Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.
In vertebrates, it is composed of blood cells suspended in a liquid called blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume),[1] and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves.
Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes andplatelets.
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 thisrespiratory gas and greatly increasing its solubility in blood.
In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma as bicarbonate ion.
Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes andplatelets.
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 thisrespiratory 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 ascrustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin.
Insects and some mollusks 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.
Insects and some mollusks 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 withlungs, 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 theAncient Greek word αἷμα (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 offibrinogen.
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 offibrinogen.
The functions of the blood are:
1.to transport oxygen away from the lungs and around the body; and CO2 from the body cells to the lungs.
2.to transport nutrients such as glucose and amino acids from the digestive system to the cells in our bodies.
3.to take waste products such as lactic acid away from the muscles when it's produced by anaerobic respiration; and urea from the liver to the kidneys and bladder.
4.By maintaining a good circulation, the bloodflow keeps your core body temperature at a steady 37oC.
5.White blood cells help kill pathogens and microbes that stray into the body.
6.Substances like platelets and fibrin in the blood help to clot wounds.
Constituents of human blood
Blood accounts for 8% of the human body weight,with an average density of approximately 1060 kg/m3, very close to pure water's density of 1000 kg/m3.The average adult has a blood volume of roughly 5 liters (1.3 gal), composed of plasma and several kinds of cells (occasionally called corpuscles); these formed elements of the blood are erythrocytes (red blood cells, RBCs), leukocytes (white blood cells), and thrombocytes (platelets). By volume, the red blood cells constitute about 45% of whole blood, the plasma about 54.3%, and white cells about 0.7%.
Whole blood (plasma and cells) exhibits non-Newtonian fluid dynamics; its flow properties are adapted to flow effectively through tiny capillary blood vessels with less resistance than plasma by itself.
In addition, if all human hemoglobin were free in the plasma rather than being contained in RBCs, the circulatory fluid would be too viscous for the cardiovascular system to function effectively.
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In addition, if all human hemoglobin were free in the plasma rather than being contained in RBCs, the circulatory fluid would be too viscous for the cardiovascular system to function effectively.
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