Vascular headaches, a group that includes migraines, are thought to involve abnormal function of the brain's blood vessels or vascular system.
Vascular headaches are usually throbbing in character, and physical exertion increases the pain. Included under the classification of vascular headaches are migraine headaches, cluster headaches, and toxic headaches.
Veins as part of Vascular Headaches
Veins are larger than arteries; they have thinner walls with more muscle and less elastic. Blood flows from capillaries to venules and finally to veins, so the pressure drops as blood flows back to the heart. Valves are found throughout the venous system and prevent blood from flowing backwards. Because there is no direct pressure from the heartbeat in the venous system, it relies on the squeezing effect of surrounding muscle movement to make blood flow.
Capillaries as part of Vascular Headaches
Capillaries are tiny blood vessels with very thin walls, containing just a few muscle fibres. They form an immense network which would measure 60,000 miles if they were laid end to end. This makes them very important as a reservoir of blood. Their thin walls allow nutrients to pass through to surrounding tissues.