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A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a
cell Cell most often refers to: * Cell (biology) The cell (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around ...
produced through
hematopoiesis Haematopoiesis (, from Ancient Greek, Greek , 'blood' and 'to make'; also hematopoiesis in American English; sometimes also h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from hematopoiet ...
and found mainly in the
blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isochoric flow) refers t ...

blood
. Major types of blood cells include
red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek language, Greek ''erythros'' for "red" and ''k ...

red blood cell
s (erythrocytes),
white blood cell White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system The immune system is a network of biological processes that protects an organism In biology, an organism (from Ancient Greek, Greek: ...
s (leukocytes), and
platelet Platelets, also called thrombocytes (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. ...

platelet
s (thrombocytes). Together, these three kinds of blood cells add up to a total 45% of the blood tissue by volume, with the remaining 55% of the volume composed of
plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral) or heliotrope, a mineral aggregate * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood plasma ...
, the liquid component of blood.


Red blood cells

Red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek language, Greek ''erythros'' for "red" and ''k ...

Red blood cell
s or ''erythrocytes'', primarily carry
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
and collect
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

carbon dioxide
through the use of
hemoglobin Hemoglobin or haemoglobin (spelling differences Despite the various English dialects Dialect The term dialect (from Latin , , from the Ancient Greek word , , "discourse", from , , "through" and , , "I speak") is used in two distinct wa ...

hemoglobin
. Hemoglobin is an
iron Iron () is a chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behav ...

iron
-containing protein that gives red blood cells their color and facilitates transportation of
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
from the
lung The lungs are the primary organs An organ is a group of tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ's tissues can be broadly categorized as parenchyma ...

lung
s to tissues and
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

carbon dioxide
from tissues to the lungs to be exhaled. Red blood cells are the most abundant cell in the blood, accounting for about 40-45% of its volume. Red blood cells are circular, biconcave, disk-shaped and deformable to allow them to squeeze through narrow capillaries. They do not have a nucleus. Red blood cells are much smaller than most other human cells. RBCs are formed in the red bone marrow from
hematopoietic stem cells Hematopoietic stem cells (HSCs) are the stem cell In multicellular organisms Multicellular organisms are organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contigu ...
in a process known as
erythropoiesis Erythropoiesis (from Greek 'erythro' meaning "red" and 'poiesis' "to make") is the process which produces red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus ...
. In adults, about 2.4 million RBCs are produced each second. The normal RBCs count is 4.5 to 5 millions per cu.mm. RBCs have a lifespan of approximately 100-120 days. After they have completed their lifespan, they are removed from the bloodstream by the
spleen The spleen is an organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ's ...

spleen
. Mature red blood cells are unique among cells in the human body in that they lack a nucleus (although
erythroblasts A nucleated red blood cell (NRBC), also known by #Nomenclature, several other names, is a red blood cell that contains a cell nucleus. Almost all vertebrate organisms have hemoglobin-containing cells in their blood, and with the exception of mamma ...
do have a nucleus). The condition of having too few red blood cells is known as
anemia Anemia (American and British English spelling differences#ae and oe, also spelled anaemia) is a decrease in the total amount of red blood cells (RBCs) or hemoglobin in the blood, or a lowered ability of the blood to carry oxygen. When anemia c ...

anemia
, while having too many is
polycythemia Polycythemia (also known as polycythaemia or polyglobulia) is a disease state in which the hematocrit The hematocrit () (Ht or HCT), also known by several other names, is the volume percentage (vol%) of red blood cell Red blood cells (RBCs), a ...
. Erythrocyte sedimentation rate (ESR) is the rate at which RBCs sink to the bottom (when placed in a vertical column after adding an anticoagulant). Normal values of ESR are: • 3 to 5 mm per hour in males. • 4 to 7 mm per hour in females.


