9 - Brainstem & Cranial Nerves I Flashcards
What is the oldest part of the brain?
The Brainstem
What is another name for the mesencephalon?
Midbrain
What is the diencephalon made up of?
Hypothalamus and Thalamus
What are the functions of the brainstem?
- Conduit: Long tracts to or from the spinal cord pass through the brainstem
- Cranial nerve functions: sensory input, motor and parasympathetic motor output, brainstem coordinates reflexes involving them
- Integrative centers in the brainstem: sensorimotor integration, autonomic control, somatic/autonomic modulation
What does the dorsal (tectum) part of the brain contain?
cranial nerve nuclei and sensory reflex centres
What does the middle part (tegmentum) part of the brain contain?
ascending pathways & reticular formation (with integrating nuclei; descending sympathetic axons
What does the ventral part of the brain contain?
descending motor pathways e.g., corticospinal & corticobulbar tracts; rubrospinal, reticulospinal and vestibulospinal tracts arising in brainstem
Draw the brainstem and label the parts of it
http://img.medscapestatic.com/pi/meds/ckb/17/12017tn.jpg
Which part of the brainstem are each of these sections from?
- look at google docs
Midbrain - Pons - Open medulla - Closed medulla
Name the 12 cranial nerves in order.
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear (Auditory), Glossopharyngeal, Vagus, Accessory, Hypoglossal
What are the main functions of cranial nerves II-IV and where are they found
Auditory, visual and pupillary reflexes and with eye movements - Midbrain
What are the main functions of cranial nerves V-VIII and where are they found
Mastication, eye movement, facial expression, taste, blinking, salivation, lacrimation, equilibrium, audition - Pons
What are the main functions of cranial nerves VIII-XII and where are they found
Audition, salivation, taste, respiration, GI function, neck and shoulder function, tongue movements - Medulla
Which is more sensory and which is more motor? - lateral to medial
Sensory is lateral
Motor is medial
Which nerves are pure sensory, pure motor and mixed?
Pure sensory - I, II, VIII
Pure motor - III, IV, VI, XI, XII
Mixed sensory and motor - V, VII, IX, V
What are the 3 types of motor nuclei?
Somatic - project to skeletal muscle
Branchial - project to muscles from branchial arches, jaw movement, facial expression, motor to larynx and pharynx, neck and shoulder
Visceral - preganglionic parasympathetic fibres
Fill out the table on the google docs
* Important
Look at the google docs
What is the function of the Medial longitudinal fasciculus?
Connect the cranial nerve nuclei controlling eye movement and the vestibular nuclei
Extends the length of the brainstem
What is internuclear ophthalmoplegia?
Damage to the MLF, both eyes won’t look the same way, often occurs due to stoke (unilateral) or ms lesion (bilateral)
When does the MLF become the medial vestibulospinal tract?
In the spinal cord
What is the reticular formation?
Forms a core of interconnecting neurons - a meshwork
It acts to integrate and filter inputs - modulates motor systems
What are the different cell groups and their function in the reticular formation?
Lateral (sensory) - Afferent input from all senses
Medial (motor) - Efferent output to midbrain, cerebellum, hypothalamus, thalamus and spinal cord
Midline (modulatory) - Facilitatory or inhibitory, e.g pain filtering inputs
What are the modulatory systems in the reticular formation?
Nuclei with specific neurotransmitters that modulate activities
- Locus coeruleus (Noradrenaline)
- Raphe nuclei (Serotonin)
- Substantia Nigra and Ventral Tegmental Area (Dopamine)
- Pedunculopontine Nucleus (Ach)
Where is the diffuse modulatory system found?
Pedunculopontine & lateral dorsal tegmental nuclei of the brainstem - AcetylCholine is released
Modulates Cortical arousal (through thalamic projection) and movement
What is the role of monoamine dopamine and where is it released ?
Substantia Nigra - Control of movement
Ventral Tegmental Area - Organisation behaviour, focusing and attention
What occurs if there is a disturbance in the Substantia nigra?
Parkinsons
What deficit occurs if there is a disturbance in the Ventral tegmental area?
Schizophrenia, addiciton
Where is noradrenaline released?
Locus Coeruleus
What is the function of the locus coeruleus?
Sympathetic nervous system control centre activated by the hypothalamus
Descending fibres, ascending fibres, activates motor systems and inhibits pain
Where is Serotonin (5-HT) released from?
Raphe nuclei
What is the function of the Raphe nuclei? Where is it?
Rostrally - inhibits basal forebrain to produce arousal, cognition, mood
Caudally - modulates pain perception
Deficits - OCD, depression, anxiety, aggression
Midline nuclei
