Exam III

Question 1

Riddle found that treating the anterior part of a chick wing with RA caused cells in that region to behave like cells in the posterior organizing region. These cells began to express the RNA produce of what gene?

Answer 1

Shh

So RA is not the morphogen, but Shh is

Question 2

The region of a limb expressing Shh is also known as the what?

Answer 2

ZPA

Question 3

What are the 3 axes defining the vertebrate limb?

Answer 3

Dorsoventral
Anterior-posterior
Proximodistal

Question 4

Transplantation experiments have allowed researchers to reverse one or more of the limb axes. What was the result of transplanting the limb disc to the opposite side in terms of axis and limb formation?

Answer 4

AP axis is reverse but not the DV axis

A normal limb forms but AP axis is reversed

Question 5

Transplantation experiments have allowed researchers to reverse one or more of the limb axes. What was the result of rotating a limb disc 180 degrees in terms of axis and limb formation?

Answer 5

Both the AP axis and DV axis will be reversed

A normal limb will form but only its AP axis is reversed (suggests that AP is established earlier than DV)

Question 6

Paraxial mesoderm signals via retinoic acid based on a _________ code

Answer 6

Hox

Question 7

Expression of _______ initiates the future forelimb

Answer 7

Tbx5

Question 8

Expression of _____ and _______ initiate future hindlimb

Answer 8

Tbx4 and Pitx-1

Question 9

What are the initial initiators of limb development?

Answer 9

Tbx5 and Tbx4

Question 10

What is the effect of Gli-3 and Hand-2 in terms of limb axes?

Answer 10

Expression of Gli-3 anterior and Hand-2 posterior fix the AP axis

Question 11

What component of the limb interacts with the underlying limb bud mesoderm and promotes continued outgrowth of the limb bud?

Answer 11

Apical ectodermal ridge

Question 12

Cells in the posterior part of the limb bud are under the influence of ______________ and differentiate into proximal limb components

Answer 12

RA

Question 13

What germ layer of the limb bud is involved in dermination of actual limb morphology?

Answer 13

Limb bud mesoderm (it is limb-specific)

Question 14

What happens to the limb when AER is removed?

Answer 14

There is no further outgrowth of the limb bud

Question 15

What gene is involved in pattern formation of the proximodistal limb axis in chick limb buds?

Answer 15

Hoxd

Question 16

What cellular process is responsible for “carving” the shape of the limb?

Answer 16

Apoptosis

Question 17

If the cells from the potential necrotic (apoptotic) region of a developing limb are removed and cultured in vitro, what happens to the cells?

Answer 17

They die on cue

Question 18

Apoptosis is a mechanism for ____________

Answer 18

Morphogenesis

Question 19

What are 2 specific zones of the limbs that are found to be shaped by apoptosis?

Answer 19

Posterior necrotic zone becomes axilla

Areas between future digits (so humans do not have webbed fingers/toes)

Question 20

In motor axon guidance studies, an eye was transplanted to the side of an embryo after forelimb rudiment was removed. What happened to the brachial nerves in this area?

Answer 20

The nerves deflected from their normal path and grew towards transplanted eye, but failed to penetrate into it and establish a connection

Outgrowing nerves are non-specific, so any tissue will attract nerves, but connections are only made between corresponding tissues!

Question 21

What happened in the motor axon guidance study where a forelimb rudiment of a salamander embryo was removed so that the limb failed to develop? (In terms of brachial plexus nerves)

Answer 21

Brachial plexus nerves remain smaller than they would if limb were still there.

Spinal ganglia 3, 4, and 5 (associated with brachial plexus in salamander) are also smaller

Question 22

What happened in the motor axon guidance study where an additional limb rudiment was transplanted to the flank of a salamander embryo (in terms of local spinal nerves)

Answer 22

Local spinal nerves supply the innervation to the transplanted limb and these local nerves increase in thickness

Ganglia associated with these nerves increase in size; the increase in number of cells may be as much as 40%

Question 23

Proximal cells of limb bud produce _________ _________

Answer 23

Scatter factor

Question 24

Premuscle cells in the somite express _______ which is the receptor for scatter factor

Answer 24

C-met

Question 25

Migrating pre-muscle cells express _______ and ________

Answer 25

Pax-3 and N-cadherin

Question 26

Differentiation of premuscle cells into muscle within the limb bud depend on ______ expressed by limb bud ectoderm

Answer 26

Wnt-6

Question 27

After skeletal element condensations form, myogenic cells condense into 2 muscle masses:

Answer 27

Flexors and extensors

Question 28

What inhibits BMP in the region of the future joint cavity?

