Diseases, Conditions, Syndromes

What is sepsis and how can it be treated?

Sepsis, colloquially known as blood poisoning, occurs as a result of an infection, usually from bacteria. Bacteria can enter the blood stream via an open wound, from another part of the body after a surgical procedure, or ...

Medical research

Crunching the numbers of cancer metastasis

In metastasis, cancer cells break away from the original tumor and take root in another region of the body by entering the blood stream. In order to spread, metastatic cells cross over the endothelium—a barrier of endothelial ...

Neuroscience

Sugar entering the brain during septic shock causes memory loss

The loss of memory and cognitive function known to afflict survivors of septic shock is the result of a sugar that is released into the blood stream and enters the brain during the life-threatening condition. This finding, ...

Medical research

Human protein produced in CHO-cells can save donor blood

Alpha-1-antitrypsin is a protein produced by the liver. The protein gets secreted to the blood stream, where it circulates the body to protect the lungs. However, some people are born with genetic disorders that hinders production ...

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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