Brainstem

Question 1

What is the Brainstem

Answer 1

A densely packed region with many vital structures

Question 2

What vital structures make up the brianstem

Answer 2

Long ascending sensory and descending motor
pathways
 Specific nuclear groups, including nuclei of cranial
nerves
 Central core occupied by the crucially important
“reticular formation”
 Monoamine neurotransmitter pathways arise
within brain stem
 Connecting cerebellar peduncles
 Descending autonomic system pathways

Question 3

What variety of functions does the Brainstem control

Answer 3

Motor Activities
Respiration
Cardiovascular Activities
Monoamine Systems

Question 4

What are monaamine Systems

Answer 4

sleep-wake cycles, feeding behaviors, neuroendocrine regulation, reward mechanisms
-Serotonin, noadrenaline, dopamine systems

Question 5

What are the most common brain stem lesions

Answer 5

Vascular pathology
Demyelinating diseases
neoplasms

Question 6

Brainstem vascular pathology (CVA)

Answer 6

ex. posterior inferior cerebellar artery (PICA) branch from the vertebra-basilar arteries of the circle of willis

Question 7

Demylenating diseases that affect the brainstem

Answer 7

Multiple Sclerosis

Question 8

Neoplasms in the BRainstem

Answer 8

Glial Cell Neuroma (astrocytoma)

Question 9

What are the major ascending Brainstem Pathways

Answer 9

Ascending 
 Spinal lemniscus 
[Spinothalamic tract] 
 Medial lemniscus (ML) 
[DC/ML tract] 
 Trigeminal lemniscus 
 Lateral lemniscus 
(auditory) 
 Reticular Formation 
system 
 Inferior and superior 
cerebellar peduncles 
 Medial longitudinal 
fasciculus[MLF]

Question 10

What are the major Descending Brainstem Pathways

Answer 10

Descending
 (UMN) 
 Corticospinal tract 
 Corticobulbar tract 
 Corticopontine tract 
 Rubrospinal tract 
 Tectospinal tract 
 Vestibulospinal tract 
 Reticulospinal tract 
 Medial longitudinal 
fasciculus [MLF]

Question 11

What does the spinal lemniscus pathway control

Answer 11

pain, temperature, simple
touch from body
SENSORY

Question 12

What does the medial lemniscus pathway control

Answer 12

simple and complex touch, proprioception, vibration from the body
SENSORY

Question 13

What does the trigeminal lemniscus pathway control

Answer 13

Sensory from the face and neck

Question 14

What does the MLF control

Answer 14

coordinating head-eye movements>connecting superior colliculus, CNs III, IV (midbrain) and VI (pons) with VIII vestibular N (pons medulla junction) with cervical spinal cord motor nuclei

Question 15

corticospinal, corticobulbar, and corticopontine pathways control

Answer 15

Direct Pyramidal MOtor

Question 16

Rubrospinal, tectospinal, vestibulospinal,

reticulospinal

Answer 16

indirect extrapyramidal motor

Question 17

MLF motor

Answer 17

vestibule-ocular integration, connects cn III, IV, VI with VIII and spinal fibers for head and neck coordination

Question 18

External Brain Stem Anatomy

Answer 18

Ventral [Anterior]

Medulla 
 Pyramid 
 Olive 
 Pyramid 
decussation 
 CN IX, X, XI, XII 

 Pons 
 Basal pons 
 CN V, VI, VII, VIII 
 
Midbrain 
 Crus cerebri of 
cerebral peduncle 
 CN III 
 Note: CN IV is 
dorsal (posterior)

Question 19

External Brainstem Anatomy

Answer 19

 Dorsal [Posterior] 
Medulla 
 Gracile tubercle 
 Cuneate tubercle 
 Hypoglossal triangle 
 medial 
 Vagal triangle 
 lateral 
 Lower IV ventricle 
 Inferior cerebellar 
peduncle (CP) 

