Chapters 14-15

Question 1

The cranial nerve nuclei are found where?

Answer 1

Brainstem

Question 2

Many nerve tracts, including the corticospinal tract, and the pyramidal decussation, are found where?

Answer 2

The brainstem

Question 3

What are the 4 main groups of things found in the brainstem?

Answer 3

1) Cranial nerve nuclei and related structures
2) Long tracts
3) Cerebellar circuitry
4) Reticular formation and related structures

Question 4

Give 2 examples of long tracts found in the brainstem

Answer 4

1) Corticospinal tract
2) Somatosensory pathways

Question 5

Give examples of things controlled by the “reticular formation and associated structures” category of brainstem structures

Answer 5

Brainstem nuclei and neurons that coordinate many of our vital functions such as :
1) Ex/motor control systems
2) Posture
3) Respiration
4) Cough, hiccup, sneeze, shiver
5) N/v
6) Autonomic control including HR and BP

Question 6

1) What is the Medial Longitudinal Fasciculus (MLF)?
2) Fibers from what 2 nuclei ascend here?

Answer 6

1) Heavily myelinated pathway connecting vestibular nuclei with nuclei involved with extraocular movements.
2) Medial and superior vestibular nuclei

Question 7

Fibers from the medial and superior vestibular nuclei ascend in the MLF to what 3 nuclei to mediate vestibulo-ocular reflexes?

Answer 7

Oculomotor (3), trochlear (4) and abducens (6) nuclei

Question 8

List and describe the long tracts of the brainstem

Answer 8

1) Corticospinal and corticobulbar: nerves from cortex to brainstem
2) Somatosensory pathways (posterior columns): vibration, proprioception and fine touch
3) Spinothalamic tract: antero-lateral pain, temperature, and crude touch
4) Descending sympathetic pathway: runs through lateral brainstem; damage to this causes Horner’s Syndrome

Question 9

What tracts are nerves that run from the cortex to the brainstem?

Answer 9

Corticospinal and corticobulbar

Question 10

What tract is responsible for pain, temperature, and crude touch?

Answer 10

Spinothalamic tract (antero-lateral)

Question 11

What pathway runs through lateral brainstem? What does damage to this cause?

Answer 11

Descending sympathetic pathway; Horner’s Syndrome

Question 12

What pathways are responsible for vibration, proprioception and fine touch?

Answer 12

Somatosensory pathways (posterior columns)

Question 13

1) What is the reticular formation?
2) What does its rostral end do?
3) What does its caudal end do?

Answer 13

1) Central core of nuclei that runs through the entire length of the brainstem
2) Maintain an alert conscious state.
3) Works with cranial nerve nuclei and the spinal cord to carry out motor reflex and autonomic functions

Question 14

What 2 things work with the caudal end of the reticular formation?

Answer 14

Cranial nerve nuclei and the spinal cord

Question 15

1) What is the end goal of the rostral end of the reticular formation?
2) What is the end goal of the caudal end of the reticular formation?

Answer 15

1) Maintain an alert conscious state.
2) Carry out motor reflex and autonomic functions

Question 16

In Locked-In-Syndrome:
1) Motor function is ________
2) Sensation and cognition are ________
3) What two tracts are affected?

Answer 16

1) Absent
2) Intact
3) Corticospinal and corticobulbar

Question 17

True or false: Locked-In-Syndrome is a type of coma

Answer 17

False; they’re different

Question 18

1) What usually causes locked-in-syndrome?
2) Why exactly can’t they move?

Answer 18

1) Infarct in the ventral pons, affecting the corticospinal and corticobulbar tracts.
2) These tracts being affected means the spinal cord and cranial nerves receive no input from the cortex

Question 19

Regarding locked-in-syndrome:
1) What pathways and systems are spared? What does this cause?
2) Why are eye movements spared?
3) Is it the same as a coma?

Answer 19

1) Sensory pathways and arousal systems in brainstem are spared, so patients are aware and able to feel, hear, and understand.
2) Their control center is in the rostral midbrain
3) No

Question 20

What forms the consciousness system?

Answer 20

The fronto-parietal association cortex with the arousal circuits in the upper brainstem.

