Brainstem Flashcards
This deck tests your knowledge of the brainstem's anatomy and physiology.
What are the main parts of the brainstem?
- Diencephalon
- Midbrain
- Pons
- Medulla Oblongata
Draw out all the cranial nerve exits in the brainstem. Hint: CN 1 not included, CN II forms optic tract out of diencephalon.
Refer to Notion.
What are the main parts of the diencephalon?
- Thalamus
- Hypothalamus
- Epithalamus
- Subthalamus
What does the thalamus do?
- “Sensory relay station”
- Grey matter mass, contains many nuclei
- Processes almost all senses (except olfactory) before their signals reach cortex
What does the hypothalamus do?
- Autonomic control (homeostasis; SNS/PNS regulation; works with limbic system to influence emotions/drives)
- Endocrine control (pituitary gland)
What does the epithalamus do?
- Pineal gland (melatonin)
What does the subthalamus do?
- Works with cerebellum and basal ganglia to integrate and modulate motor signals
What is the reticular formation, and where is it found?
- Network of nuclei
- Found throughout the brainstem
What does the reticular formation do?
- Maintains consciousness
- Maintains autonomic vital functions (breathing)
What are the main parts of the midbrain?
- Tectum
- Tegmentum
- Cerebral peduncles
- Midbrain (part of the) reticular formation
What does the tectum consist of, and what does it do?
- Superior colliculus (visual reflex centers, for tracking visual stimuli)
- Inferior colliculus (auditory reflex centers, for reacting to sound)
What does the tegmentum consist of, and what does it do?
- Periaqueductal gray (modulates descending pain pathway signals, in response to pain/fear)
- Red nuclei (relays info about fine motor control from cerebellum > spinal cord)
- Substantia nigra (produces dopamine; lesion = Parkinson’s)
What do the cerebral peduncles do?
- Nerve fiber bundles for motor signal conduction from cortex > brainstem > SC)
What does the midbrain (part of the) reticular formation do?
- Contains vertical gaze center (RiMLF)
- Lesion leads to vertical eye movement paralysis + diplopia
What cranial nerves exit the midbrain?
CN III and IV
What does the pons do?
- Sensory and motor relay station (ascending / descending tracts; cerebellum / cortex)
- Horizontal gaze center (PPRF; lesion leads to horizontal eye movement paralysis + diplopia)
- Regulates REM sleep (by paralysing muscles)
- Respiratory centers
- Maintains consciousness
What cranial nerves exit the pons?
CN V to VIII
What does the medulla oblongata do?
- Sensory and motor relay station (ascending / descending tracts)
- Reflex centers (gag, cough, sneeze, swallow, vomit)
- Maintains autonomic functions (cardiac centers - inotropic and chronotropic control; vasomotor centers - vasodilation and vasoconstriction; respiratory centers - depth and rate of breathing)
What cranial nerves exit the medulla oblongata?
CN IX - XII
Why do CN I and II not exit from the brainstem?
They exit from above the brainstem level, via the olfactory bulb and optic tract respectively
