Brainstem

Front 1

What are the brainstems main functions?

Back 1

Conveys sensory info to the cortex
Regulation of the autonomic N.S
Visual and auditory reflexes
Alertness and consciousness
Breathing
Functional composition of cranial nerves

Front 2

How do the cranial nerve nuclei develop?

Back 2

Align horizontally
Death of some neuroblasts in the cell columns or brainstem results in the creation of individual nerve nuclei

Front 3

Give the examples of efferent cranial nerve nuclei which give rise to axons that leave the brainstem

Back 3

General Somatic Efferent
III: 4 Extraocular muscles
IV: Superior oblique
VI: Lateral rectus
XII: Tongue muscles
(III/IV/VI are all from the oculogyric nuclei

Front 4

Give examples of general visceral afferent cranial nerves and the nucleus they travel to

Back 4

IX + X
From carotid body/ aortic region/ thorax/ abdomen
To Caudal part of nucleus tractus solitairus

Front 5

Give examples of Special Visceral Afferent cranial nerves and the nucleus they travel to

Back 5

VII: Anterior 2/3 of the tongue
IX: Posterior 1/3 of the tongue
X: Epilglottal taste buds
To the rostral part of nucleus tractus solitairus

Front 6

Give the general somatic afferent component to the trigeminal nerve including nuclei involved

Back 6

V1, V2, V3: Facial dermatomes for skin sensation
Proprioception: mesencephalic nucleus
Mechanoreceptors: Main/Chief nucleus
Nociception: Spinal nucleus

Front 7

Name the 4 ascending tracts

Back 7

Dorsal column- medial lemniscus
Spinothalamic
Trigeminothalamic
Spinocerebellar

Front 8

What does the median longitudinal bundle connect?

Back 8

1. Oculogyric nuclei 3/4/6 (close to midline)
2. Oculogyric and vestibular nuclei
3. Oculogyric nuclei, tectum and tectospinal tract
4. Pontine reticular formation

Front 9

What type of control is nucleus tractus solitairus involved with and where does it send axons to?

Back 9

Sends axons to visceral centres of the reticular formation
Preganglionic Autonomic N.S
Control:
Respiratory centres
Cardiovascular centres
Vomit reflex
Diaphragm through phreninucleus
(Controls some lower motor neurons too e.g in the vomit reflex need constriction of the abdomen wall

Front 10

What does the medial vestibulospinal tract control?

Back 10

Controls movement of the head neck and eyes in response to changes in posture

Front 11

Why must the median longitudinal bundle remain intact?

Back 11

To maintain conjugate eye movements
coordination

Front 12

What are the descending tracts?

Back 12

Corticospinal
Corticobulbar (goes to the brainstem- GSE + SVE)
Corticopontine (Cerebellum)
Hypothalamic efferent- control of ANS

Front 13

What is involved with the median column of the reticular formation?

Back 13

Median column = Raphe Nuclei
- Only neurons that use seretonin
- Spinal projection involved with analgesia in the dorsal horn and bladder control
- Rostral projection to the hypothalamus and cerebral cortex to modulate sleep and wake states and interacts with dopamine in schizophrenia

Front 14

What is invloved with the lateral columns of the reticular formation

Back 14

Origin of descending analgesia pathways
Axons to the reticular formation nuclei which form reticulospinal tracts involved in tone, posture and maintaining balance particularly during movement.
Also relay info to the cerebellum from the eyes and ears so the cerebellum can intergrate visual, auditory and vestibular info in motor coordination
Also involved in sleep and consciousness and cardiovascular control

Front 15

Name the monoamines involved in brainstem systems

Back 15

1. Seretonin (midline)
2. Noradrenaline- Locus coerulus- rostral pons projecting to the entire CNS, innervating the thalamus and hypothalamus (assoc with depression in cerebellar cortex)
- Lateral tegmental tract- spinal projection for continence, hypothalamus controls releasing factors
3. Dopamine- Substantia nigra- corpus striatum (parkinsons)
- Mesolimbic overactivity = shizophrenia
- Mesocortical underactivity = schizophrenia

Front 16

What are the steps involved in processing conjugate eye movements

Back 16

1. The horizontal gaze centre gives input to the abducens nucleus- gaze to the ipsilateral side
2. One subset of neurons projects directly to the ipsilateral lateral nucleus
3. Another subset of neurons in the abducens nucleus crossed the midline and travels to the medial longitudinal bundle to the contralateral oculomotor nucleus
4. The oculomotor neurons innervate the ipsilateral medial rectus and the eyes move to the contralateral side
5. Both eyes move in the same direction (left)

Front 17

Where is the horizontal gaze centre located?

