Diseases, Conditions, Syndromes

New study may help explain low oxygen levels in COVID-19 patients

A new study published in the journal Stem Cell Reports by University of Alberta researchers is shedding light on why many COVID-19 patients, even those not in hospital, are suffering from hypoxia—a potentially dangerous ...

Oncology & Cancer

As seasons change, so should diet for breast cancer survivors

Just as the four seasons bring changes in nature, they also impact how our bodies assimilate and metabolize food. Research indicates winter brings higher metabolic rates compared with summer, and so it calls for energy efficient ...

Psychology & Psychiatry

COVID affects everything—even your sex life

I had a nasty case of COVID-19 several months ago. It's taken a while, but I'm fully recovered—except for one thing: I've been having trouble getting and keeping an erection. I know that most men have erection troubles ...

Psychology & Psychiatry

Cocoa flavanols boost brain oxygenation, cognition in healthy adults

The brains of healthy adults recovered faster from a mild vascular challenge and performed better on complex tests if the participants consumed cocoa flavanols beforehand, researchers report in the journal Scientific Reports. ...

Diseases, Conditions, Syndromes

Malaria parasites hide out in humans when it's not mosquito season

Malaria parasites survive the mosquito-free dry season by waiting silently in humans for the return of the rainy season that brings back with it mosquitoes. New research, by an international team including Penn State scientists, ...

page 1 from 17

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