Formation Of The Nervous System - 31

Question 1

What is Gastrulation?

Answer 1

The invagination to form the three germ layers

Question 2

What positions are determined during gastrulation?

Answer 2

Midline, anterior-posterior, dorsal-ventral

Question 3

What is the “animal hemisphere” in amphibians?

Answer 3

The part of the egg that is you’ll free

Question 4

What is the area called where the yolk is in amphibians?

Answer 4

The Vegetal Hemisphere

Question 5

Where does the invagination take place in amphibians? Humans?

Answer 5

Blastopore : Primitive Streak

Question 6

Why do humans not need an animal and vegetal hemisphere?

Answer 6

Our embryos get their nutrients from the placenta.

Question 7

What structure is formed during gastrulation? What germ layer forms it?

Answer 7

The Notocord : mesoderm

Question 8

What structure defines the midline of an embryo?

Answer 8

The Notochord

Question 9

What process occurs after gastrulation?

Answer 9

Neurulation

Question 10

What is neurulation?

Answer 10

The notochord sends inductive signals to the overlying ectoderm inducing neuroectoderm cells. Which will give rise to the entire nervous system.

Question 11

What is the neural plate?

Answer 11

A thickening of the midline ectoderm into columnar epithelium.

Question 12

What structures does the neural tube give rise to?

Answer 12

The brain and spinal cord

Question 13

Neural stem cells of the _________________ are called ____________________. The give rise to precursors that can make ________________, _________________, __________________.

Answer 13

Neural tube : Neural precursor cells : neurons, astrocytes, and oligodendrocytes.

Question 14

This precursor has stopped dividing and will differentiate into neurons

Answer 14

Neuroblasts

Question 15

This part of the neural tube is most differentiated.

Answer 15

The Floorplate

Question 16

What does the floorplate do?

Answer 16

Induces differentiation of the neural precursor cells. Also, gives the neural tube dorsovental polarity.

Question 17

What are somites and what will they become?

Answer 17

Thickening of the mesoderm adjacent to the neural tube. Will become axial musculature and skeleton.

Question 18

The brain arises from the _________________.

Answer 18

Anterior neural folds

Question 19

The peripheral nervous system is formed by the __________________.

Answer 19

Neural crest cells

Question 20

What are 3 basic principles of inductive cues?

Answer 20

They regulate gene expression (divide, differentiate, migrate); They can be graded (by molecule or receptor); they can be local (cell surface or not diffused)

Question 21

Where is Shh expressed during neurulation?

Answer 21

The notochord and floorplate

Question 22

Where is Noggin expressed during neurulation?

Answer 22

The notochord, floorplate, and roofplate (highest in roofplate)

Question 23

How do cels of the neural tube determine their differentiation?

Answer 23

Gradients of inductive factors (Shh and Noggin)

Question 24

What do cells of the ventral neural plate differentiate into?

Answer 24

These cells (floorplate) are exposed to more Shh and will become primary motor neurons

Question 25

What will the cells of the dorsal neural plate become?

Answer 25

These cells are exposed to a high amount of Noggin and will become sensory neurons

Question 26

Cells exposed to high amounts of Shh will become ___________________, whereas cells that are exposed to high amounts of noggin will become ___________________.

Answer 26

Motor neurons : sensory neurons

Question 27

What is the organization of the developing brain from Caudal to Rostral?

Answer 27

Cervical flexure : rhombencephalon : cephalic flexure : mesencephalon : Prosencephalon

Question 28

The prosencephalon will partition into the ________________ (rostral) and the _________________ (caudal)

Answer 28

Telencephalon : diencephalon

Question 29

The mesencephalon remains. The Rhombencephalon will partition into the _________________ (rostral) and the __________________ (caudal) separated by the _________________.

Answer 29

Metencephalon : myelencephalon : pontine flexure

Question 30

What are the optic cups?

Answer 30

Outcropping on the diencephelon

Question 31

The telencephalon gives rise to:

Answer 31

The cerebral cortex, hippocampus, basal ganglia, basal forbrain nuclei, and olfactory bulb

Question 32

The diencephalon will give rise to:

Answer 32

The thalamus and hypothalamus

Question 33

The optic vesicles give rise to the:

Answer 33

Retina

Question 34

The mesencephalon gives rise to:

Answer 34

The superior and inferior colliculi and the midbrain tegmentum

Question 35

How many days into development are all the brain structures partitioned?

Answer 35

100 days

Question 36

How much of the fetal development is devoted to cerebral cortex development?

Answer 36

6 months

Question 37

Neuromeres:

Answer 37

Repeating neural tube units. Cause segmentation of the developing nervous system.

Question 38

Homeotic genes

Answer 38

(Hox genes) TFs that bind to DNA region known as the homeobox.

Question 39

Hox genes are expressed in an _______________ to _______________ fashion.

Answer 39

Anterior to posterior

Question 40

How many times were the human Hox genes duplicated from the ancestral Hox cluster?

Answer 40

Twice

Question 41

How many neurons/min are generated at the peak of neuro genesis?

Answer 41

250,000

Question 42

What are the 2 zones of the neural tube from lumen to pial surface?

Answer 42

Close to the Lumen is the VENTRICULAR ZONE; close to the pial surface is the MARGINAL ZONE

Question 43

Where is the nuclei of neural precursor cells located during each part of its life cycle?

Answer 43

G1- ventricular zone : S- Marginal zone : G2- ventricular : M- detaches from pial surface and divides

Question 44

What two options does a newly decided cell have during proliferation in the neural tube?

Answer 44

After reconnecting to the pial surface, they can continue to proliferate, or they can stop differentiation and become a neuroblast that differentiates into a neuron