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.
Heart passages open vertically (atrium and ventricle) and the heart is divided into side-by-side pumps serving two blood circuits: 1  Pulmonary circuit - receives blood returning to the heart from the body and sends it through the lungs for oxygenation.  Systemic circuit - supplies the entire body with oxygenated blood.