Gene found that causes eyes to wither in cavefish

Mexican cavefish spend their entire lives in the dark. With no need for vision, many of them lost functional eyes. In more than 30 varieties of Mexican cavefish, the eyes stop developing as embryos grow into larvae. Although ...

Probing the secret forces of pericytes

Leiden researchers found a way to measure the tiny forces exerted by pericytes, one of the most elusive, hard to research cell types, which occur in tiny blood vessels. Building on this fundamental science, researchers may ...

Extraction of skin interstitial fluid using microneedle patches

Interstitial fluid is a major component of the liquid environment in the body and fills the spaces between the body's cells. In contrast, blood circulates only within the circulatory vessels of the body and is composed of ...

Scientists find optimal age of stem cells

Biophysicists from the Moscow Institute of Physics and Technology and Vladimirsky Moscow Regional Clinical Research Institute have determined the optimal age of reprogrammed stem cells suitable for restoring heart tissue. ...

Increased usability and precision in vascular imaging

Researchers at the University of Zurich have developed a new X-ray contrast agent. The contrast agent is easier to use and distributes into all blood vessels more reliably, increasing the precision of vascular imaging. This ...

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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