Question 21

List the 3 processes that control the levels of consciousness and what’s involved with each

Answer 21

1) Alertness: normal functioning of the brainstem and arousal circuits
2) Attention: same circuits as above plus the frontoparietal association cortex
3) Awareness: a combination of multiple higher order systems from different regions of the brain into a summary of mental activity that can be remembered at a later time

Question 22

1) List the 3 processes that help control the level of consciousness
2) Which of these involves a summary of mental activity that can be remembered at a later time?

Answer 22

1) Alertness, attention, awareness
2) Awareness

Question 23

True or false: Multiple interconnected arousal systems act in parallel to maintain normal consciousness

Answer 23

True

Question 24

Name the 5 arousal systems that maintain normal consciousness

Answer 24

1) Upper brainstem neurons
2) Reticular formation
3) Posterior hypothalamic neurons
4) Basal forebrain neurons
5) Neurons in the rostral and medial thalamic nuclei

Question 25

What activates the 5 arousal systems that maintain normal consciousness?

Answer 25

Reticular formation and related structures that receive input from sensory pathways

Question 26

1) What project to the reticular formation? 2) Why?

Answer 26

1) Numerous regions of the association cortex 2) So cognitive processes and emotions can lead to an increased level of alertness through this system.

Question 27

1) What is the major excitatory neurotransmitter in the CNS? 2) What does too much of this cause?

Answer 27

1) Glutamate 2) Huntington’s chorea

Question 28

What is referred to as "nature's valium"? Why?

Answer 28

GABA; it's inhibitory

Question 29

1) Meds that increase GABA are used to treat what 3 things? 2) What 4 arousal systems does it inhibit to promote deep sleep?

Answer 29

1) Anxiety, seizures, muscle spasms 2) Serotonergic, noradrenergic, histaminergic, and cholinergic arousal systems.

Question 30

What are the 3 primary functions of acetylcholine (Ach)?

Answer 30

1) Autonomic function 2) Stimulates receptors at NMJ to cause muscle contraction. 3) In CNS it helps with memory

Question 31

What is Myasthenia gravis and what does it lead to?

Answer 31

An autoimmune Ab block Ach receptors on skeletal muscle, leading to weakness

Question 32

1) What can dopamine cause? 2) What does it work on? 3) What can too much lead to? 4) What can too little lead to?

Answer 32

1) Feelings or pleasure, satisfaction and motivation. 2) Reward center. 3) Schizophrenia, increased energy/arousal, hallucinations 4) Parkinson’s Disease

Question 33

1) What are the two main functions of norepinephrine? 2) What does increased amounts cause? 3) What does too little cause?

Answer 33

1) Used in sympathetic response and functions in attention, cognition and BP. 2) Aggression 3) Depression, inattention/ADD

Question 34

1) What is also known as the "feel good” chemical? 2) Is it excitatory, inhibitory, or both?

Answer 34

1) Serotonin 2) Can have excitatory and inhibitory effects

Question 35

1) What does serotonin function in? 2) When is it markedly decreased?

Answer 35

1) Psychiatric symptoms like depression, anxiety, OCD, aggressive behavior and eating disorders. 2) During sleep

Question 36

1) What does increased amounts of serotonin do? 2) What can increase it?

Answer 36

1) Lift and brighten mood 2) Exercise and bright light

Question 37

What is histamine used to regulate?

Answer 37

Alertness and wakefulness

Question 38

1) Most histamine is found where? 2) In what? 3) What does it do here?

Answer 38

1) Outside of the CNS 2) Mast cells 3) Plays a role in immune responses and allergic reactions

Question 39

What are antihistamine medications used for and what do they often cause?

Answer 39

To treat allergies; often cause drowsiness

Question 40

What does REM stand for and what often happens in this stage?

Answer 40

Rapid eye movement; dreaming usually occurs

Question 41

1) What happens during N1-3 of sleep? 2) What is the sleep cycle and how often does it happen at night?

Answer 41

1) Nonrapid eye movement 2) REM, N1, N2, N3; repeats many times during the night

Question 42

What area of the brain is thought to contain sleep- promoting regions?

Answer 42

Medulla reticular formation

Question 43

What produces melatonin and in what pattern?

Answer 43

Pineal gland in a circadian pattern

Question 44

1) Define coma 2) What is it a dysfunction of?

Answer 44

1) Unarousable, unconsciousness with closed eyes > 1 hour 2) Upper brainstem reticular formation

Question 45

True or false: Lesions of parts of the brainstem outside the upper brainstem reticular formation do not typically affect consciousness.

