Download ANPS 019 Black 11-05

ANATOMY 019
BRAINSTEM
November 4, 2011
Chapter 14: 456 -462
BRAINSTEM: does more than just link the spinal cord and cerebrum
-contains control centers for blood pressure, heart rate, respiration, pupil diameter and digestion
-cranial nerves for sensory and motor control of head and neck
-additional cranial nerves for hearing, balance, taste, vision
--“special senses” not classified as autonomic or somatic
*smell has no connection to the brainstem
THE BRAINSTEM:
Controls the daily functions that keep you alive
You can live without a cortex; you can’t live without a brainstem!!
Main parts:
Midbrain: mesencephalon
Pons: metencephalon
Medulla: myelencephalon
JUST LIKE THE SPINAL CORD
DORSAL = SENSORY
VENTRAL = MOTOR
-ventral sides hold on the cranial nerves
MEDULLA OBLONGATA
Holds pacemaker neurons:
Autonomic nuclei:
-cardiovascular centers
-respiratory rhythmicity centers
-vomiting center
--monitors toxins, triggers cranial nerves that are responsible for swallowing, making do oppositeVOMIT
Holds cranial nerves- VIII, IX, X, XI, XII
Olivary nuclei (olive) - motor leering (repetition, like shooting a basketball
Pyramids: where coritcospinal tract (carries descending motor info crosses to opposite side of body)
Nucleus gracilis – leg
Nucleus cuneatus – arm
-Sensory info from body (except pain and temperature) crosses after synapsing here before going to the
thalamus
Trigeminal nucleus (CNV) pain and temp from face
PONS
How brainstem connects with cerebellum
Trigeminal nucleus (CN V) –sensations (not pain) from the face
-3 nucleuses, one in each section
Nuclei involved with respiration
Motor pain sent into cerebellum for coordination
Tracts:
-descending motor axons from cortex and red nucleus (in midbrain)
-Ascending sensory axons from body and face
Pons is protuberance with transverse fibers
Cranial nerves: V, VI, VII, VIII
Cerebellar Peduncles –big bundle of axons
Axons linking the cerebellum and brainstem
Inferior (ICP) input: unconscious proprioception (relationship of body in space) info from olivary nucleus
(motor learning)
Middle (MCP) Input: Motor info from cortex for coordination, forms transverse fibers that give pons its
shape
Superior (SCP) Output: TO red nucleus and thalamus to correct motor actions
Cerebellar Peduncles
Inferior peduncle, can’t be labeled
Only one blood vessel – gives blood supply to both sides
MIDBRAIN
Reticular activating system (RAS) –critical for maintain consciousness
-when this shuts down: lose consciousness
-decerebrate = brainstem injury = BAD
Substantia nigra – dopamine containing neurons that are part of the basal ganglia (motor), die in
Parkinson’s disease
Cerebral Peduncles Cortex:
Motor axons going to:
-Spinal Cord
-Brainstem cranial nerve nuclei
-Pons (then to cerebellum)
-Olivary nucleus (motor learning)
Red nucleus- innervates upper extremity flexor muscles
Cranial Nerves: III, IV
Superior and Inferior Colliculi = Tectum (“roof”)
Superior colliculi
-visual tracking of objects
Inferior Colliculi
-auditory localization
TRANSMITTER PROJECTIONS FROM THE BRAINSTEM TO THE CORTEX
Dopamine from the Substantia nigra
-Involved in movement- Parkinson’s disease drug cravings and psychosis
Norepinephrine from the Locus Ceruleus
-Involved in sleep and mood
Serotonin from the Raphe
-Involved in control of mood, sleep and feeding