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Types Of Blood Cells And Their Functions Pdf

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Blood cells are the cells which are produced during hematopoiesis and found mainly in the blood.

A blood cell , also called a hematopoietic cell , hemocyte , or hematocyte , is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells erythrocytes , white blood cells leukocytes , and platelets thrombocytes. Red blood cells or erythrocytes , primarily carry oxygen and collect carbon dioxide through the use of hemoglobin.

Blood cells and its types with functions

Blood is made of of several components, including red blood cells, white blood cells, platelets, and the plasma, which contains coagulation factors and serum. Blood helps maintain homeostasis by stabilizing pH, temperature, osmotic pressure, and by eliminating excess heat. Blood supports growth by distributing nutrients and hormones, and by removing waste.

These cells deliver oxygen to the cells and remove carbon dioxide. Blood plays a protective role by transporting clotting factors and platelets to prevent blood loss after injury.

These cells—including neutrophils, monocytes, lymphocytes, eosinophils, and basophils—are involved in the immune response. In birds and non-avian reptiles, a nucleus is still maintained in red blood cells. The principal job of this protein is to carry oxygen, but it also transports carbon dioxide as well.

Hemoglobin is packed into red blood cells at a rate of about million molecules of hemoglobin per cell. Each hemoglobin molecule binds four oxygen molecules so that each red blood cell carries one billion molecules of oxygen. In mammals, the lack of organelles in erythrocytes leaves more room for the hemoglobin molecules, and the lack of mitochondria also prevents use of the oxygen for metabolic respiration.

Only mammals have anucleated red blood cells, and some mammals camels, for instance even have nucleated red blood cells. The advantage of nucleated red blood cells is that these cells can undergo mitosis. Anucleated red blood cells metabolize anaerobically without oxygen , making use of a primitive metabolic pathway to produce ATP and increase the efficiency of oxygen transport. Not all organisms use hemoglobin as the method of oxygen transport.

Invertebrates that utilize hemolymph rather than blood use different pigments to bind to the oxygen. These pigments use copper or iron to the oxygen.

Invertebrates have a variety of other respiratory pigments. Chlorocruorin, a green-colored, iron-containing pigment is found in four families of polychaete tubeworms. Despite the name, hemerythrin does not contain a heme group and its oxygen-carrying capacity is poor compared to hemoglobin. In most vertebrates, a hemoglobin delivers oxygen to the body and removes some carbon dioxide. Hemoglobin is composed of four protein subunits, two alpha chains and two beta chains, and a heme group that has iron associated with it.

In most mollusks and some arthropods, b hemocyanin delivers oxygen. Unlike hemoglobin, hemolymph is not carried in blood cells, but floats free in the hemolymph. Copper instead of iron binds the oxygen, giving the hemolymph a blue-green color. In annelids, such as the earthworm, and some other invertebrates, c hemerythrin carries oxygen. Like hemoglobin, hemerythrin is carried in blood cells and has iron associated with it, but despite its name, hemerythrin does not contain heme.

The small size and large surface area of red blood cells allows for rapid diffusion of oxygen and carbon dioxide across the plasma membrane. In the lungs, carbon dioxide is released and oxygen is taken in by the blood. In the tissues, oxygen is released from the blood and carbon dioxide is bound for transport back to the lungs. Studies have found that hemoglobin also binds nitrous oxide NO. NO is a vasodilator that relaxes the blood vessels and capillaries and may help with gas exchange and the passage of red blood cells through narrow vessels.

Nitroglycerin, a heart medication for angina and heart attacks, is converted to NO to help relax the blood vessels and increase oxygen flow through the body. A characteristic of red blood cells is their glycolipid and glycoprotein coating; these are lipids and proteins that have carbohydrate molecules attached.

In humans, the surface glycoproteins and glycolipids on red blood cells vary between individuals, producing the different blood types, such as A, B, and O.

Red blood cells have an average life span of days, at which time they are broken down and recycled in the liver and spleen by phagocytic macrophages, a type of white blood cell.

The role of white blood cells is very different than that of red blood cells: they are primarily involved in the immune response to identify and target pathogens, such as invading bacteria, viruses, and other foreign organisms. White blood cells are formed continually; some only live for hours or days, but some live for years. The morphology of white blood cells differs significantly from red blood cells.