Answer 28

Noggin

Question 29

What malformation is characterized by reduced number of digits and wide separation between anterior and posterior digits and is often due to disruption ot middle portion of AER in late limb formation?

Answer 29

Split hand-foot malformation

Question 30

what condition is associated with persistent mechanical pressures of the uterine wall of the fetus, particularly in cases of oligohydramnios?

Answer 30

Talipes equinovarus = club foot

Question 31

The notochord induces formation of the floor plate of the neural tube via __________

Answer 31

Shh - when produced by the floor plate this induces formation of motor neurons

Question 32

Note that the ectoderm flanking the nerual plate uses _____ to induce Snail-2 in the future neural crest and later to maintain ______ and ______ to create a dorsalizing effect

Answer 32

BMPs | Pax-3 and Pax-7

Question 33

What suppresses Pax-3 and Pax-7 from the floor plate to suppress the dorsalizing effect from occuring in the basal plate?

Answer 33

Shh

Question 34

Motor axons grow out of motor neuroblasts located in what location of the spinal cord?

Answer 34

Basal plate (Shh)

Question 35

Cell bodies of sensory neurons are derived from what type of cells?

Answer 35

Neural crest

Question 36

Cell bodies of sensory neurons form _________ _________ ________

Answer 36

Sensory spinal ganglia

Question 37

Axons grow from sensory neuron cell bodies in how many directions?

Answer 37

2 - toward spinal cord and periphery. So it is harder for sensory neurons than motor

Question 38

Growth cones adhere strongly to a substrate containing _______

Answer 38

Laminin

Question 39

Attractant or repulsive? Netrins vs. semaphorins

Answer 39

``` Netrins = attractant Semaphorins = repulsive ```

Question 40

What determines whether migrating neural crest cells differentiate into autonomic neurons or other neural crest derivatives?

Answer 40

BMPs

Question 41

Postganglionic sympathetic cells are typically __________

Answer 41

Adrenergic

Question 42

How are adrenergic postganglionic sympathetic nerves converted to cholinergic neurons when they innervate sweat glands?

Answer 42

Via cholinergic differentiation factor

Question 43

Are postganglionic parasympathetic cells typically cholinergic or adrenergic?

Answer 43

Cholinergic

Question 44

Primary neural inductors (2)

Answer 44

Primitive node | Notochordal process

Question 45

Cranial end of neural tube divides into _________ brain. caudal part of early brain becomes subdivided into neuromeres, of which _________ are most prominent

Answer 45

Tripartite | Rhombomeres

Question 46

What type of genes are expressed in regular order in the rhombomeres?

Answer 46

Homeobox genes

Question 47

The isthmic organizer is located at the junction between midbrain and hindbrain and acts by production of ______ anteriorly and ______ posteriorly

Answer 47

Wnt-1 | FGF-8

Question 48

CN V = arch 1 = rhombomere _____ CNVII = arch 2 = rhombomere ______ CN IX = arch 3 = rhombomere ______

Answer 48

2 4 6

Question 49

Midbrain dorsoventral patterning is due to ______ located ventrally

Answer 49

Shh

Question 50

Shh restricts expression of _____and similar molecules in the midbrain

Answer 50

Pax-7

Question 51

Pax-7 is related to formation of the alar plate | ______ is expressed in alar plate of diencephalon and is "master gene" of eye formation

Answer 51

Pax-6

Question 52

During midbrain DV formation, Pax-6 inhibits _____ and vice versa. This reciprocal inhibition results in the formation of the diencephalic mesencephalic border

Answer 52

En-1

Question 53

What are the 3 patterning centers of the forebrain?

Answer 53

Rostral (FGF-8) Dorsal (BMPs and Wnts) Ventral (Shh)

Question 54

_______ genes seem responsible for the differentiation of specific nuclei in the myelencephalon

Answer 54

Hox

Question 55

What is the major topographical change from the myelencephalon to the spinal cord?

Answer 55

Expansion of the roof plate to form thin roof over 4th ventricle

Question 56

What cells are primarily responsible for building up the gray cortical areas?

Answer 56

Radial glial cells

Question 57

Mutations in weaver and reeler result in what regarding cortical development?

Answer 57

You don't get a cortex - not a viable embryo

Question 58

Where do neural crest cells originate?

Answer 58

Lateral margins of neural plate

Question 59

Induction of neural crest tissue comes from non-neural ectoderm using ______ and ______

Answer 59

BMPs and Wnts

Question 60

Inductions from mesoderm on neural crest tussue comes from ______

Answer 60

FGF-8

Question 61

Robo/Slit Neurophilin/semaphorin ephrin/eph Are used as ligand/receptor pair guidance molecules for what/

Answer 61

Neural crest cells

Question 62

Describe early, later, and late migratory neural crest cells in terms of their potential for differentiation

Answer 62

``` Early = most potential Later = can only be cels of dorsal locations (spinal ganglia) Late = can only form melanoblasts ```

Question 63

While in neural tube, neural crest cells are epithelial. CAMs are lost, and Snail-1, Snail-2, and Foxd3 are important for the cells to break free. What factor maintains the competence of neural crest cells to differentiate into autonomic neurons?