White blood cells

White blood cell White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system The immune system is a network of biological processes that protects an organism In biology, an organism (from Ancient Greek, Greek: ...
s or ''leukocytes'', are cells of the
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as Tumor immunology, cancer cells and objects such ...
involved in defending the body against both
infectious disease An infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host A host is a person responsible for guests at an event or for providing hospitality during it. Host may ...
and foreign materials. They are produced and derived from multipotent cells in the
bone marrow Bone marrow is a semi-solid tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North America * ''Triphos ...
known as a
hematopoietic stem cell Hematopoietic stem cells (HSCs) are the stem cell In multicellular organisms Multicellular organisms are organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguo ...

hematopoietic stem cell
s. Leukocytes are found throughout the body, including the blood and
lymphatic system The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the circulatory system and the immune system. It is made up of a large network of lymph, lymphatic vessels, lymph nodes, lymphatic or lymphoid organs, an ...

lymphatic system
. There are a variety of types of white bloods cells that serve specific roles in the human immune system. WBCs constitute approximately 1% of the blood volume. White blood cells are divided into
granulocyte Granulocytes are cells in the innate immune system The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutiona ...
s and
agranulocyte Agranulocytes or nongranulocytes, also mononuclear leukocytes, are one of the two types of white blood cells, also known as leukocytes. The other type of white blood cells are known as granulocytes. Agranular cells are noted by the absence of Gra ...
s, distinguished by the presence or absence of granules in the cytoplasm. Granulocytes include
basophils Basophils are a type of white blood cell White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system The immune system is a network of biological processes that protects an organism In biolo ...
,
eosinophils Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cell White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system The immune system is a network ...
,
neutrophils Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...

neutrophils
, and
mast cells #REDIRECT Mast cell#REDIRECT Mast cell A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived fr ...

mast cells
. Agranulocytes include
lymphocytes A lymphocyte is a type of white blood cell in the immune system of gnathostomata, jawed vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated immunity, cell-mediated, cytotoxicity, cytotoxic innate immune system, i ...

lymphocytes
and
monocytes Monocytes are a type of ''leukocyte'', or white blood cell White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system The immune system is a network of biological processes that protects an organi ...

monocytes
. The condition of having too few white blood cells is
leukopenia Leukopenia () is a decrease in the number of leukocytes. Found in the blood, they are the white blood cells, and are the body's primary defense against an infection. Thus the condition of leukopenia places individuals at increased risk of infection ...
, while having too many is
leukocytosis Leukocytosis is a condition in which the white cell (leukocyte White blood cells, also called leukocytes or leucocytes, are the of the that are involved in protecting the body against both and foreign invaders. All white blood cells are p ...
. There are individual terms for the lack or overabundance of specific types of white blood cells. The number of white blood cells in circulation is commonly increased in the incidence of
infection An infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host A host is a person responsible for guests at an event or for providing hospitality during it. Host may ...

infection
. Many
hematological cancer Tumors of the hematopoietic and lymphoid tissues (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United ...
s are based on the inappropriate production of white blood cells.


Platelets

Platelet Platelets, also called thrombocytes (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. ...

Platelet
s, or ''thrombocytes'', are very small, irregularly shaped clear cell fragments, 2–3 µm in diameter, which derive from fragmentation of
megakaryocytes A megakaryocyte (''mega- Mega is a unit prefixA unit prefix is a specifier or mnemonic that is prepended to units of measurement to indicate multiples or fractions of the units. Units of various order of magnitude, sizes are commonly formed by th ...
. The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors. They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots. Platelets release thread-like fibers to form these clots. The normal range (99% of population analyzed) for platelets is 150,000 to 450,000 per cubic millimeter. If the number of platelets is too low, excessive bleeding can occur. However, if the number of platelets is too high, blood clots can form thrombosis, which may obstruct blood vessels and result in such events as a
stroke A stroke is a medical condition A disease is a particular abnormal condition that negatively affects the structure or function (biology), function of all or part of an organism, and that is not due to any immediate external injury. Di ...

stroke
,
myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynamics, dynamics of blood flow. The circulatory sy ...

myocardial infarction
,
pulmonary embolism Pulmonary embolism (PE) is a blockage of an pulmonary artery, artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include dyspnea, shortness of breath, chest pain p ...

pulmonary embolism
, or blockage of blood vessels to other parts of the body, such as the extremities of the arms or legs. An abnormality or disease of the platelets is called a thrombocytopathy, which can be either a low number of platelets (
thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care units, intensive care patients and is seen in 20% of med ...

