Nervous system development

Question 1

What is the name of the embryonic tissue that forms the nervous system?

Answer 1

Ectoderms

Question 2

At what day does the first sign of nervous system developing occur? What is the structure?

Answer 2

Day 16 - neural plate

Question 3

Describe the formation of a neural tube. By what day is this formed?

Answer 3

Neural plate cells develop neural crest cells. These curve round to form a neural hollow. The neural crest cells then join each other forming a neural tube. This occurs by day 21. The neural tube is lined with nor-epithelium.

Question 4

What is the role of the notochord?

Answer 4

To act as a trigger for a sequence of events to occur e.g. formation of the neural tube.

Question 5

Incomplete closure of the neural tube can cause abnormalities. What are the effects of an anterior and posterior neuropore?

Answer 5

Incomplete closure of the anterior part of the neural tube causes encephally = brain doesnt form, resulting in a miscarriage.
Incomplete closure of the posterior part of the neural tube causes spina-bifida (lower limb paralysis)

Question 6

What does the rostral part of the brain form? What are the 3 main divisions?

Answer 6

This forms the brain. The 3 main divisions are the prosencephalon (the forebrain), the mesencephalon (the midbrain) and the rhombencephalon (the rear/hindbrain.

Question 7

What does the prosencephalon divide into?

Answer 7

The telencephalon (cerebral hemispheres and basal ganglia) and diencephalon (thalamus and hypothalamus)

Question 8

What does the lumen of the neural tube become?

Answer 8

The spinal canal and ventricles

Question 9

This structure forms the dorsal root ganglion, PNS neuroglial cells e.g. schwann cells and non-neural tissue such as muscle. What is it?

Answer 9

Neural crest cells.

Question 10

What does the outer aspect of the neural tube become and what is the name of its lining?

Answer 10

This becomes the PNS.

Nor-epithelium. It produces 50,000 neurones a second

Question 11

Define apoptosis

Answer 11

Programmed cell death - occurs when the number of neurones surpasses that of the mature brain

Question 12

Define migration

Answer 12

The movement of young neurones from their origin to their target cells/allocated structures in the nervous system.

Question 13

What is the role of radial glial cells?

Answer 13

To aid the migration of young neurones.

Question 14

Define differentiation.

Answer 14

The formation of specialised cells.

Question 15

What are some effects of the environment on a developing child?

Answer 15

Foetal alcohol syndrome - disrupts the migration of young neurones.
Drugs/lack of exercise/diet.

Question 16

Why is there rapid growth of the brain in the 1st 4 years of life?

Answer 16

Myelination - formation of the corpus collosum and white matter in the CNS and PNS- speeds up the rate of impulse conduction by allowing salutatory conduction.
Synaptogenesis - formation of many new synapses and dendrites
Proliferation of neuroglial cells.