More early signs of pregnancy include an aching head, a result of changes in hormones. Just in case you are indeed pregnant, take pg-safe acetaminophen instead of ibuprofen to deal with the pain.
Organs Without Dual Innervation. Although most organs are innervated by both sympathetic and parasympathetic nerves, some-including the adrenal medulla, arrector pili muscles, sweat glands, and most blood vessels-receive only sympathetic innervation.
In vessels that contain more than one layer of smooth muscle, only the outermost cells receive sympathetic innervation. Smooth muscle cells of the inner portions of the medial layer contract due to the diffusion of norepinephrine and cell-to-cell communication mediated by gap junctions.ympathetic Neural Control of Blood Vessels. Postganglionic sympathetic nerves are localized to the adventitial-medial border of most arteries, arterioles, and veins throughout the body. Venules and capillaries, which lack smooth muscle, are not directly innervated by sympathetic nerves.