateral plate mesoderm associated with ectoderm | forms parietal pleura, parietal peritoneum, etc.

Answer 79

somatic (parietal) mesoderm

Question 80

transcription factors that contain a a specific DNA-binding motif (sequence) within a region called the homeodomain important for patterning the embryonic axis, establishing different regions of the brain, determining the origin and type of guy derivatives, patterning the limbs, etc.

Answer 80

Homeobox genes