BCN Chapter 20 Flashcards
What are the functions of the reticular formation?
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
Where do afferent connections to the reticular formation come from?
Spinal cord (via anterolateral quadrant)
Cranial nerves (trigeminal, cochlear, and vestibular, Weak connections with CN 9 and 10)
Cerebellum
Forebrain (hypothalamus, thalamus, basal ganglia)
What is the reticular efferent connections associated with?
CN activity Slow pain Voluntary movement ANS Distribution of monoaminergic and cholinergic neurotransmitters Respiration Sleep Cortical arousal/wakefulness
What is the cranial nerve activity in the midbrain?
Vertical gaze and vergence
What is the CN activity in the Pons?
Blinking
Horizontal Gaze
Mastication
Auditory reflex
What is the CN activity in the Medulla?
Swallowing and coughing
Gagging and vomiting
Circulation and Respiration
Equilibrium
What are 3 features of he diffuse modulating systems?
- Relatively small number of neurons (10,000-15,000)
- Axons are long and have innumberable branches (100,000 widely spread postsynpatic neurons)
- Neurotransmitters are released into extracelluar fluid
What are the groups of nuclei in the diffuse modulating system? 3 in brainstem, 1 in forebrain
Brainstem -Locus Ceruleus (norepinephrine) -Raphe (serotonin) -Ventral Tegmental (dopamine) Forebrain -Basal nucleus of Meynert (cholinergic)
Give the basic functions the the nuclei.
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
What levels innervate muscles for respiration?
C3-4 - diaphragm via phrenic nerve
T1-10 - Inetercostals via intercostal nerves
Where is the rhythmic activation of the lower motor neurons for respiration controlled by?
Bilaterally in ventrolateral medulla
near nucleus ambiguus at caudal part of 4th ventricle
The respiratory center receives input from chemoreceptors that sense CO2 and O2 blood levels and send information via what cranial nerves?
Glossopharyngeal and vagus
What is a major function of the pneumotaxic center in the dorsolateral tegmentum of rostral pons?
Coordinates breathing with chewing, swallowing, speaking
What happens in respiration with damage to bilateral diencephalon?
Cheyne-Stokes breathing
Hypernea alternates with apnea
What happens in respiration with damage to periaqueductal gray and adjacent paramedian reticular formation?
Central Neurogenic Hyperventilation
Sustained rapid deep hyperpnea
What happens in respiration with damage to dorsolateral tegmentum at rostral pontine level?
Apneuristic breathing (prolonged inspiration alternating with prolonged expiration)
What happens in respiration with damage at the midpontine level?
Cluster breathing
3-4 rapid deep breaths alternating with period of apnea
What happens in respiration with damage of dorsomedial retcular formation in caudal pons/rostral medulla?
Ataxic breathing
respiration is irregular and of uneven depths
What happens in respiration with damage to bilateral ventralolateral medulla at level of centers or projects in caudal medulla or spinal cord?
Respiratory arrest
What are the 2 stages of sleep
REM
NREM
What happens in REM sleep?
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
Where does REM sleep occur?
Dorsolateral pontine RF
What happens in NREM sleep?
Decreased neuronal activity reduced body movement decreased HR, and BP Dreaming (less visual, more up to date) looks like your asleep on EEG
Where does NREM sleep occur and what happens if destroyed?
Anterior hypothalamic nucleus (preoptic area)
Insomnia
What neurons/ areas are active during wakefulness?
All of them
Noradrenergic, Serotonergic, Cholinergic, Dopaminergic
What neurons/areas are active during REM sleep?
Cholinergic
What neurons/areas are active during sleep?
Dopaminergic
Which part of the hypothalamus induces sleep/arousal
Sleep - Anterior part
Arousal - Posterior part
What is the difference between narcolepsy and normal sleep?
Narcolepsy begins in REM
What is the ARAS?
Ascending Reticular Activation System
- Monoaminergic and cholinergic diffuse modulatory nuclie and posterior hypothalamus
- responsible for arousal and wakefulness
Where does the ARAS run?
Funnels through the paramedian midbrain reticular formation and divides into dorsal and ventral routes in the diencephalon
Where is the lesion that results in a coma?
Rostral midbrain (interupts ARAS) -Lesions in medulla or pons doesn't affect arousal or wakefulness
