• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

Card Range To Study



Play button


Play button




Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

37 Cards in this Set

  • Front
  • Back

Neural crest cell formation

Neural crest cells pinch off from the dorsal neural tube and migrate in a pre set pattern. Grouped based on pinching area and what they form

Cranial Neural Crest

Cartilage, bone, cranial neurons, glia, connective tissues of the face

Pharyngial arches --> thymic cells, odontoblasts, bones of the middle ear, jaws

Trunk Neural crest

sensory neurons or melanocytes

Vagal and caral neural crest

parasympathetic ganglia of the gut

Cardiac neural crest

contribute to face structures as well as connective tissue of arteries

CNC - intramembranous ossification


Neural crest derived mesenchymal cells condense into nodules where then differentiate to become osteoblasts - bone precursor cells which secrete osteoid matrix that binds Ca

Depends on CBFA1 transcription factor (runx2 marker)

CBFA1 mutant - cartilage no bone

Origin of frontal and parietal bones - mammal

Neural crest (ectodermal) and mesodermal

Trunk neural crest cell migration in chick

Two pathways

1. Early: Ventral pathway through anterior, ROSTRAL sclerotome (mesoderm that becomes vertebral cartilage origionate from somites). Become sensory and sympathetic neurons, adrenomedullary cells and schwann cells

2. Late: dorsolateral pathway. Become melanocytes

Ventral pathway migration is dependent on components of ECM and chemotactic factors

ECM modecules in anterior sclerotome permit migration: fibronectin, laminin, collagen, proteoglycan

ECM obstructions: ephrins and semaphorin

Dorsal pathway occurs after maturation of dermatomes - mesoderm originating from somites, becoming back dermis

*timing of somite differentiation regulates spatial and temporal migration of the neural crest cells*

Travel through dermis and epidermis to developing hair follicles

Cardiac neural crest

Heart forms in neck region under pharyngeal arch acquiring cells from neural crest

Cardiac NCC migrate - bellow otic vesicle, through arches, along aoritc arch arteries, into outflow tract of heart

Generate endothelium of aortic arches and septum between aorta and pulmonary artery

Pax3 transcription factor

Neural plate border:

Cranial placodes

Wnts, BMPs, FGFs and RA induce neural plate border specifier transcription factors (prevent region from becoming neural plate or epidermis)

These regulate NCC specifiers (induce neural crest fate) and pre-placodal specifiers



Neural crest

Neural groove


Ventral pathway

Dorsal pathway


Neural tube




Sensory placodes

Local transient thickening of the ectoderm in the head and neck

Give rise to sensory neurons that form distal portions of ganglia

Vision, hearing, balance, taste, smell

Proximal portions of ganglia formed from Cranial NCC

Lens placodes - reciprocal induction

Optic vesicle envaginates from diencephalon, contacts ectoderm, induces thickening, forms lens placode, and eventually lens pit

Lens pit then induces

optic vesicle to become optic cup which forms retina

optic cup stays connected with diencephalon through optic stalk

pit fills in optic cup and closes, detaches from ectoderm and forms lens vesicle

Lens vesicle

Composed of proliferating progenitor lens cells

- posterior lens vesicle cells exit mitosis, differentiate

-anterior lens vesicle cells remain as monolayer and form anterior lens epithelium

Gastrulation and neurulation of the chick embryo

Notochord extends beneath the neural tube

Paraxial mesodem on either side of the neural tube is presomitic mesodem (PSM) somites form from rostral end

Somites differentiate into




Lateral plate mesoderm splits into




Anterior to the trunk mesoderm is

Prechordal plate mesoderm

Trunk Mesoderm

1. Chordamesoderm - notochord

2. Paraxial mesoderm - somites form and produce connective tissues of back

3. Intermediate mesoderm - urogenital system, cortical portion of adrenal gland

4. Lateral plate mesoderm - circulatory system, body cavity lining, limbs except for muscle

Divisions due to increasing amounts of BMP

BMP gradient and mesoderm formation

High - ventral and lateral - lateral plate mesoderm

Lower - intermediate mesoderm

Absence - paraxial mesoderm, BMP antagonists such as chordin and nogin

intermediate mesoderm


paraxial mesoderm

lateral plate mesoderm

Paraxial mesoderm becomes the head and somites

Sommites become

Sclerotome - vertebrae, ribs, rib cartilage

Myotome - musculature of the back, ribs, limbs

Dermatome - dermis of the back

Minor components:

Syndetome - tendons

Endothelial cells - generate vascular cells in dorsal aorta

Paraxial mesoderm

Initially unsegmented, then forms somites for a short time before they develop further

# of somites is species specific

Somites determine migration path of NCC, spinal nerve axons and form vertebrae, ribs, dorsal dermis, skeletal muscle of back, body and limbs

Noggin is responsible for

Somite formation

When inserted into lateral plate mesoderm, somite forming paraxial mesoderm is formed

Somitogenesis issues

1. periodicity

2. fissure formation

3. epithelialization

4. specification

5. differentiation

Somite boundries

quail presumptive boundry cells cause a boundry when transplanted in a chick

quail non boundry cells do not

*notch signalling pathway helps with boundry formation*

quail non boundry cells transplanted but local ectopic expression of notch induced, somite boundry is induced

Notch signalling pathway

Juxtacrine signaling

Notch is a receptor on cell membrane, interacts with ligand on adjacent cell, intracellular portion of notch is cleaved and it goes to nucleus, influences gene expression

Delta like 3

The ligand for notch

If mutated it disrupts somite formation

Results in rib malformation and aberrant ossigication

Hairy 1

transcription factor, wave gradient moving caudal to rostral through unsegemented paraxial mesoderm

eventually just a thin band at anterior point is left, defines the posterior of the next

Clock and wave mechanism form somites

RA expression follows hensens node regression from A to P, in balance with FGF the trigger

Notch the clock stimulates Hairy1 an effector

and inhibitor, its own inhibitor

Creates wave of gene expression to form anouther somite

Simple negative feedback loop

Somite separation

EphrinB2 ligand at the posterior of the anterior somite interacts with EphA4 receptor, tirosine kinase in the unsegmented mesoderm

Gap forms in the presomitic mesoderm

Anterior cells to the gap ungergo epithelialization first become posterior somite

Posterior cells of the gap undergo epithelialization later

MET - mesenchymal to epithelial transition create mesodermal somites surrounded in epithelium

MET in peripheral somatic cells

Caused by ectodermal signals

Cells polarize - sub apical surface inward, basal membrane outside

Cells synthesize ECM fibronectin protein and Ncadherin