Flashcards in Mesoderm and Endoderm/ Neural Crest - Final Deck (23):
4 Mesodermal Tissues and what they form:
1) Chordamesoderm- notochord
2) Paraxial mesoderm - head and somites of three types
3) Lateral Plate mesoderm: splanchnic, somatic, and extra embryonic tissue
4) Intermediate Mesoderm: Creates kidney's and gonads
What are the three types of somite tissue, and what do they form?
Sclerotome - vertebrae
Dermatome - Skin
Myotome - muscle ( dorsal axial)
Ret receptors stimulated by GNDF.
What receptor is sometimes not working that results in growth complications?
Places where human head ossification is incomplete in infants.
Difference between cranial and trunk neural crest:
trunk neural crest fate is determined by localized environment.
Two migratory routes of neural crest
Through the anterior sclerotome, or dorsally over the mesoderm and under the dermis.
C kit and steel factor.
C kit is a receptor for steel factor. Both are required for the survival of neural crest cells. An example of a mutation, is lack of c-kit for neural crest melanocytes. The animal will then have a white spot on their forehead and stomach.
Cleft lip and cleft palate
failure of external prominences lead to cleft lip. Failure of internal palatal shelves lead to cleft palate.
Contain filopodia with actin that crawls and senses the direction axons need to travel.
Chemo and Contact Attraction/Repulsion
Attraction: netrins and cadherins. Repulsion: semaphorin and ephrins.
Different sensory neurons respond differently to different attractants and repellants T/F
What direction to neurons travel in the spinal cord?
Nerves travel to the ventral part where Netrin 1 is being expressed. Commissional neurons cross over the midline.
Which types of neurons have greater or less affinity for the tectum?
More Eph receptors on temporal neurons than nasal neurons. Nasal neurons make it farther on the tectum.
What type of tissue starts limb formation?
limb bud mesenchyme, low hox, high FGF
How to grow another limb
FGF soaking beads
Tbx 4 and Tbx 5
4 - hind, 5 - fore
Apical Ectoderm Ridge - non specific growth factor for limb formation. Requires FGF though.
Proximal/Distal Limb establishment
Hox genes and FGF/ RA
Anterior/Posterior Limb establishment
Zone of polarizing activity (ZPA) exists at the posterior of the limb and will decide fate based on proximity to ZPA
mimics the effects of the anterior/posterior limb axis ZPA. Also plays a role in digit expression due to binding to enhancer elements.
Lack of Shh, no great anterior / posterior patterning, leads to cyclops.