Answer 63

Mash-1

Question 64

What are the 3 major lineages of trunk neural crest?

Answer 64

``` Sympathoadrenal lineage Sensory lineage (VL path) Melanocyte lineage (DL path) ```

Question 65

Sensory lineage of trunk neural crest gives rise to what to cell types?

Answer 65

Dorsal root ganglia | Schwann cells

Question 66

What trunk neural crest lineage do adrenal chromaffin cells, adrenergic sympathetic neurons, and cholinergic sympathetic neurons come from?

Answer 66

Sympathoadrenal

Question 67

________ is expressed in the mesentery near the gut and prevents neurons from crossing the midline of the CNS

Answer 67

Slit-2

Question 68

Trunk neural crest cells express ________, the Slit receptor and avoid cels that express Slit-2. Vagal crest cells do not express this receptor and are able to cross to the gut wall

Answer 68

Robo

Question 69

The ________ is a lateral evagination of the diencephalon which enlarges distally to form the optic vesicle

Answer 69

Optic stalk

Question 70

The groove in the asymmetrical invagination of the optic vesicle is called the ______ ________

Answer 70

Choroid fissure

Question 71

Failure of the choroid fissure to close leads to ________

Answer 71

Colobomo

Question 72

What artery uses the choroid fissue and optic stalk to pass into the posterior chamber of the eye?

Answer 72

Hyaloid artery - this artery degenerates in adult

Question 73

High concentrations of Shh inhibit Pax-6. Low concentrations of Shh in distal optic stalk permit expression of Pax 6 so that the ______ can form

Answer 73

Retina

Question 74

High concentrations of Shh in the proximal stalk decrease expression of Pax6 and induce expression of _______ to provide guidance of axons of ganglion cells from retina

Answer 74

Pax2

Question 75

Where is the cornea derived from?

Answer 75

Neural crest

Question 76

What factor is necessary for corneal induction?

Answer 76

Pax6

Question 77

Absence of pax 6 acting on the optic vesicle would lead to formation of what?

Answer 77

Lens placode

Question 78

What factor is responsible for establishing the nasotemporal axis of the eye?

Answer 78

Ephrins

Question 79

How does ventropin influence the DV axis of the eye?

Answer 79

Inhibits BMP-4

Question 80

What separates the stomodeum from the cranial end of the gut tube?

Answer 80

Oropharyngeal membrane

Question 81

What is the earliest representation of the facial region is the stomodeum and what is this derived from?

Answer 81

Stomodeum - derived from ectoderm

Question 82

What genes influence DV patterning in craniofacial development?

Answer 82

Dlx genes

Question 83

Arch 1 ectoderm uses _____ to signal migrating neural crest cells and heavily influences development of arch 1

Answer 83

Edn-1

Question 84

Signaling from what center is necessary for development of neural crest derivatives involved in lower facial morphogenesis?

Answer 84

Cranial ectoderm

Question 85

Cranial ectoderm is prepatterned by ______ signals from pharyngeal endoderm

Answer 85

FGF-8

Question 86

The frontonasal ectodermal zone is an ectodermal signaling center involving establishment of FGF-8 dorsally and Shh ventrally, resulting in shaping of the ____

Answer 86

Tip of the snout

Question 87

Segmentation of the cranial neural tube during facial development occurs as a result of what genes?

Answer 87

Hox

Question 88

True or false: pharyngeal arch patterning is dependent on neural crest

Answer 88

False

Question 89

What stage of tooth development is the first time enamel organ and dental papilla come together?

Answer 89

Bell stage

Question 90

What tooth component is a condensation of mesenchymal cells around the developing tooth which will form the cementum and periodontal ligament?

Answer 90

Dental sac

Question 91

What factor is necessary for tooth formation to continue past bud stage?

Answer 91

Pax-9

Question 92

Cleft lip results from lack of fusion of _______ and _______ processes

Answer 92

Nasomedial | Maxillary

Question 93

Meckel's cartilage is derived from pharyngeal arch 1 and is the main component of what embryonic structure?

Answer 93

The lower jaw

Question 94

Differentiation of pharyngeal arch 1 is associated with what factor

Answer 94

Otx-2

Question 95

Reichert's cartilage is associated with what pharyngeal arch?

Answer 95

Second

Question 96

Development of the second pharyngeal arch is dependent on what factor (this is necessary to prevent arch 2 from differentiating into arch 1)

Answer 96

Hoxa2

Question 97

What process is a ventral downgrowth from the floor of the diencephalon and forms the neurohypophysis?

Answer 97

Infundibular process

Question 98

What is a midline upgrowth from the roof of the stomodeum and is stimulated by BMP-4 followed by FGF-8 from the floor of diencephalon?

Answer 98

rathke's pouch

Question 99

What part of rathkes pouch forms the pars intermedia?

Answer 99

Inner layer of cup

Question 100

What layer of rathke's pouch forms the anterior pituitary?

Answer 100

Outer layer of cup

Question 101

Derivatives of pouch 1

Answer 101

Tympanic cavity | Auditory tube

Question 102

Derivatives of pouch 2

Answer 102

Fossa for palatine tonsils

Question 103

Derivatives of pouch 3

Answer 103