Answer 45

True

Question 46

1) What can occur during coma? 2) What can cause comas? 3) What reflexes are still present?

Answer 46

1) Can still have vestibulo-ocular eye movements, but no purposeful movements. 2) Typically caused by catastrophic brain injury such as trauma or anoxia. 3) Brainstem reflexes (gag, corneal, v-o)

Question 47

When is consciousness typically spared?

Answer 47

If the reticular formation is spared

Question 48

1) What 3 things should you do when a patient is in a coma? (step 1) 2) What is the second step? 3) What is the third step? 4) What exam should then be done?

Answer 48

1) Always secure airway, ensure patient is breathing, and has normal circulatory function. 2) Establish IV access and give IV thiamine, glucose and naloxone. 3) Treat to reverse cause of coma, if known and able. 4) ** Pupils**, labs, head CT

Question 49

1) Define Akinetic Mutism, Catatonia 2) Is the patient awake? Can they respond? 3) What may cause it to improve?

Answer 49

1) Impaired frontal lobe and dopamine function, profound deficits in response to initiation 2) Patient appears fully awake and can track with eyes, but can not typically respond to commands, though sometimes may after a long delay. 3) Dopamine agonist

Question 50

Define dissociative state. What neurologically is wrong?

Answer 50

Non-responsiveness (but not unconscious) from severe emotional trauma, neuro exam is normal

Question 51

Patients with Akinetic Mutism, Catatonia display what?

Answer 51

Profound deficits in response to initiation

Question 52

Define brain death

Answer 52

Based on clinical exam: no evidence of forebrain or brainstem function; no sleep-wake cycles

Question 53

Define vegetative state

Answer 53

Unconscious state but can have sleep-wake cycles and other responses or reflexes mediated by the brainstem; no purposeful movement or meaningful speech, though may make sounds; incontinent.

Question 54

What does CNIII do? Through what pathways?

Answer 54

Pupillary control; parasympathetic and sympathetic pathways

Question 55

1) What can CNIII palsy lead to? 2) What commonly causes CNIII palsy?

Answer 55

1) Dilated pupils. 2) Aneurysm of p comm artery

Question 56

What is a pupillary reflex?

Answer 56

Constriction of pupils in response to light

Question 57

List the 6 steps of the parasympathetic pupillary light reflex

Answer 57

1) Light enters retina 2) Hits retinal ganglion cells 3) Sends message through optic tract which crosses at the optic chiasm 4) Fibers continue to the superior colliculus 5) After synapsing there, the axons continue to the Edinger–Westphal nuclei which contains the preganglionic parasympathetic neurons 6) These parasympathetic fibers travel bilaterally via the oculomotor nerves to the ciliary ganglia in the eye and then on to the pupillary constricting muscles causing the pupils to become smaller.

Question 58

A light shone in 1 eye will cause _______________ of both pupils because the information crosses

Answer 58

constriction

Question 59

List 4 causes of coma and what the pupils look like with each

Answer 59

1) Toxic and metabolic disorders: Normally (usually) 2) Midbrain lesion or herniation: Unilateral or bilateral “blown” pupil 3) Pontine lesion: Small, responsive to light bilaterally 4) Opiate overdose: Pinpoint pupils bilaterally

Question 60

What can cause Horner's syndrome?

Answer 60

Lesions anywhere along sympathetic pathway

Question 61

What is the triad of Horner's syndrome symptoms?

Answer 61

1) Ptosis 2) Miosis 3) Anhidrosis

Question 62

1) The medullary reticular formation contains what? 2) What is the pacemaker for respirations? 3) What do the phrenic nerve efferents do? 4) Lesions in the medulla can cause what?

Answer 62

1) Crucial respiratory circuits 2) Pre-Botzinger Complex in medulla= pacemaker for respirations 3) Control diaphragm during inspiration 4) Respiratory arrest and death

Question 63

1) What controls breathing? 2) What do these have numerous inputs to?

Answer 63

1) Circuits in medulla 2) To respiratory circuit, including peripheral chemoreceptors for blood O2 level and pH and stretch receptors in the lungs

Question 64

1) Where is the nucleus solitarius? 2) What is it? Where does it get input from?

