The medulla oblongata and pons are the circulatory centers of the brain and constantly receive information on blood pressure and gas composition. From here, actions to regulate the circulation are initiated if necessary, which is known as central circulatory regulation. In cardiovascular disease, the system is disrupted.
What is central circulatory regulation?
The circulatory system corresponds to a flow system and, at the same time, to the path that blood travels from the heart in the cardiovascular system. The blood circulation corresponds to a flow system and, at the same time, to the path that the blood travels from the heart in the cardiovascular system. The flow system of the blood circulation thus consists of the heart on the one hand and the blood vessels on the other. Blood vessels that supply the heart are called veins. Outgoing vessels are called arteries. Blood vessels are more branched and smaller the farther they are from the heart. Regardless of environmental and load-dependent conditions, the body must maintain blood supply to individual tissues and organs at all times. Vital oxygen reaches the tissues with the blood. Cardiac actions and blood pressure are permanently regulated so that each organ of the body is supplied with a minimum amount of oxygen and blood. This regulation is ensured by various mechanisms. One of them is central circulatory regulation. This circulatory regulation occurs in medulla oblongata and pons. The circulatory system has various sensors that permanently transmit information about the current circulatory situation to these areas of the brain. In these areas, the information is evaluated and, if necessary, regulatory actions take place.
Function and task
The wall of the aorta and the walls of the internal carotid artery are equipped with mechanoreceptors that detect stretch and pressure stimuli. These receptors are also located in the carotid sinus, vena cava, and atria. The sensory cells are baroreceptors. Arterial baroreceptors are high pressure baroreceptors. Venous baroreceptors are located in the low-pressure system of the vena cavae. By registering strain, they continuously detect blood pressure. They convert this information into action potentials, translating it into a language that the central nervous system can process. In addition to blood pressure information from the baroreceptors, detected gas partial pressures or pH also play a role in central circulatory regulation. This information is also determined by receptors. Sensory cells with this task are called chemoreceptors and are mainly located in the paraganglia of the carotid, aorta and pulmonary artery. Together with the information from the baroreceptors, that from the chemoreceptors thus also reaches the circulatory center of the afterbrain (medulla oblongata). The information from the chemoreceptors provides the medulla oblongata with information about the current gas composition and oxygen content of the blood. If the oxygen content falls below the physiologically intended level, the afterbrain initiates counter-regulatory measures, mainly related to respiration. Regulatory countermeasures based on blood pressure information take place in the brain exclusively after acute changes in blood pressure. Such acute changes are part of everyday life and await people, for example, when lying down or standing up from a lying position. In these situations, the blood rapidly changes position due to gravity and is in danger of becoming engorged. Accordingly, central circulatory regulation does not refer to slow changes in blood pressure that are kept constant after they occur. For example, if blood pressure runs permanently at a higher or lower level, the organism adapts to the new level. After the adjustment, the new blood pressure is held constant.
Diseases and ailments
Diseases with disorders of central circulatory regulation usually involve the heart or blood vessels. In the circulatory system, the heart is the motor and keeps the blood constantly moving by pumping. Thus, a disturbed heart function can not only cause circulatory problems, but also lead to organic damage. When circulatory regulation is disturbed by heart disease, too little oxygen or blood may reach the tissues of the organs. This relationship may be responsible for heart-related organ damage.In all cardiovascular diseases, complaints with the central circulatory regulation can occur. These diseases are a large group of diseases and include, for example, angina pectoris, arteriosclerosis, chronic high blood pressure, diabetes, cardiac arrhythmias or strokes. Most cardiovascular diseases are promoted by stress, medication, smoking, lack of exercise and poor diet. Arteriosclerosis, in particular, has become a relatively widespread disease. The disease corresponds to the deposition of fats, connective tissue or calcium within the blood vessels. The exact causes of arteriosclerosis are not conclusively understood. A starting point for the disease seems to be dysfunctions or damages of the endothelium. As a result of the damage, LDL molecules reach the subendothelial layers in the tunica intima. Thus, oxidative processes are favored, causing inflammatory reactions and plaque formation. Strokes, heart attacks, and renal insufficiency can be secondary diseases. Arteriosclerosis is often asymptomatic in the first years. However, the plaques gradually narrow the blood vessels and the vessel lumen decreases. If the narrowing is severe, there is a risk of occlusion, which can cause functional impairment of the circulatory system or even a heart attack. In addition, the vessel walls may tear. The formation of thrombi is the result. In individuals over the age of 80, the condition is usually an age-related phenomenon. Family history has also been documented for the development of the disease. Other risk factors include lack of exercise, pre-existing conditions such as obesity, and habits such as smoking. Equally well, hypercholesterolemia, diabetes mellitus, or hypertension (high blood pressure) can lead to calcification of the vessels, causing the secondary diseases mentioned, in addition to problems with central circulation regulation.
