Cardiology

Hypertension poorly managed in low- and middle-income countries

Health systems in low- and middle-income countries (LMICs) are poorly prepared for the increasing number of people with high blood pressure, with more than two-thirds of people affected going without treatment, according ...

Medical research

Helping the body's ability to grow bone

For the first time, scientists have been able to study how well synthetic bone grafts stand up to the rigors and 'strains' of life, and how quickly they help bone re-grow and repair.

Medical research

Scaffold helps cells repair torn meniscus in lab tests

About a million times a year, Americans with a torn meniscus in their knee undergo surgery in hopes of a repair. Certain tears can't be fixed or won't heal well, and many patients later suffer osteoarthritis from the injury.

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Circulatory system

The circulatory system is an organ system that passes nutrients (such as amino acids and electrolytes), gases, hormones, blood cells, nitrogen waste products, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis. This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of the cardiovascular system, which distributes blood, and the lymphatic system, which distributes lymph. While humans, as well as other vertebrates, have a closed cardiovascular system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open cardiovascular system. The most primitive animal phyla lack circulatory system. The lymphatic system, on the other hand, is an open system.

The main components of the human circulatory system are the heart, the blood, and the blood vessels. The circulatory system includes: the pulmonary circulation, a "loop" through the lungs where blood is oxygenated; and the systemic circulation, a "loop" through the rest of the body to provide oxygenated blood. An average adult contains five to six quarts (roughly 4.7 to 5.7 liters) of blood, which consists of plasma, red blood cells, white blood cells, and platelets. Also, the digestive system works with the circulatory system to provide the nutrients the system needs to keep the heart pumping.

Two types of fluids move through the circulatory system: blood and lymph. The blood, heart, and blood vessels form the cardiovascular system. The lymph, lymph nodes, and lymph vessels form the lymphatic system. The cardiovascular system and the lymphatic system collectively make up the circulatory system.

This text uses material from Wikipedia, licensed under CC BY-SA