W20-L2: An Overview of the Brainstem Flashcards
What is wrong with Anencephalic babies?
Born without a forebrain
Role of the brainstem
- Reflexive and unconscious behaviour.
- Modulation of various arousal and conscious states
- Provides survival centres
What are important structures of the brainstem?
- Cranial nerve nuclei and related structures
- Reticular formation and related structures.
- Long fibre tracts
- Cerebellar circuitry
What is the tegmentum?
Structure in the brainstem which is continuous with the spinal cord
What makes up the tectum?
Superior and Inferior Colliculi (only at level of midbrain)
What is the rule of 4?
4 cranial nerves exit at the medulla IX-XII, 4 exit the pons, V, VI, VII, VIII and 4 above the pons I-IV
From which plate is sensory and motor nuclei developed?
Sensory nuclei develop from the Alar plate
Motor nuclei develop from the basal plate.
Where are motor and sensory nuclei positioned?
Motor nuclei are closer to midline.
Sensory nuclei positioned laterally.
How are nuclei within the brainstem located?
Medial 3 columns are motor, lateral 3 are sensory columns
Where is the reticular formation found?
Found at every level and is continuous both rostrally and caudally
What is the caudal reticular formation refexes?
Reflexes with crucial functions in motor reflex and autonomic functions like spinal cord eg Ventrolateral medullary reticular formation which regulates GI via vagus
What are the three major pathways that pass through the brainstem?
Dorsal column-medial lemniscus system, anterolateral system and corticospinal tract
Where does the corticospinal tract occupy in the brainstem?
The ventral aspect top to bottom
What does the dorsal aspect of the brainstem have?
Cranial nerve nuclei Reticular formation
Ventral aspect of the midbrain is made up of what?
cerebral peduncles, substantia nigra, red nuclei (along with corticospinal tract)
