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The heart is the driver of the circulatory system, pumping blood through rhythmic contraction and relaxation. The rate of blood flow out of the heart (often expressed in L/min) is known as the cardiac output (CO). Blood being pumped out of the heart first enters the aorta, the largest artery of the body.
An example is a system in which a protein P that is a product of gene G "positively regulates its own production by binding to a regulatory element of the gene coding for it," [14] and the protein gets used or lost at a rate that increases as its concentration increases. This feedback loop creates two possible states "on" and "off".
Regulatory enzymes are commonly the first enzyme in a multienzyme system: the product of the reaction catalyzed by the first enzyme is the substrate of the second enzyme, so the cell can control the amount of resulting product by regulating the activity of the first enzyme of the pathway.
Angiotensin-converting enzyme (EC 3.4.15.1), or ACE, is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstrictor angiotensin II .
All homeostatic control mechanisms have at least three interdependent components for the variable being regulated: a receptor, a control center, and an effector. [3] The receptor is the sensing component that monitors and responds to changes in the environment, either external or internal. Receptors include thermoreceptors and mechanoreceptors.
Cardiac markers are used for the diagnosis and risk stratification of patients with chest pain and suspected acute coronary syndrome and for management and prognosis in patients with diseases like acute heart failure. Most of the early markers identified were enzymes, and as a result, the term "cardiac enzymes" is sometimes used. However, not ...
The cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker via two sets of nerves: sympathetic fibres, part of the autonomic nervous system, to make heart rate faster. the vagus nerve, part of the parasympathetic branch of the autonomic nervous system, to lower heart rate.
It employs pacemaker cells that produce electrical impulses, known as cardiac action potentials, which control the rate of contraction of the cardiac muscle, that is, the heart rate. In most humans, these cells are concentrated in the sinoatrial (SA) node , the primary pacemaker, which regulates the heart’s sinus rhythm .