``` Inferior parathyroids (Shh) Thymus (BMP-4) ```

Question 104

Derivatives of pouch 4

Answer 104

``` Superior parathyroids Postbranchial body (becomes associated with cells that secrete calcitonin) ```

Question 105

What begins as node between pharyngeal arches 1 and 2 and expresses TFs Hhex, Nkx-21, Pax8, and Foxe1?

Answer 105

Thyroid

Question 106

The opening of the thyroid diverticulumd of thyroid anlage persists as a small pit at the base of the tongue called the :

Answer 106

Foramen cecum

Question 107

What kidney structure gives rise to adult ureter, renal pelvis, and collecting tubules?

Answer 107

Metanephric diverticulum

Question 108

Each mesonephric duct forms an evagination called

Answer 108

The ureteric bud or metanephric diverticulum

Question 109

Metanephrogenic blastemata form the ____ of the adult kidney

Answer 109

Renal tubules

Question 110

Ureteric diverticula forms what type of structures?

Answer 110

Hollow

Question 111

What represses GDNF in anterior regions of metanephros?

Answer 111

Slit-2/Robo2

Question 112

What reduces sensitivity to GDNF in anterior mesonephric duct?

Answer 112

Sprouty

Question 113

What makes the ureter epithelium impermeable to water?

Answer 113

Uroplakins

Question 114

What inhibits BMP in the region of the metanephrogenic blastema?

Answer 114

Gremlin

Question 115

What forms epididymis, seminal vesicle, and vas deferens in male?

Answer 115

Mesonephric ducts

Question 116

What forms efferent ductules in male?

Answer 116

Mesonephric tubules

Question 117

Rete cords form what?

Answer 117

Rete testis

Question 118

What forms seminiferous tubules with sertoli and interstitial cells?

Answer 118

Sex cords

Question 119

What forms glans penis or clitoris?

Answer 119

Genital tubercle

Question 120

What forms shaft of penis or labia minora?

Answer 120

Genital folds

Question 121

What forms scrotum or labia majora?

Answer 121

Genital swellings

Question 122

What factor is necessary to make primordial germ cells meiosis competent cells?

Answer 122

Dazl

Question 123

Aortic arches 1 and 2

Answer 123

Degenerate

Question 124

What aortic arch forms internal carotid?

Answer 124

3rd pair

Question 125

Common carotids are derived from

Answer 125

Ventral aorta between 3rd and 4rth aa's

Question 126

What forms right subclavian a.?

Answer 126

Right 4th arch

Question 127

What forms the aortic arch?

Answer 127

Left 4th aortic arch

Question 128

What aortic arches become associated with pulmonary system?

Answer 128

Sixth pair

Question 129

the dorsal part of left 6th aortic arch remains connected to dorsal aorta as a fetal shunt; it closes but remains as what structure in adults?

Answer 129

Ligamentum arteriosus

Question 130

Initial formation of cardiac tube is guided by

Answer 130

Tbx2

Question 131

Chamber myocardium formation is guided by

Answer 131

Tbx5

Question 132

Does chamber myocardium have strong or slow contraction?

Answer 132

Strong

Question 133

Does primary myocardium have strong or slow contraction?

Answer 133

Slow

Question 134

Absence of hand 1

Answer 134

Defective L ventricle

Question 135

Absence of Hand 2

Answer 135

Absence of right ventricle

Question 136

What forms outflow tract of heart?

Answer 136

Secondary heart field, endothelial components of cephalic paraxial, and lateral mesoderm near otic placode, neural crest

Question 137

What gives rise to coronary vasculature and vasculature of smooth muscle?

Answer 137

Proepicardium

Question 138

What space is formed within the septum secundum?

Answer 138

Foramen ovale