Early brain development

Question 1

Spina bifida

Answer 1

Part of the spinal chord protrudes through the back

Muscle weakness of the legs, paralysis, bowel and bladder problems
Can have deformed feet, uneven hips and curved spine

Question 2

Early development

Answer 2

Initial development starts at the 1st embryonic week with the process of gastrulation.
Ectoderm gives rise to the nervous system

Question 3

Gastrulation

Answer 3

Endoderm - urinary digestive and respiratory
Mesoderm - skeletal, muscular and cardiovascular
Ectoderm - skin and nervous system

Question 4

Neurulation

Answer 4

Formation of the neural tube
Neural plate in ectoderm - folding of the neural plate - neural tube

Question 5

Neural tube, notochord and neural crest

Answer 5

CNS
Inducer of neural tube formation
Peripheral nervous system

Question 6

Neural plate and neural tube

Answer 6

Thick layer of neuroectodermal precursor cells - stem cells that develop into neurons and glial cells or into skin cells

Question 7

Notochord

Answer 7

Temp structure - cylinder of cells in mesoderm that eventually becomes the vertebral column

Question 8

Neural crest cells

Answer 8

At the dorsal region where the neural tube closes, precursor cells differentiate into NCC
These cells migrate away from the neural tube and eventually develop into neurons of the PNS

Question 9

Inductive signals

Answer 9

Molecules produced and secreted by surrounding cells e.g notochord, primitive node

Question 10

Inductive signals and transcription

Answer 10

Inductive signals trigger the activation and expression of transcription factors. These are DNA-binding proteins, the functional end-product of genes. In turn, these transcription factor proteins regulate the expression of other genes by binding to the DNA. Similar to inductive signals, there are numerous examples of TFs involved in patterning of the CNS.

Question 10

Patterning

Answer 10

Fate of neural stem cells is defined = differentiation

Question 11

Transcriptional code

Answer 11

The combination of TFs determines the identity of specific neuron classes, by defining the fate of neural stem cells

Question 12

Sonic hedge hog - Dorsal ventral

Answer 12

Released by notochord

-Closes neural tube
-Defines ventral region: motor neurons in spinal cord and hind brain

Question 13

Nogging and Chordin -Dorsal ventral

Answer 13

Released by the notochord
-Define initial fate of neural stem cells - neurons instead of epidermal cells

Question 14

Anterior - posterior patterning

Answer 14

Based on development of a fruit fly
AP segmentation defines the body plan. Specific sets of genes are expressed in each segment of the drosophilia larvae. This gene expression program is determines by activation of transcription factors

Question 15

Hox genes

Answer 15

Family of genes that play a critical role in organizing the human body.
Each segment of the body expresses a specific combination of hox genes which determine structures (organs, limbs)
Humans have four sets compared to 1 in flies. Allows for more complex structures.

Question 16

Primitive node

Answer 16

Specialized cells that develop in ectoderm to induce formation of the neural plate and A-P patterning of neural tube.

Question 17

Retinoic acid

Answer 17

RA is a inductive signal produced by cells in Hensons node.
Expression of HOX genes is regulated by the gradient of RA

Question 18

Hensons node

Answer 18

Produces signalling molecules that induce pattern development of the neural tube. And supress certain signals.