Coding 15 Flashcards
What makes the neural plate?
Ectoderm
What induces the presumptive neural tissue induction?
Prechordal plate and notochord
What will the ectoderm also make?
Epidermis
Where are the presumptive neural crest cells situated?
Between the epidermis and the CNS
What do the NSC make?
Melanocytes and PNS
What forms with high BMP?
Epidermis
What forms with low BMP?
Neural plate
What forms with intermediate BMP?
NSC formation
What is primary neurulation?
Cells surround the neural plate and proliferate to separate from the ectoderm and make a hollow tube
What does sox1 induce?
Activates genes for the neural plate
What does sox2 induce?
Inhibits the formation of epidermis and NSC
What is secondary neurulation?
Neural tube forms from the mesenchyme cells
What is the transition zone?
Where the anterior and posterior parts of the neural tube join together
How does the neural tube detatch from the surface ectoderm?
By the loss of E-cadherin expression and the transition to the expression of N-cadherin
When does the neural tube fuse?
Day 27
Which ectoderm cells express the sox2 gene?
The ectoderm cells that will form the posterior neural tube
What are the 3 vesicles that the anterior neural tube will make?
- Forebrain
- Midbrain
- Hindbrain
What are rhombomeres?
The hindbrain develop swelling segment patterns that divide into many components
What do the rhombomeres make?
Neurons with different cell fate the neural crest cells form ganglia which can then form different types of nerves
Which neurons are sensory?
The neurons of the dorsal region
Which neurons are motor?
The neurons of the ventral region
What does SHH make?
SHH makes the floor plate of the neural tube
What secretes SHH?
Floor plate cells to make the ventral neural tube
What does high SHH lead to?
The production of motor neurons
What determines dorsal fate?
BMP4
What happens if a notochord fragment is removed from an embryo?
The adjacent neural tube will NOT have a floor plate
What happens if notochord fragments are replaced with SHH secreting cells OR from one embryo to the host is inserted?
A second floorplate and second set of motor neurons will form
What level of BMP does the neural plate have?
Low
What level of BMP does the neural crest cell have?
Intermediate
What level of BMP does the ectoderm/epidermis have?
High
How does the BMP level end up high above the neural tube?
Due to the lateral-medial movement
What is a neural crest cell?
These are cells that form along the entire neural tube (so it is ectoderm) and it starts in the dorsal region
How do the neural crest cells migrate?
Repulsion from Eph (receptor) on the posterior scleretome and the neural crest cell surface has the ephrin ligand
What do Foxd3/slug/snail do for neural crest cells?
They repress E-cadherin and lead to EMT
What is chemotaxis?
When the neural crest cells migrate by attraction
What is a placode?
A thick surface of ectoderm
What does high BMP make?
Epidermis
What does intermediate BMP make?
Neural crest cells
What does low BMP make?
Neural plate
What does sox2 inhibit?
Epidermis
What does the primary neurulation make?
Anterior neural tube
What does secondary neurulation make?
Posterior neural tube
What is the transition zone?
Where the anteiror and posterior join
When does the anterior neuropore close?
Day 24
What does the posterior neuropore close?
Day 27
What are rhombomeres?
These are segments that are made from the rhombencephalon that encode for neurons
Where is BMP the highest?
Surface ectoderm
Where is SHH the highest?
Floor plate
What does the high BMP form?
Dorsal structures
What does the high SHH form?
Ventral structure
What forms at the sweet spot between SHH and BMP?
Motor neurons