thrombocytopenia
), a decrease in function of platelets (thrombasthenia), or an increase in the number of platelets (thrombocytosis). There are disorders that reduce the number of platelets, such as
heparin-induced thrombocytopenia Heparin-induced thrombocytopenia (HIT) is the development of thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disor ...
(HIT) or
thrombotic thrombocytopenic purpura Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that results in thrombi, blood clots forming in small blood vessels throughout the body. This results in a thrombocytopenia, low platelet count, hemolytic anemia, low red blood cells du ...
(TTP), that typically cause thromboses, or clots, instead of bleeding. Platelets release a multitude of growth factors including
platelet-derived growth factor Platelet-derived growth factor (PDGF) is one among numerous growth factor A growth factor is a naturally occurring substance capable of stimulating cell proliferation Cell proliferation is the process by which ''a cell grows and divides to ...
(PDGF), a potent chemotactic agent, and
TGF beta Transforming growth factor beta (TGF-β) is a multifunctional cytokine Cytokines are a broad and loose category of small protein Proteins are large biomolecule , showing alpha helices, represented by ribbons. This poten was the first ...
, which stimulates the deposition of extracellular matrix. Both of these growth factors have been shown to play a significant role in the repair and regeneration of connective tissues. Other healing-associated growth factors produced by platelets include
basic fibroblast growth factor FGF2, also known as basic fibroblast growth factor (bFGF) and FGF-β, is a growth factor A growth factor is a naturally occurring substance capable of stimulating cell proliferation Cell proliferation is the process by which ''a cell grows a ...
,
insulin-like growth factor 1 Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in tertiary structure, molecular structure to insulin which plays an important role in childhood growth, and has Anabolism, anabolic effects in adults. IGF-1 is ...
, platelet-derived epidermal growth factor, and
vascular endothelial growth factor Vascular endothelial growth factor (VEGF), originally known as vascular permeability factor (VPF), is a signal protein produced by many cells that stimulates the formation of blood vessels. To be specific, VEGF is a sub-family of growth factors, t ...
. Local application of these factors in increased concentrations through platelet-rich plasma (PRP) has been used as an adjunct to wound healing for several decades.


Complete blood count

A complete blood count (CBC) is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood. A scientist or lab technician performs the requested testing and provides the requesting medical professional with the results of the CBC. In the past, counting the cells in a patient's blood was performed manually, by viewing a slide prepared with a sample of the patient's blood under a microscope. Today, this process is generally automated by use of an automated analyzer, with only approximately 10-20% of samples now being examined manually. Abnormally high or low counts may indicate the presence of many forms of disease, and hence blood counts are amongst the most commonly performed blood tests in medicine, as they can provide an overview of a patient's general health status.


Discovery

In 1658 Dutch naturalist
Jan Swammerdam Jan Swammerdam (February 12, 1637 – February 17, 1680) was a Netherlands, Dutch biologist and microscopist. His work on insects demonstrated that the various phases during the life of an insect—Egg (biology), egg, larva, pupa, and adult— ...

Jan Swammerdam
was the first person to observe red blood cells under a microscope, and in 1695,
microscopist Microscopy is the technical field of using microscope A microscope (from grc, μικρός ''mikrós'' 'small' and ''skopeîn'' 'to look (at); examine, inspect') is a used to examine objects that are too small to be seen by the . is ...
Antoni van Leeuwenhoek
Antoni van Leeuwenhoek
, also Dutch, was the first to draw an illustration of "red corpuscles", as they were called. No further blood cells were discovered until 1842 when French physician Alfred Donné discovered platelets. The following year leukocytes were first observed by
Gabriel Andral Gabriel Andral (6 November 1797 – 13 February 1876) was a distinguished French pathologist and a professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary educati ...
, a French professor of medicine, and William Addison, a British physician, simultaneously. Both men believed that both red and white cells were altered in disease. With these discoveries,
hematology Hematology ( also spelled haematology in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial co ...
, a new field of medicine, was established. Even though agents for staining tissues and cells were available, almost no advances were made in knowledge about the morphology of blood cells until 1879, when
Paul Ehrlich Paul Ehrlich (; 14 March 1854 – 20 August 1915) was a Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel Alfred Bernhard Nobel ( , ; 21 October 1833  ...

Paul Ehrlich
published his technique for staining blood films and his method for differential blood cell counting.


References


External links

* {{DEFAULTSORT:Blood Cell 1658 in science Blood