Reticular Activating System Flashcards
You encounter a patient with an irregular heartbeat who also cannot sense pain. What region of the brain is most likely affected?
Reticular formation
Where is the raphe nuclei found?
Along the midline of medulla and midbrain.
It is important in maintaining wakefulness.
You are studying the function of raphe nuclei in mice. A lesion to the raphe nuclei will produce what symptoms in the mice?
The mice will not be wakeful and will most likely be in a permanent coma.
All sensory input that enters the brain via the medulla is also sent to neurons of what structure?
Reticular formation.
You are dozing off during class. Your professor then announces a pop quiz and you immediately wake up. Your wakefuless is caused by what region of the brain?
Reticular formation
Where does the reticular formation receive input from?
The cerebral cortex
What are the two zones of the reticular activating system?
Magnocellular
Parvocellular
What types of neurons are found in the magnocellular zone?
A specific type of neuron with long radiating dendrites.
What brain structures pick up information from the magnocellular zone?
Spinoreticular fibers
Sensory cranial nerves
Cerebellum
Hypothalamus
Basal nuclei
Cerebral cortex (premotor cortex)
Where do the long ascending/descending pathways of the magnocellular zone terminate?
Hypothalamus
Midline and intralaminar thalamic nuclei
Segments of spinal cord
Long ascending fibers from the magnocellular zone include … ?
Lower pons and medulla
What neurotransmitters are used in the magnocellular zone?
Serotonin
Norepinephrine
Dopamine
Serotonergic pathways originate in what brain structure?
Raphe nuclei
Where to serotonergic pathways terminate?
Substantia gelatinosa (pain)
Limbic structures (mood and behavior)
You administer a drug to mice that inhibits serotonin synthesis. How will this affect the mice?
The mice will have insomnia.
What is an example of a noradrenergic pathway?
The pathway that arises from lateral reticular formation and innervates the hypothalamus and other limbic structures.
What is best-known group of cells in the noradrenergic pathways?
Locus ceruleus.
They project to every major region of the brain and spinal cord.
Where do most adrenergic fibers terminate?
On small blood vessels and capillaries in the brain.
They may help regulate blood flow in the brain.
Where are the majority of dopaminergic cells located?
In the substantia nigra.
What are some functions of the reticular formation?
Modulates sensation of pain
Modulates postural reflexes and muscle tone
Helps control breathing and heartbeat
Regulates level of brain arousal and consciousness
