Exam 2 - Development of the nervous system

Question 1

The first major phase of neurodevelopment is formation of the​

A) neural tube.​

B) neural grove.​

C) growth cones.​

D) neural plate.

Answer 1

D

Question 2

The neural plate develops directly into the​

A) neural embryo.​

B) neural groove.​

C) brain.​

D) CNS.

Answer 2

B

Question 3

In addition to radial migration of developing neurons, there is considerable __________​

migration.​

A) rapid​

B) tangential​

C) intermediate​

D) circuitous

Answer 3

B

Question 4

Cell adhesion molecules are thought to play a major role in​

A) differentiation.​

B) aggregation.​

C) proliferation.​

D) sprouting

Answer 4

B

Question 5

In a classic study, Sperry cut the optic nerves of frogs, rotated their eyes 180e, and waited for​

regeneration. Once the frogs regained their vision, there was evidence that​

A) sprouts had grown out from undamaged nerves into available retinal target sites.​

B) axons had grown back into the retinas from the optic tectums.​

C) axonal connections had been reestablished in such a way that vision was perfectly normal,​

despite the rotation of the eyes.​

D) despite the eye rotation, each axon grew out from the retina to the same area of the optic​

tectum to which it had originally been connected.

Answer 5

D

Question 6

What are the phases of development of the nervous system?

Answer 6

1. induction of neural plate
2. neural proliferation
3. migration and aggregation
4. axon growth and synapse formation
5. neuron death and synapse rearrangement

Question 7

Ecoderm

Answer 7

outermost layer of embryonic cell, becomes skin

Question 8

Mesoderm

Answer 8

middle layer of embryonic cell, becomes connective tissue

Question 9

Endoderm

Answer 9

innermost layer of embryonic cell, becomes lining of organs

Question 10

Totipotent

Answer 10

earliest cells have the ability to become any type of body cell

Question 11

Stem cells

Answer 11

• unlimited capacity for self-renewal
• can develop into different mature cell types (multipotent)

Question 12

Radial migration

Answer 12

towards the outer wall of the tube

Question 13

Tangential migration

Answer 13

at a right angle to radial migration, parallel to the tube walls

Question 14

What are the two methods of migration? Explain.

Answer 14

1. somal - an extension develops that leads migration, cell body follows
2. glial-mediated migration - cell moves along a radial glial network

Question 15

Cell-adhesion molecules (CAMs), where are they found?

Answer 15

aid both migration and aggregation
- found on cell surfaces

Question 16

What is the importance of the growth cone? What is the growth cone?

Answer 16

• at the growing tip of each extension, extends and retracts filopodia as if finding its way
• important for accurate axon growth

Question 17

What are the filopodia that are retracted and extended by the growth cone guided by? What hypothesis explains this?

Answer 17

chemoaffinity hypothesis - postsynaptic targets release a chemical that guides axonal growth

Question 18

Guidance molecules (chemoattractants and chemorepellants), what are they released by?

Answer 18

-released by glia
- chemoattractants attract growing axons
- chemorepellants repel them

Question 19

Fasciculation

Answer 19

the tendency of developing axons to grow along the paths established by the pioneer growth cone’s path

Question 20

Synaptogenesis, what type of cell is this dependent on, and high levels of what are needed for this?

Answer 20

• formation of new synapses
• glial cells - astrocytes
• cholesterol

Question 21

Neutrophins

Answer 21

promote growth and survival, guide axons, stimulate synaptogenesis

Question 22

Necrosis

Answer 22

• passive cell death
• cell death associated with injury

Question 23

Apoptosis

Answer 23

• active cell death
• programmed cell death
• cleaner than necrosis

Question 24

Prefrontal cortex

Answer 24

• working memory, planning and carrying out sequences of actions, inhibiting inappropriate responses

Question 25

Neurons and synapses that are not activated by experience usually do, or do not survive?

Answer 25

do not survive

Question 26

What does an enriched environment result in?

Answer 26

- thicker cortices - greater dendritic development - more synapses per neuron

Question 27

What does early visual deprivation result in?

Answer 27

- underdeveloped visual cortex - fewer synapses and dendritic spines in primary visual cortex - deficits in depth and pattern vision

Question 28

Tinnitus, what does this cause?

Answer 28

ringing in the ears - major reorganization of primary auditory cortex

Question 29

Savants

Answer 29

intellectually handicapped individuals who display specific cognitive or artistic abilities

Question 30

Where is brain damage most commonly seen in autism?

Answer 30

cerebellum

Question 31

__________ - if given early in pregnancy, increases chance of autism.

Answer 31

thalidomide

Question 32

Evidence for a role in autism of a gene on which chromosome has been found?

Answer 32

chromosome 7

Question 33

What are the 3 core symptoms of autism?

Answer 33

1. reduced ability to interpret emotions and intentions 2. reduced capacity for social interaction 3. preoccupation with a single subject or activity - also have trouble interacting

Question 34

What are some characteristics of people with William's syndrome?

Answer 34

- sociable, empathetic, and talkative - exhibit language and music skills - enhanced ability to recognize faces

Question 35

What is severely impaired in people with William's Syndrome?

Answer 35

spatial cognition (telling time)

Question 36

A gene on which chromosome is associated with William's Syndrome?

Answer 36

chromosome 7

Question 37

People with William's Syndrome will often have underdeveloped ________ and ________ cortex, and normal _____ and ______.

Answer 37

- occipital and parietal - frontal and temporal