Typically veins are generally wider than arteries, and therefore the pressure is lower. Capillaries are tiny vessels, so repsent high resistance to the incoming blood, so the rate of blood flow through will be quite low. All blood from the artery eventually passes through capillaries and into the vein.
Graves' disease. Graves' disease is the most common cause of overactive thyroid. It can run in families and can occur at any age, although it is most common in women aged 20-40 years old. You are more likely to develop Graves' disease if you smoke. Graves' disease is an autoimmune condition.
Worldwide, a lack of dietary iodine is a common cause of an underactive thyroid, because the body needs iodine to make thyroxine. However, iodine deficiency is uncommon in the UK. Babies are sometimes born with an underactive thyroid because the thyroid gland doesn't develop properly in the womb.his damages the thyroid, which means it's not able to make enough of the hormone thyroxine, leading to the symptoms of an underactive thyroid. A condition called Hashimoto's disease is the most common type of autoimmune reaction that causes an underactive thyroid.