Health

Engineered mattress tricks your body to fall asleep faster

When people feel sleepy or alert, that sensation is controlled in part by the ebb and flow of a 24-hour rhythm of their body temperature. Bioengineers at The University of Texas at Austin have developed a unique mattress ...

Medical research

Loss of male sex chromosome leads to earlier death for men

The loss of the male sex chromosome as many men age causes the heart muscle to scar and can lead to deadly heart failure, new research from the University of Virginia School of Medicine shows. The finding may help explain ...

Health

Ukraine war and refugee health

For health care providers who may be caring for Ukrainians displaced by the war, a new analysis published in CMAJ (Canadian Medical Association Journal) provides an overview of health and clinical considerations in this population. ...

Health

Study finds low vitamin D levels in young people of color

Results from a University of Houston College of Nursing study indicate that 61% of otherwise healthy Black and Hispanic adolescents have low vitamin D levels, that drop even lower with age. The research fills a knowledge ...

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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