Neurodevelopment

Question 1

What are the three layers of the gastrula and destiny? [6]

Answer 1

Endoderm- internal organs
Mesoderm- muscle, connective tissue, vascular system
Ectoderm - neural plate and skin

Question 2

Describe neural tube formation [6]

Answer 2

-Neuro plate folds in on itself
-Forms neural groove
-Eventually separates to form neural tube
-Caudal (spinal cord), Rostral (brain)
-Cells between neural tube and ectoderm form neural crest
-this will form much of the nervous system

Question 3

What is the role of BMPs [4]

Answer 3

-suppress potential for neural differentiation
-promote epidermal differentiation
-induce roof plate differentiation
-induce differentiation in neural crest cells

Question 4

Which cells synthesise BMPs? [2]

Answer 4

-Ectoderm (synthesise and secrete)
-Epidermal echoderm cells

Question 5

What is the role of organiser cells [2]

Answer 5

-produce BMP antagonists
-allow ectodermal cells to differentiate into neural tissue

Question 6

Identify the three neural flexures [6]

Answer 6

Cervical: between spinal cord and hindbrain
Cephalic: between midbrain and hindbrain
Pontine: straightens out cervical flexure

Question 7

Describe the rostrocaudal patterning on the neural tube [4]

Answer 7

-Wnt signalling is low at rostral end
-increases progressively towards the caudal end
-mesoderm caudal end produces Wnt
-Ectoderm at rostral produces Wnt inhibitors
-causes cell differentiation alongside FGFs and retinoic acid

Question 8

What is Shh? [4]

Answer 8

-Secreted by notochord
-morphogen, causes cell to differentiate into interneurones and motor neurones
-ventral patterning
-induces floor plate (specialised glial cells)
-Induces ventral neurones

Question 9

What are Hox genes? [5]

Answer 9

-encode for transcriptional factors that regulate development
-humans have 39 on 4 chromosomes
-genes at 3’ create more expression in rostral end
-genes at 5’ create more expression at caudal end
-control identity of neurones

Question 10

Progenitor cells can divide into: x3

Answer 10

-progenitor cells
-50:50 progenitor+ differentiated daughter cell
-2x differentiated daughter cells

Question 11

Describe radial cells [3]

Answer 11

-first to appear (cell bod and ventricular end, axon at pill surface)
-serve as progenitor cells
-role in neuronal migration

Question 12

Identify three ways neuronal cells migrate

Answer 12

Radial migration
Tangenital migration
Free migration

Question 13

Describe tangenital migration

Answer 13

-interneurones Preise from progenitor cells
-migrate to enter cortex
-switch to radial migration