7. Cranial Nerves and Limbic System Flashcards
(19 cards)
Which cranial nerves emerge from the brainstem?
Cranial nerves 3-12
These include those from the midbrain, pons, and medulla.
Do cranial nerves have dorsal and ventral roots?
No
Unlike spinal nerves, cranial nerves do not have these roots.
What are the classifications of cranial nerves?
- Special sensory nerves
- Pure motor nerves
- Mixed nerves
These classifications indicate the function of the nerves.
Which cranial nerves are classified as special sensory nerves?
- I (olfactory - smell)
- II (optic - vision)
- VIII (vestibulocochlear - hearing/balance)
These nerves are purely sensory.
Identify the pure motor cranial nerves.
- III
- IV
- VI
- XI
- XII
These nerves are responsible for motor functions.
Name the mixed cranial nerves.
- V (trigeminal)
- VII (facial)
- IX (glossopharyngeal)
- X (vagus)
Mixed nerves have both sensory and motor functions.
Which cranial nerves carry parasympathetic fibers?
- III
- VII
- IX
- X
These nerves have parasympathetic functions.
What is the function of the trigeminal nerve (V)?
General sensory for face/head; motor for chewing muscles
It has both sensory and motor functions.
What functions does the facial nerve (VII) serve?
Special sensory for taste; motor for facial expression
It provides taste sensation and controls facial muscles.
Describe the role of the glossopharyngeal nerve (IX).
Special sensory for taste; general sensory for pharynx/tongue; motor for swallowing muscles
It has both sensory and motor functions.
What functions are associated with the vagus nerve (X)?
Some taste function; motor for pharynx/larynx; parasympathetic control of thoracic/abdominal organs
This nerve plays a critical role in autonomic functions.
What is the limbic system often referred to as?
The ‘emotional/feeling brain’
It sits between the ‘thinking brain’ (neocortex) and ‘instinctual brain’ (brainstem).
What are the key structures of the limbic system?
- Hypothalamus
- Amygdala
- Hippocampus
Each structure has distinct functions related to emotion and memory.
What is the main function of the hypothalamus?
Regulates homeostasis, autonomic control, hormones
It controls hunger, thirst, body temperature, and emotions.
What role does the amygdala play in the brain?
Processes fear, aggression, excitement, anxiety
It is known as the ‘fear center’ of the brain.
What is the function of the hippocampus?
Critical for memory processing, storage, retrieval
It is affected early in Alzheimer’s disease.
What is the trisynaptic circuit in the hippocampus?
- Perforant pathway: Entorhinal cortex → Dentate gyrus
- Mossy fibers: Dentate gyrus → CA3 region
- Schaffer collaterals: CA3 → CA1 region
This circuit is essential for memory function.
Information enters the hippocampus via _______.
entorhinal cortex
This is the pathway for incoming information.
Information exits the hippocampus via _______.
subiculum
This structure is involved in the output of processed information.
