Answer
Generally, parasympathetic activation is antagonistic to sympathetic stimulation; that is, it produces opposite effects:
1. Parasympathetic stimulation constricts rather than dilates eye pupils
2. Parasympathetic impulses lower heart rate
3. Parasympathetic stimulation constricts bronchioles of the lungs
4. Parasympathetic stimulation increases uptake of glucose by the liver
5.The effect of parasympathetic impulses on the salivary glands is to promote the secretion of a
watery saliva rather than the saliva of thick viscous consistency produced by sympathetic stimulation
Work Step by Step
Generally parasympathetic activation is antagonistic to sympathetic stimulation , that is, it produces opposite effects:
Instead of dilating the pupil as sympathetic stimulation does, parasympathetic stimulation constricts pupils. Other antagonsic effects of parasympathetic action to sympathetic activation include the following:
A. Simulation of increased GI glandular activity.
B. Decrease of heart rate
c. Constriction of bronchioles of the lungs
d. Increase of uptake of glucose by the liver
It should be noted that mainly because of the absence of parasympathetic innervation some aogans that respond positively to sympathetic stimuli are not affected the prasympathetic system activity. Some examples are the following:
---Parasympathetic system has no effect on sweat glands
--- No effect on adrenal medulla
---No effect on renin secretion by kidneys
---No effect on metabolic rate (lipolysis)
Effect on blood vessels is minimal
Note : parasympathetic effects on GI viscera are significant: It increases secretion of GI glands;
increases GI motility and it relaxes GI sphincters
