RETICULAR FORMATION Flashcards

1
Q

The term reticular formation refers to a mass of neurons and nerve fibers extending from the caudal medulla to the rostral midbrain and continuous with the________ of the subthalamus and__________of the thalamus.

A

zona incerta

midline, intralaminar and reticular nuclei

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2
Q

the reticular formation of the brain stem is divided into the following nuclear groups:

A

Median raphe: The neurotransmitter of most raphe nuclei is serotonin.

Paramedian reticular:lateral to the medial longitudinal fasciculus and the medial lemniscus

Medial reticular
Lateral reticular

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3
Q

Raphe nuclei of the medulla oblongata receives inputs from

A

spinal cord, trigeminal sensory nuclei (second-order sensory input), and the periaqueductal gray matter of midbrain.

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4
Q

The facilitatory input from the _________matter to the medullary raphe nuclei, and the inhibitory projections of the latter on _______constitute the anatomic substrate for the analgesic effect of electrical stimulation of the midbrain periaqueductal gray.

A

periaqueductal gray

spinothalamic neurons in the dorsal horn of spinal cord

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5
Q

It becomes evident from their connections that the caudal raphe nuclei are involved in ______mechanisms while the ________are part of the reticular activating system concerned with wakefulness, alertness, and sleep.

A

pain

rostral raphe nuclei

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6
Q

Descending projections from the medial group of reticular nuclei project to the spinal cord ____________

A

pontine and medullary reticulospinal tracts located in the ventral and lateral funiculi of the spinal cord

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7
Q

MEDIAN GROUP)

The _________ projections of this group of reticular nuclei suggest a role in motor control, whereas the ascending projections relate these nuclei to _____________

A

descending

consciousness and alertness

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8
Q

The ____________(paramedian reticular and reticulotegmental) receives inputs from the spinal cord (spinoreticular), cerebral cortex, and vestibular nuclei and project to the cerebellum.

A

paramedian group of reticular nuclei

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9
Q

The _______in the medulla and pons (parvocellularis and lateralis) constitute the receptive component of reticular nuclei.

A

lateral group of reticular nuclei

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10
Q

An expiratory center has been located experimentally within the ______of the medulla oblongata.

A

parvocellular reticular area

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11
Q

The involvement of the __________in Parkinson’s disease may explain the autonomic disturbances that occur in that disease.

A

parabrachial nucleus

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12
Q

Based on its connections, the_______ plays a role in integrating and gating activities of thalamic nuclei.

A

reticular nucleus

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13
Q

Cholinergic neurons are found in two locations

A

(1) rostral pons-caudal midbrain, and

(2) basal forebrain.

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14
Q

The _________ and the adjacent lateral dorsal tegmental nucleus lie within the tegmentum of the pontomesencephalic junction, dorsolateral to and overlapping the lateral margin of the superior cerebellar peduncle, between it and the lateral lemniscus.

They play roles in arousal and movement.

A

pedunculopontine reticular nucleus

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15
Q

Neurons of the pedunculopontine nucleus are affected in patients with _______

A

progressive supranuclear palsy

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16
Q

Dopaminergic neurons form small clusters at several brain loci. Many of these neurons are found in the _______ (ventral tegmental area of Tsai) and the _________

A

ventral tegmentum of the midbrain

adjacent substantia nigra (pars compacta).

17
Q

Noradrenergic neurons of the brain stem are divided into two major components.

The first is the norepinephrine system of the ___________The second is the ______________comprising another series of noradrenergic cell groups scattered in the pons and medulla (groups A1 to A7).

A

locus ceruleus (catecholamine neuron cell group A6)

lateral tegmental norepinephrine system,

18
Q

The rostral pontine and mesencephalic serotonergic raphe neurons project to the entire ________, whereas the caudal pontine and medullary serotonergic raphe neurons project to the ________

A

forebrain

cerebellum, medulla, and spinal cord

19
Q

The _________plays a role in psychiatric disorders (depression, obsession-compulsion, aggression, anxiety)

A

rostral raphe serotonergic system

20
Q

Inhibition of__________ in the raphe system leads to insomnia.