Pons
 Mid-Upper IV
ventricle
 Middle CP

Midbrain 
 Inferior (auditory) & 
superior (vision) 
colliculi 
 CN IV (exits dorsally 
& wraps around 
ventrally) 
 Superior CP

Question 20

Internal Neuroanatomy

Answer 20

Within the brainstem are all ascending and descending Pathways
and
Cranial Nerve Nuclei

Question 21

Cranial Nerve Nuclei within the Brainstem

Answer 21

Sensory-usually 2nd order neurons
Motor-origin of cranial nerve LMN’s
Parasmpathetic preganglionics CN III, VII, IX, X

Question 22

Brain Stem Lesions

Answer 22

A single lesion commonly damages several structures
 Afferent or efferent components of the CN nuclei
 innervating ipsilateral face structures
 Long descending motor and ascending sensory
pathways  innervating contralateral body
structures causing hemiplegia and hemisensory
loss

Question 23

Vascular ischemic lesions often attack

Answer 23

medial vs, lateral and dorsal va, ventral areas of brainstem

Question 24

Medial brainstem lesions generally affect

Answer 24

1.Corticospinal Tract–contralateral hemiplegia
or
2. Medial Lemniscus– position and vibration sensory loss

Question 25

Lateral brainstem lesions often involve

Answer 25

``` 1. Spinothalamic tract • Loss of contralateral body P/T 2. Sympathetic fibers • Ipsilateral Horner’s syndrome 3. Spinal T/N of V • Loss of face P/T ipsilaterally 4. Vestibular nuclei • Nystagmus 5. Cerebellar connections • Ataxia of ipsilateral limbs ```

Question 26

Basilar (Ventral) Section (FRONT 1/2 of Brainstem)

Answer 26

Motor System Structures Descending UMN axons Motor Nuclei (substantia nigra, pontine nuclei, inferior olive) Pontocerebellar axons

Question 27

Tegmentum (Dorsal) Back 1/2 of Brainstem

Answer 27

Sensory Nuclei CN nuclei Reticular Formation MLF Midbrain Tectum (Pretectal Area, superior colliculi and inferior colliculi)

Question 28

Ventral Tacts

Answer 28

corticobulbar, corticoreticular corticopontine, corticospinal, Red Nucleus and Inferior olive

Question 29

Dorsal Tracts

Answer 29

Spinothalamic, Medial Leminscus(DC/ML), Spinocerebellar | Tectum and Dorsal Column Nucleus

Question 30

Lower Caudal Medulla

Answer 30

1.Nucleus Gracilis and Fasciculus Gracilis ventral medial 2.Nucleus Cuneatus and Fasciculus Cuneatus ventral medial 3.Spinal Nucleus of the Trigeminal Nerve and Spinal Tract of the Trigeminal nerve 4.Posterior Spinocerebellar tract 5.Anterior Spinocerebellsar Tract, 6.Rubrospinal Tract, 7.Descending Sympathetic Tract 8.Spinothalamic Tract 9.MLF 10.Trigeminal Lemniscus 11.Medial Lemniscus 12.Corticospinal Tract in the pyramid

Question 31

Upper /open Medulla

Answer 31

1. Hypoglossal Nucleus 2.Dorsal motor nucleus of vagus 3. Solitary Nucleus 4. Vestibular Nucleus 5. Lateral Cuneate Nucleus 6. Spinal Nucleus of trigeminal Nerve 7. Spinal Tract of Trigeminal Nerve 8. Descending Sympathetic Tract 9. Nucleus Ambiguus 10. Spinothalamic Tract 11. Raphe Nuclei 12. MLF 13. Medial Leminscus 14. Trigeminal lemniscus 15. Inferior Olivary Nucleus 16. Corticospinal tract in pyramid 17. CN XII--Hypoglossal CN X-trigeminal 18. IV ventricle 19. Inferior Cerebellar Peduncle