Chapter 58 Flashcards
(41 cards)
What are the two types of cerebellar excitatory signals?
- Short acting excitatory signal caused by acetylcholine release from the brainstem reticular area
- Longer acting excitatory signals from the reticular excitatory area which project through the inralaminal nuclei of that thalamus and excite the cortex
What happens when the excitatory area in the pons around the level of the 5th CN is cut? What is the name of this strucutre?
- coma results
- reticular excitatory area
What is the general idea of the positive feedback loop between the excitatory area and the cortex?
the exitatory area causes excitation of the cortex, then the cortex returns an excitory signal to the bulboreticular area. This causes a positive feedback allowing for an awake state
Which brain structure acts as the relay and distribution center for activity in the cortex?
thalamus
What else does the thalamus do for the gigantocellular input as it passes to the cortex?
modulates it
What is the main purpose of the reticuloinhibitory area? What is its principle neurotransmitter?
decrease activity of the upper cortex
-serotonin
Where is the locus ceruleus?
Ponto-mesencephalon junction
What NT is released from the locus ceruleus? What is the result?
- Norepiepherine
- Generally excites the brain but does inhibit some areas
Where is the substantia nigra? What NT does it relase?
- midbrain
- dopamine
What is the action of dopamine in the brain?
-inhibitory NT on the basal nuclei
Where are the raphe nuclei and what NT do they secrete?
- midline pons
- serotonin
Where do fibers from the raphe nuclei project and what is the function of the serotonin released there?
- projecto to the diencephalon and cortex as well as the spinal cord
- in the upper levels it is inhibitory and is essential in sleep
- in the cord is supresses pain
Where are the gigantocellular neurons and what NT do they release? What is its impact?
- reticular area of the pons and mesencephalon
- Acetycholine
- excitatory function in bothe the cortex and the spinal cord (causes wakefulness)
Neurohormonal systems in the human brain (image)
What is the general role of the limbic system?
- modulate emotions and behavior
- also internal conditions like body temp, fluid osmolality, and drive to eat and drink
What are the three directions of pathways out of the hypothalamus?
- downward and outward
- upward
- into the hypothalamic infundibulum
What is the function of the hypothalamic pathway travelling downward and outward?
Travels to the brainstem (mainly to the reticular areas, mesencephalon, pons an medualla) and onward into the peripheral nerves of the ANS.
Where do the upward tracts from the hypothalamus continue on to?
-higher areas of the diencephalon and cerebrum
What is the function of the tracts that run from the hypothalamus through the infundibular stalk?
-function to contol or partially control the secretory functions of both the anterior and posterior pituitary
Where does stimulation in the hypothalamus result in an increase in blooooode pressure?
-posterior and lateral hypothalamus (increase in arterial pressure and heart rate)
Where does stimulation in the hypothalamus result in a decrease in blood pressure?
-in the preoptic area
How does the hypothalamus contribute to the regulation of body temperature?
-An increase in temperature of blood through the anterior portion of the hypothalamus results in an increase in activity of temperature sensitive neurons, while a decrease does the opposite.
In what two ways does the hypothalamus regulate body water?
- by creating the sensation of thirst
- by controlling the excretion of water into the urine (vasopressin or ADH)
Which nuclei is involved in the control of water excretion by the kidneys?
-supraoptic nuclei