They have nuclei and do not contain hemoglobin. The different types of white blood cells are identified by their microscopic appearance after histologic staining, and each has a different specialized function. Granulocytes are typically first-responders during injury or infection.

Lymphocytes, including B and T cells, are responsible for adaptive immune response. Monocytes differentiate into macrophages and dendritic cells, which in turn respond to infection or injury.

Granulocytes contain granules in their cytoplasm; the agranulocytes are so named because of the lack of granules in their cytoplasm. Some leukocytes become macrophages that either stay at the same site or move through the blood stream and gather at sites of infection or inflammation where they are attracted by chemical signals from foreign particles and damaged cells.

Lymphocytes are the primary cells of the immune system and include B cells, T cells, and natural killer cells. B cells destroy bacteria and inactivate their toxins.

They also produce antibodies. T cells attack viruses, fungi, some bacteria, transplanted cells, and cancer cells. T cells attack viruses by releasing toxins that kill the viruses. Natural killer cells attack a variety of infectious microbes and certain tumor cells. One reason that HIV poses significant management challenges is because the virus directly targets T cells by gaining entry through a receptor.

After the HIV virus replicates, it is transmitted directly from the infected T cell to macrophages. The presence of HIV can remain unrecognized for an extensive period of time before full disease symptoms develop. Hemoglobin is responsible for distributing oxygen, and to a lesser extent, carbon dioxide, throughout the circulatory systems of humans, vertebrates, and many invertebrates. The blood is more than the proteins, though.

Blood is actually a term used to describe the liquid that moves through the vessels and includes plasma the liquid portion, which contains water, proteins, salts, lipids, and glucose and the cells red and white cells and cell fragments called platelets.

Blood plasma is actually the dominant component of blood and contains the water, proteins, electrolytes, lipids, and glucose. The cells are responsible for carrying the gases red cells and immune the response white. The platelets are responsible for blood clotting. Interstitial fluid that surrounds cells is separate from the blood, but in hemolymph, they are combined.

In humans, cellular components make up approximately 45 percent of the blood and the liquid plasma 55 percent. Blood must clot to heal wounds and prevent excess blood loss. Small cell fragments called platelets thrombocytes are attracted to the wound site where they adhere by extending many projections and releasing their contents. These contents activate other platelets and also interact with other coagulation factors, which convert fibrinogen, a water-soluble protein present in blood serum into fibrin a non-water soluble protein , causing the blood to clot.

Many of the clotting factors require vitamin K to work, and vitamin K deficiency can lead to problems with blood clotting. The plug or clot lasts for a number of days and stops the loss of blood.

For each megakaryocyte, — platelets are formed with , to , platelets present in each cubic millimeter of blood. They contain many small vesicles but do not contain a nucleus. The megakaryocyte breaks up into thousands of fragments that become platelets. The platelets collect at a wound site in conjunction with other clotting factors, such as fibrinogen, to form a fibrin clot that prevents blood loss and allows the wound to heal.

The liquid component of blood is called plasma, and it is separated by spinning or centrifuging the blood at high rotations rpm or higher. The blood cells and platelets are separated by centrifugal forces to the bottom of a specimen tube.

The plasma also contains the coagulation factors and antibodies. The plasma component of blood without the coagulation factors is called the serum. Serum is similar to interstitial fluid in which the correct composition of key ions acting as electrolytes is essential for normal functioning of muscles and nerves.

Other components in the serum include proteins that assist with maintaining pH and osmotic balance while giving viscosity to the blood. The serum also contains antibodies, specialized proteins that are important for defense against viruses and bacteria.

Lipids, including cholesterol, are also transported in the serum, along with various other substances including nutrients, hormones, metabolic waste, plus external substances, such as, drugs, viruses, and bacteria. Human serum albumin is the most abundant protein in human blood plasma and is synthesized in the liver.

Albumin, which constitutes about half of the blood serum protein, transports hormones and fatty acids, buffers pH, and maintains osmotic pressures.

Immunoglobin is a protein antibody produced in the mucosal lining and plays an important role in antibody mediated immunity. Red blood cells are coated in antigens made of glycolipids and glycoproteins. The composition of these molecules is determined by genetics, which have evolved over time. In humans, the different surface antigens are grouped into 24 different blood groups with more than different antigens on each red blood cell.

