Lecture 3: Development, Anatomy, And Function Of The Nervous System

Question 0

3 main processes involved in neurogenesis/gliogenesis

Answer 0

• proliferation: mitosis/cell division; takes place in the ventricular zone
• differentiation: cells specify via transcription factors that control gene expression
• migration: radial migration after formation; use radial glial cells as guidepost

Question 1

Neural stem cells

Answer 1

• produce all CNS neurons and glia
• proliferate via mitosis in the ventricular zone
• some exit the cell cycle and migrate from the ventricular zone to external layers of the nervous system

Question 2

What does it mean to say that the cerebral cortex forms in an “inside-out” manner?

Answer 2

Deeper cortical layers develop before more superficial layers

Question 3

Neural crest cells

Answer 3

• precursors of the majority of PNS neurons and glia
• multipotent and stem cell like
• give rise to PNS; facial bone, muscle, and nerves; thyroid, parathyroid, and thymus; heart tissue; and melanocytes

Question 4

Anencephaly

Answer 4

• neural tube defect in which the neurocore does not close properly
• no brain development
• fatal

Question 5

Spina bifida

Answer 5

• neural tube defect in which the neural cord does not close in the caudal region
• most survive with no cognitive impairments
• highly preventable by prenatal folate intake

Question 6

Gray matter

Answer 6

Predominately neuronal cell somas, dendrites, and astrocytes

Question 7

White matter

Answer 7

• predominately axons and their insulating glial sheets (oligodendrocytes) and astrocytes
• myelin gives white appearance

Question 8

How is gray and white matter organized in the brain?

Answer 8

Gray matter exterior and white matter interior

Question 9

How is gray and white matter organized in the spinal cord?

Answer 9

• white matter exterior and gray matter interior

- dorsal white matter consists of afferent neural axons, while ventral white matter consists of efferent neural axons

Question 10

Skull

Answer 10

• a bony structure in the head of vertebrates that protects the brain and supports the face
• composed of the cranium and mandible
• derived from mesoderm (and, less significantly, from neural crest)

Question 11

Vertebral column

Answer 11

• encloses the spinal cord
• also known as the backbone or the spine
• derived from mesoderm

Question 12

What are the 5 major regions along the length of the spine/spinal cord?

Answer 12

1) cervical
2) thoracic
3) lumbar
4) sacral
5) coccyx

Question 13

What are the 3 main subdivisions of the brain by developmental criteria?

Answer 13

• forebrain
• midbrain
• hindbrain

Question 14

What are the 3 main subdivisions of the brain by functional criteria?

Answer 14

• cerebrum (aka, forebrain or telencephalon +diencephalon)
• brain stem (midbrain + pons + medulla)
• cerebellum

Question 15

Cerebrum

Answer 15

• comprised of telencephalon + diencephalon

- also known as the forebrain

Question 16

Brain stem

Answer 16

• comprised of midbrain, pons, and medulla

- originates from the mesencephalon (midbrain), the metencephalon (pons), and the myelencephalon (medulla)

Question 17

Cortex

Answer 17

• laminated and is/was once on outside
• about 80% of human telencephalon
• 2 types: neocortex and allocortex

Question 18

Neocortex

Answer 18

• type of cortex with 6 horizontal layers of neurons
• “new” in mammals
• 90% of human cortex

Question 19

Allocortex

Answer 19

• archicortex
  
  • hippocampus and adjacent dentate gyrus
  • 3 layers
• paleocortex
  
  • pyriform or “olfactory” cortex
  • along bottom rostrally
  • “old” cortex of <6 layers

Question 20

What are the 2 “hidden” lobes of the cortex?

Answer 20

• insula (insular cortex)

- limbic “lobe”