Blood cell
A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a
Red blood cells
Red blood cells or erythrocytes, primarily carry oxygen and collect carbon dioxide through the use of hemoglobin.[2] Hemoglobin is an iron-containing protein that gives red blood cells their color and facilitates transportation of oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs to be exhaled.[3] 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 in a process known as erythropoiesis. 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.
Mature red blood cells are unique among cells in the human body in that they lack a nucleus (although
The condition of having too few red blood cells is known as anemia, while having too many is polycythemia.
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 cells are divided into
The condition of having too few white blood cells is
Platelets
The normal range (99% of population analyzed) for platelets is 150,000 to 450,000 per cubic millimeter.[6] 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, myocardial infarction, 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), 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 (HIT) or thrombotic thrombocytopenic purpura (TTP), that typically cause thromboses, or clots, instead of bleeding.
Platelets release a multitude of growth factors including
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
References
- ISBN 0-13-981176-1.
- ISBN 978-0-323-42796-8.
- ^ Basic Biology (2015). "Blood cells".
- ISBN 0-8153-4072-9.
- ISBN 978-1416031215.
- PMID 3414599.
- PMID 12817630.
External links
- Media related to Blood cells at Wikimedia Commons