People with blood type A have antigen A, those with blood type B have antigen B, those with blood type AB have both antigens, and people with blood type O have neither antigen. Antibodies called agglutinougens are found in the blood plasma and react with the A or B antigens, if the two are mixed.

When type A and type B blood are combined, agglutination clumping of the blood occurs because of antibodies in the plasma that bind with the opposing antigen; this causes clots that coagulate in the kidney causing kidney failure.

Type O blood has neither A or B antigens, and therefore, type O blood can be given to all blood types. Type O negative blood is the universal donor. Type AB positive blood is the universal acceptor because it has both A and B antigen.

The Rh blood group was first discovered in Rhesus monkeys. The first exposure does not usually cause a reaction; however, at the second exposure, enough antibodies have built up in the blood to produce a reaction that causes agglutination and breakdown of red blood cells. An injection can prevent this reaction. Human red blood cells may have either type A or B glycoproteins on their surface, both glycoproteins combined AB , or neither O. The glycoproteins serve as antigens and can elicit an immune response in a person who receives a transfusion containing unfamiliar antigens.

Type O blood, which has no A or B antigens, does not elicit an immune response when injected into a person of any blood type. Thus, O is considered the universal donor.

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Red blood cell , also called erythrocyte , cellular component of blood , millions of which in the circulation of vertebrates give the blood its characteristic colour and carry oxygen from the lungs to the tissues. The mature human red blood cell is small, round, and biconcave; it appears dumbbell-shaped in profile. The cell is flexible and assumes a bell shape as it passes through extremely small blood vessels. It is covered with a membrane composed of lipids and proteins, lacks a nucleus , and contains hemoglobin —a red iron-rich protein that binds oxygen. The function of the red cell and its hemoglobin is to carry oxygen from the lungs or gills to all the body tissues and to carry carbon dioxide , a waste product of metabolism, to the lungs, where it is excreted. In invertebrates, oxygen-carrying pigment is carried free in the plasma; its concentration in red cells in vertebrates, so that oxygen and carbon dioxide are exchanged as gases, is more efficient and represents an important evolutionary development.

Red blood cells, or erythrocytes, are one of the components of blood. The others are plasma, platelets and white blood cells. They are continuously produced in our bone marrow. Red blood cells carry oxygen from our lungs to the rest of our bodies. Then they make the return trip, taking carbon dioxide back to our lungs to be exhaled. A low red blood cell count, known as anemia, can cause fatigue, shortness of breath, dizziness and other symptoms.

Stem cells are multipotential cells (capable of developing into different types of blood cells). Some stem cells enter the blood and circulate. Red blood cells carry​.

Different Types of Blood Cells and Their Roles in the Human Body

White blood cells WBCs are a part of the immune system that helps fight infection and defend the body against other foreign materials. Different types of white blood cells are involved in recognizing intruders, killing harmful bacteria, and creating antibodies to protect your body against future exposure to some bacteria and viruses. There are several different types of white blood cells. They are also known as leukocytes. Neutrophils make up roughly half of the white blood cell population.

What to know about white blood cells

The heart pumps blood through the arteries, capillaries and veins to provide oxygen and nutrients to every cell of the body. The blood also carries away waste products. The adult human body contains approximately 5 liters of blood.

Red blood cell

Blood is made of of several components, including red blood cells, white blood cells, platelets, and the plasma, which contains coagulation factors and serum. Blood helps maintain homeostasis by stabilizing pH, temperature, osmotic pressure, and by eliminating excess heat. Blood supports growth by distributing nutrients and hormones, and by removing waste. These cells deliver oxygen to the cells and remove carbon dioxide.

The liquid component of the blood in which the following blood cells are suspended:. Red blood cells erythrocytes. These carry oxygen from the lungs to the rest of the body. White blood cells leukocytes. These help fight infections and aid in the immune process.

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Types and Function of White Blood Cells (WBCs)

 Какое отношение это имеет к директорскому кабинету.


Melanie B. 17.12.2020 at 04:39

White blood cells circulate around the blood and help the immune system fight off infections.

Aceline B. 17.12.2020 at 10:48

Blood , fluid that transports oxygen and nutrients to the cells and carries away carbon dioxide and other waste products.