A

serotonin

21
Q

reticular formation functions

A

somatic motor, somatic sensory, visceral motor, and arousal and sleep functions.

22
Q

Somatic Motor Function: In general, the ________ exerts facilitatory influences, whereas the _____ exerts inhibitory influences.

A

pontine reticular formation

medullary reticular formation

23
Q

Somatic sensory: The analgesia produced by stimulation of the periaqueductal gray is mediated by facilitatory input from the periaqueductal gray to the _______

A

nucleus raphe magnus.

24
Q

Visceral Motor Function.

Stimulation of the __________in the medulla oblongata elicits an inspiratory response and depressor effect on the circulatory system

A

medial group of reticular nuclei

25
Q

A pontine reticular center (pneumotaxic center) which regulates respiratory rhythm has been identified in the area of _________ nuclei located dorsal to the motor nucleus of the trigeminal nerve.

A

parabrachial–Kölliker-Fuse

26
Q

Activity in the ascending reticular activating system is a ______ maintained by incoming afferent stimuli.

A

tonic one

27
Q

______plays a central role in selective awareness.

A

reticular nucleus

28
Q

phases of sleep:

A

(1) slow wave sleep and

(2) rapid eye movement (REM) or paradoxical sleep.

29
Q

SLOW WAVE SLEEP

A

Reduced muscle tone.
Drop in blood pressure, heart rate, and respiratory rate.
Synchronized slow EEG activity of high voltage; hence the name slow wave sleep.

30
Q
Stages of SLOW WAVE SLEEP
Stage I (drowsiness). This stage lasts from one to seven minutes. \_\_\_\_\_\_\_\_\_

Stage II (light sleep). Arousal in this stage needs more intense stimuli than in Stage I.

Stage III (moderately deep sleep). The EEG in this stage is characterized by the appearance of_______

Stage IV (deep sleep). Arousal from this stage requires strong stimuli.

A
  1. The individual is easily aroused in this stage.

2. slow, high voltage waves.

31
Q

Sleep walking, bed wetting, night terrors, and seizures are known to occur in ______

A

slow wave sleep.

32
Q

_______sleep is also known as desynchronized sleep, active sleep, dreaming sleep, fast wave sleep, and deep sleep. It constitutes 25% of sleeping time in adults

A

REM (PARADOXICAL) SLEEP

33
Q

Features of REM sleep

Marked _____, especially in neck muscles, hence head drop in people entering this state while sitting up in a chair.

Increase in ______irregular and rapid respiration.

Erection in males.

Teeth grinding.

Dreaming, hence the name dreaming sleep.

Rapid eye movements _______ hence the name REM sleep.

A

hypotonia

blood pressure and heart rate;

(50 to 60 movements per min),

34
Q

It is easier to _____a person from REM sleep than from stage IV slow wave (non-REM) sleep.

A

awaken

35
Q

The first REM phase occurs about ______after sleep onset and lasts ______. Subsequent REM phases recur every 1 to 2 hours.

A

90 minutes

about 10 to 15 minutes

36
Q

_________suppress REM sleep but have little effect on stage IV of non-REM (slow wave) sleep. On the other hand, _________(Valium, Librium) suppress stage IV non-REM sleep and have less effect on REM sleep.

A

Barbiturates and alcohol

benzodiazepines

37
Q

It is now established that the ascending reticular activating system and cortical arousal are mediated via two systems:

A ______ from the pedunculopontine and laterodorsal tegmental reticular nuclei to several thalam-ic nuclei (intralaminar, relay, reticular) and from there, via thalamocortical projections, to the cerebral cortex. This system is active during_______

An ________from locus ceruleus (norepinephrine), raphe nuclei (serotonin), tuberomammillary nucleus (histamine) directly (without passing through the thalamus) to the cerebral cortex. This system is active during _______ but not during REM sleep.

A

cholinergic system

wakefulness and REM sleep.

aminergic system

wakefulness