Brainstem Flashcards
(32 cards)
FEATURES OF THE ANTERIOR MEDULLA
- PYRAMID: also called corticospinal tracts. Ventrally located. Provide efferent information for voluntary movement.
- OLIVE: or inferior olivary eminence.
FEATURES OF THE POSTERIOR MEDULLA
- GRACILE AND CUNEATE TUBERCLES: two nuclei. Sensory information from the limbs (not pain and temperature) first synapse here.
- GRACILE AND CUNEATE FASCICULI
CRANIAL NERVES OF THE MEDULLA
from CN 8 to 12.
- XII Hypoglossal (hyppo-under).
- XI, accessory (trap, SCM) Travels with the vagus nerve, but originates lower.
- X Vagus and IX glossopharyngeal nerve.
- CN VIII, vestibulocochlear.
NUCLEI OF THE MEDULLA
in the brainstem motor is medial and sensory is lateral. -HYPOGLOSSAL: CN XII, tongue
- AMBIGUOUS: CNs IX and X
- CUNEATAS: arms, neck
- GRACILIS : legs, trunk
- SPINAL OR MAIN SENSORY NUCLEUS: CN V synapses onto this.
- SOLITARY: cardiovascular info, taste,
- INFERIOR OLIVARY: connects to cerebellum
Where is the pyramidal decussation? or where is the corticospinal cross-over?
caudal end of the medulla
Where does POSTERIOR COLUMNS decussate?
(Sensory information) cross over from R side of the SC to the L of cortex with synapses at the GRACILE and CUNEATE NUCLEI and become MEDIAL LEMNISCUS (called MEDIAL LEMNISCUS from there to the cortex)
Where does the SPINOTHALAMIC system crosses over?
within the SC
BLOOD SUPPLY TO THE MEDULLA
Branches of the vertebral arteries:
- Anterior and posterior inferior cerebellar arteries.
- Anterior spinal artery.
External features of the PONS
- Basilar Pons
- Pontine Tegmentum
BASILAR PONS
- Anterior portion.
- MIDDLE CEREBELLAR PEDUNCLES: fibers extend transversely to the cerebellum.
PONTINE TEGMENTUM
Contains CN nuclei of:
- TRIGEMINAL (V), ABDUCENS NUCLEUS (VI), FACIAL NUCLEUS (VII), VESTIBULAR NUCLEI (VIII).
- Raphe nuclei: part of the reticular formation.
ANTERIOR SURFACE OF THE PONS
-MIDDLE CEREBELLAR PEDUNCLE: big pile of fibers connecting to the cerebellum. Transverse fibers. Shallow median groove.
POSTERIOR SURFACE OF THE PONS
- Covered by the cerebellum.
- SUPERIOR and MIDDLE CEREBELLAR PEDUNCLE.
- Forms the floor of the 4th ventricle.
LOCUS COERULEUS
PONS NUCLEI: -projects to the limbic system, hypothalamus, limbic system and cortex.
PONS SENSORY NUCLEI
MESENCEPHALIC (CN V): jaw reflex, spindles.
MAIN SENSORY (CN V): somatosensory head
KEY NUCLEI IN THE PONS
V, VI, VII -CN V brings in lots of sensory information
PONS MOTOR NUCLEI
- MOTOR NUCLEUS (CN V): mastication
- ABDUCENS (CN VI): eye movement.
- MOTOR NUCLEUS (CN VII): facial movements.
BLOOD SUPPLY TO THE PONS
basilar artery and its branches: -paramedian -short and long circumferential.
Where are the synapses of the DORSAL COLUMNS?
at the GRACILE and CUNEATE nucleus in the medulla.
How are the DORSAL COLUMNS called after they synapse at the GRACILE and CUNEATE nucleus in the medulla?
From that point on they are called MEDIAL LEMINSCUS or the GRACILE and CUNEATE fasciculi.
3 MAIN FUNCTIONAL REGIONS OF THE MIDBRAIN
- CRUS CEREBRI
- SUBSTANTIA NIGRA
- INTERMEDIATE ZONE
CURUS CEREBRI
PONS
- Anterior portion, descending fiber bundles.
- Cerebral peduncles; corticobulbar, corticospinal tracts.
- Other descending pathways tracts
SUBSTANTIA NIGRA
PONS Connects with basal ganglia. -PARS COMPACTA: [dopamine (degenerates in Parkinson’s)] -PARTS RETICULATA: [GABA output to thalamus]
INTERMEDIATE ZONE
PONS: contains various nuclei.
- CN III root.
- RED NUCLEUS: Flexion movements of the head neck and arms. (more prominent in cats). Signals from brainstem to muscles.
- PERIAQUEDUCTAL GRAY MATTER: opioids NRs. key in affective and emotional responses to pain. -
TECTUM (dorsal portion):
- Superior COLLICULUS: visual reflex, helps coordinate eye and head movement -Inferior COLLICULUS: auditory reflex center. inputs from medulla and pons. Output to thalamus related to coordinating movements to sounds.
- SPINOTHALAMIC TRACT
- TEGMENTUM: part of the reticular formation involved in autonomic and visceral processing.