Back 17

In the paramedian pontine reticular formation

Front 18

What kind of movement are the extra ocular muscles involved in?

Back 18

Fine eye movements- small motor untits

Front 19

To which nuclei do afferents send information to in fine eye movements?

Back 19

Trigeminal nuclei via connection with the opthalamic division of V
CN III + V are linked via the medial longitudinal bundle
Enables eyes movement in the dark

Front 20

What is the pupillary constriction reflex pathway?

Back 20

Retina
Pretectal area
CN III (preganglionic parasympathetic)
Ciliary ganglion
Constrictor pupillae

Front 21

What is the pupillary dilation pathway?

Back 21

Retina
Dorsolateral brainstem
T1 (sympathetic preganglionic)
Sympathetic chain
Superior cervical ganglion
Dilator pupillae

Front 22

What connects the left and right eyes in the consensual reflex?

Back 22

Pretectal area

Front 23

What is the reflex pathway involved with accommodation?

Back 23

Retina
Optic N. and optic radiation to occipital lobe
Area 19
Edinger westphal nucleus
CN III
Ciliary muscles, medial rectus and (via parasympathetic) sphincter pupillae

Front 24

What is convergence?

Back 24

The ability of the eyes to move towards each other to focus on near objects
Contraction of the medial rectus (L+R) and relaxation of lateral rectus (L+R)
Constriction of both pupils
Contraction of the ciliary muscle
Coordination by Medial longitudinal bundle

Front 25

What is the light reflex pathway?

Back 25

Retina
Parasympathetic N.S
CN III
Pupil constricts
Light on retina---- optic nerve
Superior colliculus
Tectobulbar/ tectospinal tracts
Cervical cord
Lower motor neurons to neck muscles
CN VII
Orbicularis occuli

Front 26

Blood supply of the brainstem?

Back 26

Vertebro- basilar system
3 groups of arteries come off:
Paramedian- Anterior spinal artery travels in the ventral fissure
Short circumferential
Long circumferential

Front 27

What causes lower red nucleus syndrome?

Back 27

Paralegion blood vessels
Disrupts motor function
Oculomotor fibres affected = restricted eye movements
Akinesia = parkinsonism
Contralateral spastic hemiplegia (corticospinal fibres)
Contralateral facial and hypoglossal paralysis (corticobulbar fibres)
Contralateral dystaxia (corticopontine tract)

Front 28

What are the symptoms of dorsolateral medullary syndrome of wallenburg?

Back 28

Nystagmus (Inf. vestibular nucleus)
Ataxia and ipsilateral asynergia (Inf. Cerebellar peduncle)
Ageusia (Nucleus tractus solitairus)
Ipsilateral analgesia and thermanesthesia of face (nucleus of trigeminal spinal tract)
Tachycardia and dyspnoea (Dorsal nucleus of vagus)
Horner's syndrome (central sympathetic pathway)
Contralateral analgesia (Lateral spinothalamic tract)
Ataxia and ipsilateral hypotonia (Ant. spinocerebellar tract)

Front 29

What is involved in syndrome of the mid pontine base?

Back 29

Motor function damaged
Ipsilateral hemiplasia
Affects outflow of trigeminal nerve = sensation loss
Loss of innervation of the muscles of mastication = jaw deviates to side of lesion
Hemiataxia and ipsilateral asynergia (middle cerebellar peduncle)
Contralateral spastic hemiparesis (corticospinal tract)
Ipsilateral dystaxia (Pontine nucleus)

Front 30

What is involved in Horner's syndrome?

Back 30

Nystagmus, speech and swallowing disorder
Long circumferential nerve affected (dorsolateral side of brainstem)
Lesion of Post. Inf. Cerebral artery
Cerebellar dysfunction
Ptosis and constriction of pupil