Brainstem Flashcards
Medial Lemniscus Arm vs Leg organization
Arms are at top, legs are at bottom
Pons Arms vs legs
Arms more medial, legs more lateral
Midbrain
Cant see 4th ventricle anymore, we see the cerebral aqueduct now
Cerebral Aqueduct
Tube connecting 4th ventricle and 3rd ventricle
Midbrain arms vs legs
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Cranial Nerves
Memorize all 12 cranial nerves
Olfactory nerve
- First cranial nerve
Sense of smell
Sensory
Optic nerve -
second cranial nerve
Eyes to brain
Sensory
Occulomotor nerve
Third Cranial Nerve
6 muscles that control your eyes
Controls 4 of the muscles - only motor neurons
Cranial nerves, motor or sensory?
Some are only motor
Some are only sensory
Some are mixed
Trochlear Nerve
Cranial Nerve 4
Controls a different muscle that controls movement of the eyes
Trigeminal Nerve
5
Sense of touch and pain in the face
E.g people studying headaches
Abducens nerve
6
Another eye muscle one
How many cranial nerves control eye muscles?
3
Vestibulocochlear nerve
8
Info about balance and hearing
Facial Nerve
7
Muscles in face
Bellspalsy - side of face is paralyzed
Glossopharyngeal Nerve
9
Sense of taste
Vagus Nerve ***Important
10
Main parasympathetic nerve controlling the internal organs(visceral organs)
Parasympathetic system
Slows heart down
Slows breathing
Constricts pupils
Increases intestinal motility
Hypoglossal nerve
13
muscles in your tongue
Spinal Accessory nerve
12
Muscles in back
Spinal cord - Dorsal Grey Matter
Sensory
Spinal Cord - Ventral Grey Matter
Motor
Spinal Cord - Middle grey Matter
Autonomic neurons
Info in and out
Visceral
Organization of cranial nerve nuclei and why is it different from spinal cord organization?
Different because of space created by 4th ventricle, all is spread.
Symmetrical on left and Right side
Top left and right: Somatic Sensory
Second: Visceral Sensory
Third: Visceral Motor
Bottom middle: Somatic Motor
In the brainstem where are the motor nuclei?
Medial
Where are the sensory nuclei in the brainstem?
Lateral
Where are the autonomic nuclei?
In between sensory and motor
Fiber tract - tract
Bundle of axons in CNS
Nerve
Bundle of axons in PNS
Projections
Extend from one region of NS to another
Which region of brainstem is most caudal?
Medulla
Cross-section of caudal medulla
Bundles of axons at top right and left
The more middle smaller are is the fasiculus gracilis
The area more at the side is the fasiculus cuneatus
Axons of dorsal columns
Fasiculus cuneatus
more lateral segregation of dorsal column
arms
Faciculus Gracilis
legs
more medial
Spinothalamic tract, other term?
Anteriolateral pathway
Correspondence of tract names
Where it starts and where it ends
e.g spinothalamic tract
Where is the second synapse of dorsal column axons
2nd order neurons in the dorsal column nuclei of the medulla
Nucleus gracilis
Input from legs and lower body
Nucleus Cuneatus
Input from arms and upper body
Nucleus
Collection of dendrites, cell bodies and synapses in the CNS
Ganglia
Collection of dendrites, cell bodies and synapses in the PNS
Rostral Medulla
What becomes visible?
Axons of dorsal column nuclei have crossed to the contralateral side of the brainstem to form a fiber tract called the medial lemniscus
4th ventricle becomes visible
Pons
Legs more lateral
Legs more medial
Midbrain
Cerebral aqueduct
How do sympathetic preganglionic neurons work?
Sympathetic preganglionic neurons release acetylcholine, which activates nicotinic
acetylcholine receptors on postganglionic neurons. Postganglionic neurons release
norepinephrine, which activates α and β adrenergic receptors on the target organs.
