Exam 1 (Lecture 1) - Cerebrum

Question 1

Discuss the BASIC embryological origin of cerebral structures discussed in class.

Answer 1

1) Neural tube forms from neural ectoderm

2) Anterior (cranial) portion of the tube grows more than posterior (caudal) portion

3) Anterior portion constrained by the skull & becomes the brain

4) Posterior portion becomes the spinal cord

**most rostral region of neural tube = telencephalon

Question 2

Telencephalon

Answer 2

Gives rise to:

1) Cerebrum
2) Rhinencephalon

Question 3

Describe the topographical relationships between structures derived from the telencephalon.

Answer 3

1) Depressions = sulci (sulcus)
2) Elevations = gyri (gyrus)

• Fissures/sulci to know:
  1) pseudosylvian fissure
  2) cruciate sulcus
  3) longitudinal fissure
• Gyri to know:
  1) sylvian gyrus
  2) ectosylvian gyrus
  3) suprasylvian gyrus
  4) precruciate gyrus
  5) postcruciate gyrus
  6) occipital gyrus

Question 4

Gray Matter
vs.
White Matter

Answer 4

Describes the appearance of the fresh-cut tissue.

1) Gray matter:
a) cell bodies (of neurons)
b) dendrites
c) axons (axon hillock)
d) glial cells
e) capillaries

2) White matter:
a) axons (bundled together; no neuronal cell bodies).
b) glial cells
c) capillaries

Question 5

Gray Matter of the Cerebrum

Answer 5

1) Cerebral cortex

2) Basal nuclei (motor system)
- caudate (one on each side) “the eyes of the nice lady”

Question 6

White Matter of the Cerebrum

Answer 6

1) Corpus callosum:
- axons
- connect functional areas of R & L hemispheres

2) Internal capsule:
- cerebral afferents & efferents
- carry info to and from cerebrum (efferent & afferent on both R & L sides)

Question 7

Direction of Information Flow in Nervous System

Answer 7

1) Within neuron:
- info into dendrites
- info out at axon terminal

2) Neuron to neuron:
- presynaptic = sending info; “talking”
- postsynaptic = getting info; “listening”

3) Brain structure to brain structure:
- afferent fibers (bringing into; sensory) = arrives
- efferent fibers (sending info; motor) = exits

Question 8

Neuronal Classification

Answer 8

1) Unipolar = one connection to cell body

2) Bipolar = one input and one output

3) multipolar = lots of inputs at cell body