Brainstem Flashcards
Midbrain cranial nerves (CN)
CN III CN IV
Pons CN
CN V, VI, VII, VIII
Medulla CN
CN IX, X, XI, XII
superior cerebellar peduncles
almost exclusively efferent. Efferent axons project via thalamic nuclei to cerebral cortex
middle cerebellar peduncles
entirely afferent. Pontine nuclei integrate information from most areas of cerebral cortex
Inferior cerebellar peduncles
Both afferent and efferent. Afferents from spinal cord, vestibular apparatus and inferior olivary nucleus. Efferents project to vestibular nuclei and reticular formation
Tectum (posterior)
Tectum includes structures involved in reflexive control of intrinsic and extrinsic eye muscles and in movements of the head
Tectum structures
Superior and inferior colliculi, cerebral aqueduct and spinothalamic tract
Tegmentum: Anterior structures
Red nucleus, substantia nigra, corticospinal tracts and oculomotor nerve
The postural spinal tracts synapse at the
pons
Cerebral peduncles
Descending tracts from the cerebral cortex
Pretectal area (tectum)
Pupillary, consensual, and accommodation reflexes of the eye. Pupil control with light. If you have a problem with tectum, the pupils won’t dilate or constrict
Superior colliculi
Reflexive eye and head movements
Inferior colliculi
Relay auditory information from the cochlear nuclei to the superior colliculus and to the medial geniculate body of the thalamus
Periaqueductal gray area (tegmentum)
Pain suppression
Somatic and autonomic reactions to pain, threats, and emotions
Elicits fight-or-flight reaction
Vocalization during laughing and crying
Two production areas
Ventral tegmental area (VTA) and substantia nigra
Activation of VTA affects
cerebral areas, assisting in motivation and decision making.
nucleus accumbens, producing feelings of pleasure and reward
Ventral tegmentum neurotransmitter
dopamine
Pedunculopontine nucleus neurotransmitter
acetylcholine
Raphe nuclei neurotransmitter
serotonin
Raphe nuclei function
Effect on mood
Descending pain inhibition
Locus coeruleus and medial reticular zone neurotransmitter
Norepinephrine
Locus coeruleus function
Ability to direct attention
Inhibition of spinothalamic information
Medial reticular zone
Autonomic functions: respiratory, visceral, cardiovascular
Pons
Pons processes motor information from the cerebral cortex and forwards the information to the cerebellum
Spinal tracts in pons
Motor tracts are anterior and sensory are posterior just like the spinal cord
Most cranial nerve nuclei are in the dorsal section
Hypoglossal nucleus
Dorsal motor nucleus of the vagus
Solitary nucleus (involved in taste) (CN VII, IX, and X)
Vestibular nuclei
Cochlear nucleus
Ventral section
Nucleus ambiguus (CN IX and X)
Inferior medulla (anterior region)
Corticospinal tract form the pyramids (pyramidal decussation)
Dorsal column tracts
Nucleus gracilis and nucleus cuneatus
Decussate to medial lemniscus
Medial longitudinal fasciculus location
inferior medulla
Pyramidal lesions of medulla, what CN would be affected?
Oculomotor in the midbrain
Abducens in the caudal pons
Hypoglossal on the medulla
Reticular Activating System
A diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness.
Consciousness
Awareness of self and surroundings
Consciousness system
Governs alertness, sleep, and attention
Medical procedures that affect the RAS
anesthetics, melatonin and substance abuse
Descending reticular pathways
Integrates sensory and cortical information
Regulates somatic motor activity, autonomic function, and consciousness
Modulates nociceptive (pain) information
Major reticular nuclei are as follows
Ventral tegmental area (VTA)
Pedunculopontine nucleus (PPN)
Raphe nuclei
Locus ceruleus and medial reticular area
