BCN Chapter 20

Question 1

What are the functions of the reticular formation?

Answer 1

Integrate CN reflexes
Participate in conduction and modulation of slow pain
Influence voluntary movements (Pontine and medullary levels)
Regulate autonomic nuclei (Hypothalamus)
Associated with diffuse modulating systems
Integrate basic functions (sleep, respiration)
Activation for cerebral cortex

Question 2

Where do afferent connections to the reticular formation come from?

Answer 2

Spinal cord (via anterolateral quadrant)
Cranial nerves (trigeminal, cochlear, and vestibular, Weak connections with CN 9 and 10)
Cerebellum
Forebrain (hypothalamus, thalamus, basal ganglia)

Question 3

What is the reticular efferent connections associated with?

Answer 3

CN activity
Slow pain
Voluntary movement
ANS
Distribution of monoaminergic and cholinergic neurotransmitters
Respiration
Sleep
Cortical arousal/wakefulness

Question 4

What is the cranial nerve activity in the midbrain?

Answer 4

Vertical gaze and vergence

Question 5

What is the CN activity in the Pons?

Answer 5

Blinking
Horizontal Gaze
Mastication
Auditory reflex

Question 6

What is the CN activity in the Medulla?

Answer 6

Swallowing and coughing
Gagging and vomiting
Circulation and Respiration
Equilibrium

Question 7

What are 3 features of he diffuse modulating systems?

Answer 7

1. Relatively small number of neurons (10,000-15,000)
2. Axons are long and have innumberable branches (100,000 widely spread postsynpatic neurons)
3. Neurotransmitters are released into extracelluar fluid

Question 8

What are the groups of nuclei in the diffuse modulating system? 3 in brainstem, 1 in forebrain

Answer 8

Brainstem
-Locus Ceruleus (norepinephrine) 
-Raphe (serotonin)
-Ventral Tegmental (dopamine)
Forebrain
-Basal nucleus of Meynert (cholinergic)

Question 9

Give the basic functions the the nuclei.

Answer 9

Locus Ceruleus - Regulation of attention, cortical arousal, sleep-wake cycle, learning, memory, anxiety, and mood
Raphe - Modulation of slow pain, sleep wake cycle, control of mood, and certain emotional behavior (mainly aggression)
Ventral Tegmental - Reward and pleasure fuctions
Basal Forebrain - Cortical excitability, memory, and learning

Question 10

What levels innervate muscles for respiration?

Answer 10

C3-4 - diaphragm via phrenic nerve

T1-10 - Inetercostals via intercostal nerves

Question 11

Where is the rhythmic activation of the lower motor neurons for respiration controlled by?

Answer 11

Bilaterally in ventrolateral medulla

near nucleus ambiguus at caudal part of 4th ventricle

Question 12

The respiratory center receives input from chemoreceptors that sense CO2 and O2 blood levels and send information via what cranial nerves?

Answer 12

Glossopharyngeal and vagus

Question 13

What is a major function of the pneumotaxic center in the dorsolateral tegmentum of rostral pons?

Answer 13

Coordinates breathing with chewing, swallowing, speaking

Question 14

What happens in respiration with damage to bilateral diencephalon?

Answer 14

Cheyne-Stokes breathing

Hypernea alternates with apnea

Question 15

What happens in respiration with damage to periaqueductal gray and adjacent paramedian reticular formation?

Answer 15

Central Neurogenic Hyperventilation

Sustained rapid deep hyperpnea

Question 16

What happens in respiration with damage to dorsolateral tegmentum at rostral pontine level?

Answer 16

Apneuristic breathing
(prolonged inspiration alternating with prolonged expiration)

Question 17

What happens in respiration with damage at the midpontine level?

Answer 17

Cluster breathing

3-4 rapid deep breaths alternating with period of apnea

Question 18

What happens in respiration with damage of dorsomedial retcular formation in caudal pons/rostral medulla?

Answer 18

Ataxic breathing

respiration is irregular and of uneven depths

Question 19

What happens in respiration with damage to bilateral ventralolateral medulla at level of centers or projects in caudal medulla or spinal cord?

Answer 19

Respiratory arrest

Question 20

What are the 2 stages of sleep

Answer 20

REM

NREM

Question 21

What happens in REM sleep?

Answer 21

Decreased muscle tone (except diaphragm & ocular)
muscle twitches
fluctuations in BP
TPR
Miosis
engorgement of sexual organs
Dreaming (visual events)
EEG looks like your awake

Question 22

Where does REM sleep occur?

Answer 22

Dorsolateral pontine RF

Question 23

What happens in NREM sleep?

Answer 23

Decreased neuronal activity
reduced body movement
decreased HR, and BP
Dreaming (less visual, more up to date)
looks like your asleep on EEG

Question 24

Where does NREM sleep occur and what happens if destroyed?

Answer 24

Anterior hypothalamic nucleus (preoptic area)

Insomnia

Question 25

What neurons/ areas are active during wakefulness?

Answer 25

All of them

Noradrenergic, Serotonergic, Cholinergic, Dopaminergic

Question 26

What neurons/areas are active during REM sleep?

Answer 26

Cholinergic

Question 27

What neurons/areas are active during sleep?

Answer 27

Dopaminergic

Question 28

Which part of the hypothalamus induces sleep/arousal

Answer 28

Sleep - Anterior part

Arousal - Posterior part

Question 29

What is the difference between narcolepsy and normal sleep?

Answer 29

Narcolepsy begins in REM

Question 30

What is the ARAS?

Answer 30

Ascending Reticular Activation System

• Monoaminergic and cholinergic diffuse modulatory nuclie and posterior hypothalamus
• responsible for arousal and wakefulness

Question 31

Where does the ARAS run?

Answer 31

Funnels through the paramedian midbrain reticular formation and divides into dorsal and ventral routes in the diencephalon

Question 32

Where is the lesion that results in a coma?

Answer 32

Rostral midbrain (interupts ARAS)
-Lesions in medulla or pons doesn't affect arousal or wakefulness