These agents all exert their effect by being converted to nitric oxide in the body by mitochondrial aldehyde dehydrogenase (ALDH2), and nitric oxide is a potent natural vasodilator. In medicine, nitroglycerin is probably most commonly prescribed for angina pectoris, a painful symptom of ischemic heart disease caused by inadequate flow of blood and oxygen to the heart and as a potent antihypertensive agent. Nitroglycerin corrects the imbalance between the flow of oxygen and blood to the heart and the heart’s energy demand. There are plenty of formulations on the market at different doses. At low doses, nitroglycerin dilates veins more than arteries, thereby reducing preload (volume of blood in the heart after filling); this is thought to be its primary mechanism of action. By decreasing preload, the heart has less blood to pump, which decreases oxygen requirement since the heart does not have to work as hard. Additionally, having a smaller preload reduces the ventricular transmural pressure (pressure exerted on the walls of the heart), which decreases the compression of heart arteries to allow more blood to flow through the heart. At higher doses, it also dilates arteries, thereby reducing afterload (decreasing the pressure against which the heart must pump). An improved ratio of myocardial oxygen demand to supply leads to the following therapeutic effects during episodes of angina pectoris: subsiding of chest pain, decrease of blood pressure, increase of heart rate, and orthostatic hypotension.
Acephaly (in Greek: a = without / képhalê = head) is a term used to define:

In medicine:
in forensic medicine: a decapitated corpse whose head has not been found
Twin reversed arterial perfusion
an animal without a head. For example:
Great scallop
Maggot, the larva of the fly
a relatively complete sculpture, the head of which has not been found. For example:
Winged Victory of Samothrace
Venus of Arles
Commons:Category:Headless statues