A headache may be sharp, throbbing, constant, mild or intense. A headache could also be described as a dull ache. Since the brain itself has no nerves, it cannot experience pain. However, pain receptors are located in the tissues and structures that surround the brain. Those areas include the periosteum that surrounds bones, the muscles that encase the skull, the sinuses, the eyes and ears, as well as the meninges that cover the surface of the brain. Additionally, the spinal cord, the arteries, the veins, and the nerves can become inflamed or irritated to cause a headache.
Headaches & Migraines
Migraines are painful headaches often accompanied by nausea, vomiting, and sensitivity to light. The exact causes of migraine headaches are unknown but known triggers include fatigue, loud noise, bright lights and weather changes.
For many years, scientists believed that migraines resulted from expanding and constricting blood vessels on the brain's surface. However, it is now believed that migraines are caused by inherited abnormalities in different areas of the brain. People with migraines may also inherit the tendency to get migraines.
A migraine headache begins when irriatated nerve cells send messages to the blood vessels, causing them to clamp down or constrict.
The vessels then dilate, releasing serotonin, prostaglandins and other inflammatory substances.