Download The Brainstem

The Brainstem
October 30, 2013
Chapter 13: 509 - 513
Dr. Diane M. Jaworski
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Brainstem:
does more than just link
the spinal cord and cerebrum
• Autonomic control of blood pressure, heart rate,
respiration, pupil diameter and digestion
• Cranial nerves: sensory & motor control of head/neck
• Special sense nerves for hearing, balance, taste, vision
• Maintains consciousness!!!!!
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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
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Just like the Spinal Cord
Dorsal = Sensory
Pineal
gland
Midbrain
Pons
Medulla
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Just like the Spinal Cord
Ventral = Motor
Midbrain
Pons
Medulla
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© McKinley et al. A & P 2013
T
Medulla
Oblongata
H
Pons
T = Thalamus
H = Hypothalamus
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Medulla oblongata
• Autonomic nuclei:
- cardiovascular centers
- respiratory rhythmicity centers
- vomiting center
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© McKinley et al. A & P 2013
Medulla Oblongata
Pyramid
N cuneatus
N gracilis
Olive
Motor info crosses here
• Cranial nerves - VIII, IX, X, XI, XII
• Olivary nucleus (olive) - motor learning
• Pyramids - where corticospinal tract
(carries descending motor info)
crosses to opposite side of body
• Nucleus gracilis - leg
• Nucleus cuneatus - arm
sensory info from body
(except pain & temperature)
crosses after synapsing here
before going to the thalamus
• Trigeminal nucleus (CN V)
pain and temp from face
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© McKinley et al. A & P 2013
T
H
Pons
Pons
Medulla
Cerebellu
m
Cerebellu
m
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Pons
• Trigeminal nucleus (CN V) –
general sensations (not
pain) from the face
• Motor plan sent into
cerebellum for coordination
(this is what makes the big
bulge on the ventral pons)
• Tracts:
– Descending motor axons
from cortex and red nucleus
(in midbrain)
– Ascending sensory axons
from body AND face
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© McKinley et al. A & P 2013
Pons
• Cranial
nerves - V, VI, VII, VIII
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Cerebellar Peduncles
axons linking the cerebellum & brainstem
Inferior (ICP) - Unconscious proprioception info (what you are doing)
INPUT
Info from olivary nucleus (motor learning)
Middle (MCP) - Motor info from cortex for coordination (what you WANT to do!)
INPUT
Forms transverse fibers that give pons its shape
Superior (SCP) - To red nucleus & thalamus to correct motor actions
OUTPUT
(fix bad motor plan)
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Cerebellar Peduncles
Superior Cerebellar Peduncle
Middle Cerebellar Peduncle
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Transverse
Fibers
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© McKinley et al. A & P 2013
T
H
Midbrain
Pon
s
Medulla
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Midbrain
• Reticular activating system (RAS) - critical for maintaining
consciousness
• Substantia nigra - dopamine containing neurons that are part
of the basal ganglia (motor), die in Parkinson’s disease
• Red nucleus – arm flexion, damage results in a decerebrate
posture which is a poor clinical sign
• Cerebral peduncles – axons of descending motor neurons to
innervate the brainstem and spinal cord
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© McKinley et al. A & P 2013
Midbrain
• 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
Superior colliculus
Inferior colliculus
• Superior + Inferior Colliculi
= Tectum (“roof”)
• Superior colliculi
- visual tracking of objects
• Inferior colliculi
- auditory localization
• Cranial nerves - III, IV
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Most of the Neurotransmitters for the
Cerebrum are made in the Brainstem!
Dopamine from the
Substantia nigra
Involved in movement Parkinson’s disease,
drug cravings and
psychosis
Norepinephrine
Serotonin
Involved in sleep and
mood
Involved in control of
mood, sleep and feeding
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