Brainstem Overview and Cranial Nerve Nuclei Flashcards
What is the brainstem
- Part of brain lying between spinal cord, cerebellum and cerebral hemisphere
What makes up the brainstem?
- medulla
- pons
- midbrain
What are the main brainstem structures?
- Nuclei for 10 of 12 pairs of cranial nerves
- Controls eye movements (3rd, 4th and 6th Cranial nerves
- Areas vital in the control of respiratory and cardiovascular systems
- Autonomics nervous system nuclei
- Several ascending and descending tracts connecting spinal cord to cerebral cortex and cerebellum
Describe the position of grey matter in the spinal cord vs the brainstem
Spinal cord = more vertical
Brain stem = more horizontal
What are the 7 main afferent input and efferent output pathways and their positioning in the brainstem?
- Special sensory afferent (SSA)
- General sensory afferent (GSA)
- General visceral afferent (GVA)
- Special visceral afferent (SVA)
- General visceral efferent (GVE)
- Special visceral efferent (SVE)
- General somatic efferent (GSE)
What is the arrangement of function in the brainstem of:
GSE
- GSE (somatic motor)
- Hypoglossal nucleus – innervates tongue
What is the arrangement of function in the brainstem of:
SVE
- SVE (visceral motor)
- Nucleus ambiguous
- Swallowing, speech, heart rate control
- Nucleus ambiguous
What is the arrangement of function in the brainstem of:
GVE
- GVE (autonomic motor)
- Dorsal motor nucleus of the vagus (CN X)
- GI and respiratory control
- Inferior salivatory nucleus (CN IX)
- Dorsal motor nucleus of the vagus (CN X)
What is the arrangement of function in the brainstem of:
GVA
- Solitary nucleus
- cardiovascular and respiratory
What is the arranagement of function in the brainstem of:
SVA
- Solitary nucleus
- Taste
What is the arranagement of function in the brainstem of:
GSA and SSA
- GSA and SSA (somatic sensory)
- Spinal nucleus
- Vestibular nuclei
- Vestibular nuclei
What are the three major tracts of the medulla?
- Corticospinal tract
- Medial meniscus
- Medial longitudnal fasiculus
Desribe the corticospinal tract in the brainstem
- Tract decussates just below the pyramids
- Controls voluntary movement
- Brainstem lesion leads to contralateral UMN paralysis
Describe the medial meniscus pathway in the medulla
- Originates from dorsal column nuclei
- Transmit information on about conscious proprioception and vibratory stimuli to thalamus
- Brainstem lesion leads to contralateral loss of joint proprioception
Describe the medial longitudnal fasiciculus in the medulla
- Ascending tracts originate from lateral, medial & superior vestibular nuclei and project to pons
- Information about head position sent to cranial nerves
- Descending fibres originate from medial vestibular nuclei and project to cervical spinal cord (vestibulospinal tract)
What are the major nuclei of the medulla?
- Reticular Formation
- Nucleus gracilis and cuneatus
- Spinal nucleus of CN V
- Cochlear, Vestibular nuclei
- Motor nuclei
What is the function of the reticular formation in the medulla?
- Modulation of sensory transmission to cortex
- Regulation of motor activity
- Autonomic regulation
- Sleep wake cycle/emotional behaviour
What is the function of the nucleus gracilis and cuneatus in the medulla?
- Receive information from dorsal columns
- Transmit information on conscious proprioception and vibratory stimuli to thalamus
What is the function of the spinal nucleus of CN V?
pain and temperature information from the head
What are the motor nuclei of the medulla?
hypoglossal
nucleus ambiguous