Medical research

Nanotubes in the eye that help us see

A new mechanism of blood redistribution that is essential for the proper functioning of the adult retina has just been discovered in vivo by researchers at the University of Montreal Hospital Research Centre (CRCHUM).

Diseases, Conditions, Syndromes

Study reveals immune-system paralysis in severe COVID-19 cases

A Stanford study shows that in severely ill COVID-19 patients, "first-responder" immune cells, which should react immediately to signs of viruses or bacteria in the body, instead respond sluggishly.

Medical research

Using models, 3-D printing to study common heart defect

One of the most common congenital heart defects, coarctation of the aorta (CoA) is a narrowing of the main artery transporting blood from the heart to the rest of the body. It affects more than 1,600 newborns each year in ...

Diseases, Conditions, Syndromes

Malaria discovery could expedite antiviral treatment for COVID-19

The study, conducted by an international team and led by RMIT University's Professor Christian Doerig, outlines a strategy that could save years of drug discovery research and millions of dollars in drug development by repurposing ...

Diseases, Conditions, Syndromes

Oxytocin can help prevent osteoporosis

Oxytocin, produced by the hypothalamus and sometimes known as the "love hormone" for its involvement in pair bonding and orgasm, can be a strong ally in the control and prevention of osteoporosis, according to a study by ...

Medical research

New treatment targets found for blinding retinal disease

When the eye isn't getting enough oxygen in the face of common conditions like premature birth or diabetes, it sets in motion a state of frenzied energy production that can ultimately result in blindness, and now scientists ...

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Blood

Blood is a specialized bodily fluid that delivers necessary substances to the body's cells — such as nutrients and oxygen — and transports waste products away from those same cells.

In vertebrates, it is composed of blood cells suspended in a liquid called blood plasma. Plasma, which comprises 55% of blood fluid, is mostly water (90% by volume), and contains dissolved proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), platelets and blood cells themselves. The blood cells present in blood are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes and platelets. The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates transportation of oxygen by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma as bicarbonate ion.

Vertebrate blood is bright-red when its hemoglobin is oxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin. Insects and some molluscs use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suffice for supplying oxygen.

Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system.

Blood is circulated around the body through blood vessels by the pumping action of the heart. In animals having lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled.

Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Ancient Greek word αἶμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue, given its origin in the bones and the presence of potential molecular fibers in the form of fibrinogen.

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