Answer 64

1) In the medulla 2) Cardiorespiratory nucleus (controls heart rate and BP); receives inputs from baroreceptors in carotid body and aortic arch via CNs 9 and 10

Question 65

The _________________ system gives rise to many branches that supply the brainstem and cerebellum

Answer 65

vertebrobasilar

Question 66

What are the 3 functional regions of the cerebellum?

Answer 66

1) Lateral hemispheres 2) Intermediate hemispheres 3) Vermis and flocculonodular lobes

Question 67

1) What is the vermis of the cerebellum? 2) What is on either side?

Answer 67

1) Wormlike structure in the midline 2) Cerebellar hemispheres on each side of vermis

Question 68

Cerebellar inputs come from where?

Answer 68

1) All areas of the cerebral cortex, multiple sensory modalities including vestibular, visual, auditory, and somatosensory systems 2) Brainstem nuclei and the spinal cord.

Question 69

1) What does the cerebellum do? 2) What do lesions in it typically cause?

Answer 69

1) The cerebellum coordinates movements and participates in motor planning; different regions have different functions 2) Uncoordinated movements called ataxia.

Question 70

What do the inferior vermis and flocculonodular lobes of the cerebellum do?

Answer 70

1) Regulate balance (proximal trunk muscle control) 2) Interact with vestibular circuitry (vestibulo-ocular control)

Question 71

1) What do the anterior lobes of the cerebellum do? 2) What do the intermediate cerebellar regions do? 3) What do the lateral cerebellar hemispheres do?

Answer 71

1) Responsible for proprioception 2) Control distal limbs 3) Motor planning of distal extremities

Question 72

1) Deficits in coordination occur in what direction compared to cerebellar lesions? 2) What cerebellar lesions cause ataxia of the limbs? 3) What lesions bilaterally affect the trunk muscles?

Answer 72

1) Ipsilateral 2) Lesions lateral to the vermis 3) Medial lesions

Question 73

1) What is the cerebellum attached to? How? 2) What does it form the roof of?

Answer 73

1) It is attached to the dorsal pons and rostral medulla by 3 peduncles. 2) The 4th ventricle.

Question 74

Name 3 ways to test cerebellar function

Answer 74

1) Finger-nose-finger test 2) Finger tap test 3) Heel to shin test

Question 75

What do vermis or flocculonodular cerebellar lobe lesions cause?

Answer 75

Unsteady gait (trunk control, posture, balance)

Question 76

List the 3 functional regions of the cerebellum

Answer 76

1) Lateral hemispheres 2) Intermediate hemispheres 3) Vermis and flocculonodular lobe

Question 77

1) What are the functions of the lateral hemispheres of the cerebellum? 2) What motor pathways do they influence?

Answer 77

1) Motor planning for extremities 2) Lateral corticospinal tract

Question 78

1) What are the functions of the intermediate hemispheres of the cerebellum? 2) What motor pathways do they influence?

Answer 78

1) Distal limb coordination 2) Lateral corticospinal tract and rubrospinal tract

Question 79

1) What are the functions of the vermis and flocculonodular lobe of the cerebellum? 2) What motor pathways do they influence?

Answer 79

1) Proximal limb and trunk coordination AND balance and vestibulo-ocular reflexes 2) Proximal limb and trunk: Anterior corticospinal tract, reticulospinal tract, vestibulospinal tract, tectospinal tract -Balance and reflexes: Medial longitudinal fasciculus

Question 80

1) What part of the cerebellum is attached to the brainstem? 2) Where are the cerebellar tonsils found?

Answer 80

1) Ventral surface 2) Inferior surface

Question 81

What is the clinical significance of the cerebellar tonsils?

Answer 81

Can herniate through the foramen magnum in cases of masses, brain swelling, severely elevated ICP and compress the medulla causing death from impingement of the medullary respiratory centers.

Question 82

On midsagittal section, the white matter and gray matter of the cerebellum are called what?

Answer 82

Arbor vitae “tree of life”

Question 83

The ridges of the surface of the cerebellum are called what instead of gyri?

Answer 83

Folia (‘leaves”)

Question 84

What connect the cerebellum to the brainstem?

Answer 84

The peduncles: superior, middle and inferior

Question 85

True or false: All the information from the body to the brain passes through the brainstem.

Answer 85

True