The circulatory system includes the lymphatic system, which circulates lymph. The passage of lymph for example takes much longer than that of blood. Blood is a fluid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. Lymph is essentially recycled excess blood plasma after it has been filtered from the interstitial fluid (between cells) and returned to the lymphatic system. The cardiovascular (from Latin words meaning “heart” and “vessel”) system comprises the blood, heart, and blood vessels. The lymph, lymph nodes, and lymph vessels form the lymphatic system, which returns filtered blood plasma from the interstitial fluid (between cells) as lymph. The function and health of the circulatory system and its parts are measured in a variety of manual and automated ways. These include simple methods such as those that are part of the cardiovascular examination, including the taking of a person’s pulse as an indicator of a person’s heart rate, the taking of blood pressure through a sphygmomanometer or the use of a stethoscope to listen to the heart for murmurs which may indicate problems with the heart’s valves. An electrocardiogram can also be used to evaluate the way in which electricity is conducted through the heart. Other more invasive means can also be used. A cannula or catheter inserted into an artery may be used to measure pulse pressure or pulmonary wedge pressures. Angiography, which involves injecting a dye into an artery to visualise an arterial tree, can be used in the heart (coronary angiography) or brain. At the same time as the arteries are visualised, blockages or narrowings may be fixed through the insertion of stents, and active bleeds may be managed by the insertion of coils. An MRI may be used to image arteries, called an MRI angiogram. For evaluation of the blood supply to the lungs a CT pulmonary angiogram may be used. Vascular ultrasonography include for example: Intravascular ultrasound Ultrasonography of deep venous thrombosis Ultrasonography of chronic venous insufficiency of the legs Current medical research the circulatory system Cardiac regeneration in 2017: Novel paradigms in the fight against heart failure Francisco Fernández-Avilés Important milestones in cardiac regenerative medicine that will define future research were reached in 2017: demonstration of adult cardiomyocyte renewal capacity, recognition of the importance of the extracellular matrix and the higher regenerative efficacy of repetitive dose protocols, and the publication of human data supporting paracrine effects of stem cell therapies and guidelines from TACTICS, the first international alliance on cardiac regenerative medicine References Lázár, E., Sadek, H. A. & Bergmann, O. Cardiomyocyte renewal in the human heart: insights from the fall-out. Eur. Heart J. 38, 2333–2342 (2017). Wang, W. E. et al. Dedifferentiation, proliferation, and redifferentiation of adult mammalian cardiomyocytes after ischemic injury. Circulation 136, 834–848 (2017). Bassat, E. et al. The extracellular matrix protein agrin promotes heart regeneration in mice. Nature 547, 179–184 (2017). Guo, Y. et al. Repeated doses of cardiac mesenchymal cells are therapeutically superior to a single dose in mice with old myocardial infarction. Basic Res. Cardiol. 112, 18 (2017). Stroke in 2017: Intensive and extensive — advances in stroke management The past year saw advances in endovascular treatment for acute stroke, speech therapy for aphasia after stroke, and cardiac disease management to prevent stroke. These treatments were characterized by more intensive or more extensive effects than standard care, necessitating thoughtful translation of the clinical trial findings into routine clinical practice.