Unit 6

Question 1

Areas of the midbrain

Answer 1

• Tectum
• Cerebral aqaeduct (of sylvius)
• Cerebral peduncles

Question 2

“Roof” of the midbrain; in this case a posterior roof

Answer 2

• Tectum

Question 3

The tectum is ____ to the cerebral aqueduct

Answer 3

• Posterior

Question 4

What is the Tectum composed of?

Answer 4

• Quadrigeminal plate made up of 4 collicular bodies (2 superior and 2 inferior

Question 5

Channel for CSF exchange between the 3rd and 4th ventricles

Answer 5

• Cerebral Aqueduct

Question 6

Surrounds the cerebral aqueduct

Answer 6

• Periaqueductal gray substance

Question 7

What is present in the preiaqueductal gray?

Answer 7

• Nuclei from CNs 3 and 4
• Endorphins
• Enkephalins

Question 8

What is ventral to the cerebral aqueduct?

Answer 8

• Cerebral peduncles

Question 9

What do the cerebral peduncles include?

Answer 9

• Tegmentum (ventral to the aqueduct)
• Substantia Nigra (toward the middle)
• Crus Cerebri (ventral and lateral aspect)

Question 10

Smallest of the CNs

Answer 10

• CN IV

Question 11

What does CN IV innervate?

Answer 11

• Superior Oblique

Question 12

Apparent origin of CN IV

Answer 12

• Out of the mid-dorsal aspect just inferior to the inferior colliculus

Question 13

Apparent origin of CN III

Answer 13

• Ventral from the interpeduncular fossa

- The 6 nuclei of origin are located in the pariaqueductal gray substace area

Question 14

Fibers from which nucleus contribute preganglionic parasymapthetic fibers to CN III?

Answer 14

• Edinger-Westphals’ nucleus (of the midbrain)

Question 15

4 bumps exist in the mamalian tectum called what?

Answer 15

• Superior and inferior colliculi

Question 16

The superior colliculi deals with what reflexes?

Answer 16

• Some visual

Question 17

The inferior colliculi deals with what reflexes?

Answer 17

• Some auditory

Question 18

Both sets of colliculi utilize which tract for proprioceptive reflexes which allows us to move our head away from loud sounds and also objects moving rapidly in our field of vision?

Answer 18

• Tectospinal

Question 19

The tectospinal tract influences the neurons in the upper cervical through CN __, which contracts what muscles to prevent head injury?

Answer 19

• XI

- SCM, and trapezius

Question 20

Lesions in the tectum don’t impair voluntary eye movemtns, but the do impair what?

Answer 20

• Perception of motion of objects in the field of vision

Question 21

Area just ventral to the cerebral aqueduct

Answer 21

• Tegmentum

Question 22

What is located in the tegementum?

Answer 22

• Nuclei of origin for CNs III and IV
• Reticular formation of the midbrain
• Nucleus Ruber (Red nucleus)

Question 23

Although the nucleus ruber is primarily in the midbrain, the superior part extends where?

Answer 23

• Diencephalon’s subthalamic region

Question 24

What is the red nucleus divided into?

Answer 24

• Magnocellular area (Inferior large cell area)

- Parvocellular (Highly vascular superior area)

Question 25

What tract fibers originate in the megnocellular area of the midbrain?

Answer 25

- Rubrospinal

Question 26

Input fibers that go into the red nucleus

Answer 26

- The central cerebellar nuclei (except the fastigial) | - Cerebral cortex

Question 27

Functions of the nucleus ruber

Answer 27

- Contralateral motor responses necessary for postural control and muscle tone control primarily in flexor musculature

Question 28

Where is the substantia nigra located?

Answer 28

- Between the tegmentum and the crus

Question 29

Where does the substantia nigra extend into?

Answer 29

- Subthalamus of the diencephalon

Question 30

What gives substantia nigra its black appearance?

Answer 30

- Melanin

Question 31

What are afferent and efferent fibers of the substantia nigra exchanged between?

Answer 31

- The telecephalon's caudate and putamen nuclei

Question 32

What does the caudate and putamen nuclei make up most of?

Answer 32

- Basal ganglia (corpus striatum) of the Cerebellum

Question 33

What was Parkinson's DIsease first called?

Answer 33

- Paralysis agitans

Question 34

Symptoms of Parkinson's Disease

Answer 34

- Shaking of digits, hands, and tongue at rest - Odd postures (flexing forward) - Pain - Shuffling gates - Loss of speech in later stages

Question 35

Parkinson's Disease is associated with what?

Answer 35

- A drop in dopamine in the Substantia Nigra

Question 36

Ventrolateral aspect of the cerebral peduncle

Answer 36

- Crus Cerebri

Question 37

The Crus Cerebri is composed of descending tracts of fibers from the Cerebral Cortex. Some examples are:

Answer 37

- Corticospinal fibers (to the cord) - Corticopontine fibers (to the pons) - Corticobulbar fibers (to the M.O.)

Question 38

These axons terminate on CN nuclei 3 and 4 to initiate voluntary motor movements of the eyes

Answer 38

- Corticomesencephalic fibers