Blood pressure is an important medical topic often found in discussions relating to heart disease, stroke, and general dietary concerns, such as a high salt diet. But beyond ones particular health habits, the body has its own internal systems, which automatically regulate blood pressure. Ultimately, these systems like most everything else in the body, is inherently tied to brain function.
The area of the brain responsible for regulating blood pressure is the medulla oblongata. This is part of the brain stem and lies bellow the mid-brain and the pons. Evolutionarily speaking, it is the oldest area of the brain, sharing its basic structure with more primitive forms of life, such as reptiles. It is directly connected to the spinal cord and thus acts as the transit point of all information going to and from the brain. Given that, its function is the regulation of the most basic aspects of life, breathing, heart rate, and blood pressure.
How the medulla regulates blood pressure
The medulla oblongata regulates blood pressure in the body through the use of what are called baroreceptors. These receptors detect changes in pressure throughout the circulatory system and then translates those changes into electro-chemical signals snet to the medulla. They do this by automatically responding to the stretching or contraction that occurs to the arterial wall.
Changing the heart rate
Due to the fact that the organs of the body require proper blood flow within a relatively narrow optimum blood pressure, when the medulla receives these signals, it either increases or decreases the heart rate through the sympathetic or parasympathetic nervous system. The sympathetic nervous system generally regulates the bodies automatic function during times of stress, and the parasympathetic does so in regular functioning.
Restricting or expanding blood flow
In addition to changing the rate at which the heart pumps blood, the medulla can stimulate the contraction or expansion of blood vessels in order to restrict or increase blood flow. The combination of these changes stimulated by the medulla is what ultimately controls blood pressure in the body.
Outside factors affecting blood pressure
There is a negative feedback loop, which is constantly being influenced by the internal and external factors affecting the body. For example, a person experiencing stress caused by life threatening situations will have an increase in adrenaline in their blood, this can also stimulate changes in heart rate and blood flow, thus affecting blood pressure as well. This is why people who have high blood pressure are generally told to avoid stressful or dangerous situations.
Currently, there are efforts underway to use electronic implants in order to help the brain regulate blood pressure better in those patients which are at high risk for stroke and other high blood pressure related diseases.