Medical research

Study finds calcium precisely directs blood flow in the brain

Unlike the rest of the body, there is not enough real estate in the brain for stored energy. Instead, the brain relies on the hundreds of miles of blood vessels within it to supply fresh energy via the blood. Yet, how the ...

Health

Red Cross warns of severe blood shortage

(HealthDay)—There's a severe blood shortage in the United States due to a recent surge in trauma cases, organ transplants and elective surgeries, the American Red Cross says.

Cardiology

Q and A: 21st century stroke prevention strategies

DEAR MAYO CLINIC: A family member had a stroke a month ago. I'm 45 years old, and I maintain a healthy lifestyle with regular exercise and a good diet. What steps can I take to make sure this doesn't happen to me?

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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