Flashcards in Unit 6 Deck (38):
Areas of the midbrain
- Cerebral aqaeduct (of sylvius)
- Cerebral peduncles
"Roof" of the midbrain; in this case a posterior roof
The tectum is ____ to the cerebral aqueduct
What is the Tectum composed of?
- Quadrigeminal plate made up of 4 collicular bodies (2 superior and 2 inferior
Channel for CSF exchange between the 3rd and 4th ventricles
- Cerebral Aqueduct
Surrounds the cerebral aqueduct
- Periaqueductal gray substance
What is present in the preiaqueductal gray?
- Nuclei from CNs 3 and 4
What is ventral to the cerebral aqueduct?
- Cerebral peduncles
What do the cerebral peduncles include?
- Tegmentum (ventral to the aqueduct)
- Substantia Nigra (toward the middle)
- Crus Cerebri (ventral and lateral aspect)
Smallest of the CNs
- CN IV
What does CN IV innervate?
- Superior Oblique
Apparent origin of CN IV
- Out of the mid-dorsal aspect just inferior to the inferior colliculus
Apparent origin of CN III
- Ventral from the interpeduncular fossa
- The 6 nuclei of origin are located in the pariaqueductal gray substace area
Fibers from which nucleus contribute preganglionic parasymapthetic fibers to CN III?
- Edinger-Westphals' nucleus (of the midbrain)
4 bumps exist in the mamalian tectum called what?
- Superior and inferior colliculi
The superior colliculi deals with what reflexes?
- Some visual
The inferior colliculi deals with what reflexes?
- Some auditory
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?
The tectospinal tract influences the neurons in the upper cervical through CN __, which contracts what muscles to prevent head injury?
- SCM, and trapezius
Lesions in the tectum don't impair voluntary eye movemtns, but the do impair what?
- Perception of motion of objects in the field of vision
Area just ventral to the cerebral aqueduct
What is located in the tegementum?
- Nuclei of origin for CNs III and IV
- Reticular formation of the midbrain
- Nucleus Ruber (Red nucleus)
Although the nucleus ruber is primarily in the midbrain, the superior part extends where?
- Diencephalon's subthalamic region
What is the red nucleus divided into?
- Magnocellular area (Inferior large cell area)
- Parvocellular (Highly vascular superior area)
What tract fibers originate in the megnocellular area of the midbrain?
Input fibers that go into the red nucleus
- The central cerebellar nuclei (except the fastigial)
- Cerebral cortex
Functions of the nucleus ruber
- Contralateral motor responses necessary for postural control and muscle tone control primarily in flexor musculature
Where is the substantia nigra located?
- Between the tegmentum and the crus
Where does the substantia nigra extend into?
- Subthalamus of the diencephalon
What gives substantia nigra its black appearance?
What are afferent and efferent fibers of the substantia nigra exchanged between?
- The telecephalon's caudate and putamen nuclei
What does the caudate and putamen nuclei make up most of?
- Basal ganglia (corpus striatum) of the Cerebellum
What was Parkinson's DIsease first called?
- Paralysis agitans
Symptoms of Parkinson's Disease
- Shaking of digits, hands, and tongue at rest
- Odd postures (flexing forward)
- Shuffling gates
- Loss of speech in later stages
Parkinson's Disease is associated with what?
- A drop in dopamine in the Substantia Nigra
Ventrolateral aspect of the cerebral peduncle
- Crus Cerebri
The Crus Cerebri is composed of descending tracts of fibers from the Cerebral Cortex. Some examples are:
- Corticospinal fibers (to the cord)
- Corticopontine fibers (to the pons)
- Corticobulbar fibers (to the M.O.)