Here we will explain about blood, blood characteristics, blood function, blood composition, physiology of blood and mechanism of blood clotting. Blood is liquid substance which flow in blood vessels.
Blood is a fluid which travels in blood vessels i.e. arteries and veins. Blood delivers several necessary substances such as oxygen and nutrients to the cells and transports waste metabolic products away from cells.
What is oxygenated blood
Blood is composite with several elements such as white blood cells, red blood cells, platelets and blood plasma. Red blood cells are composite with hemoglobin. Hemoglobin is containing four heme molecules, four oxygen molecules are attached to each heme molecules. Hemoglobin attached oxygen molecules, called oxyhemoglobin. Blood carry oxygen molecules and transport in to the cells, blood carry oxygen molecules called oxygenated blood. Oxygenated blood is travel in artery. In artery, blood color is brighter red due to oxyhemoglobin.
What is deoxygenated blood ?
Living cells perform various metabolic reactions, between these reaction they release various metabolic waste products such as carbon-di-oxide. Blood carry carbon-di-oxide molecules called deoxygenated blood. Deoxygenated blood is travel in veins. Blood color in vein is darker red than artery.
Characteristics Of Blood
- Blood is a type of connective tissue.
- Blood pH is 7.4.
- Blood has red color – Brighter red in artery and Darker red in vein
- Blood is 7% of the human body weight.
- The average adult has a blood volume about 5-6 liters.
Function Of Blood
Blood is play vital role in living body. blood involve in various mechanism and physiology of human body. the functions of blood is following -
Transportation -
- Blood transport various essential elements to cells, these elements are necessary for many metabolic reactions.
- Blood carry oxygen to cells and take back carbon dioxide to lungs.
- Blood carrier for many hormone and enzymes.
- Blood transport nutrition and essential elements to cells for growth and development.
Regulation -
- Blood help maintain homeostasis of all body fluids.
- Blood maintain pH through using buffers. Blood also regulate body temperature.
Protection -
- Blood make a gel like structure, called clot, which protect against blood excessive loss from the Cardiovascular System after the injury.
- Various type of blood cells protect against disease in a variety of ways.
- White blood cells protect against disease by phagocytosis.
Composition Of Blood
Blood is composed of blood plasma and blood cells (formed elements). Blood plasma, which constitutes 55% volume of whole blood, is mostly water about 91.5% of total plasma and contains plasma proteins such as albumin, globulin and fibrinogen about 7% part of total blood plasma. Blood plasma also contains other solutes (about 1.5% total of blood plasma) such as nutrients (Amino acids, glucose, vitamins and minerals), electrolytes (sodium, potassium, chloride, suphate, magnesium ions and so on), regulatory substance (hormone, enzymes and vitamins), gases and waste products (urea, uric acid, creatinine, ammonia etc).
Blood cells, which constitutes 45% volume of blood. Three types of blood cells present in blood. Red blood cells, white blood cells and platelets are composed blood cells.
Water (91.5-92% of total blood plasma) |
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Plasma proteins (7% of total blood plasma)
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Albumin (54% of total plasma protein)
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Globulin (38% of total plasma protein)
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Alpha globulin's - Liver
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Large in size
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Maintain osmotic concentration, transport
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Beta globulin's - Liver
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transport, regulate osmotic concentration
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Gamma globulin's or immunoglobulins - Plasma cells
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Immune response
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Fibrinogen (7 of total plasma protein)
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Other solutes (1.5% of total blood plasma)
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Electrolytes
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Nutrients
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Gases
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Regulatory substances
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various sources
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Waste products
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Red blood cells ( In male - 5.4 million/micro-liter.
In female - 4.8 million/micro-liter) |
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Red bone marrow
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Size - 10-12 micrometer.
Nucleus has 2 to 5 lobes |
Phagocytosis
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Eosinophils (2-4% of all leukocytes)
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Red bone marrow
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Size - 10-12 micro-meter.
Nucleus has 2 lobes. |
Fight effect of histamine in allergic reactions
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Red bone marrow
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Size - 10-12 micro-meter.
Nucleus has 2 lobes |
Discharge histamine, heparin and serotonin in allergic reactions which produce inflammatory response
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Agranular leukocytes
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Bone marrow and lymphatic tissue
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Nucleus is rounded and slightly intended
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Specific immunity, natural killer cells attack wide variety of infectious microbes.
B cells develop into plasma cells which secrete antibodies. T cells attack cancer cells, viruses, and transplanted tissue cells. |
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Red bone marrow
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Size - 12-20 micro-meter.
Nucleus is horseshoe or kidney shaped |
Nonspecific immunity.
phagocytosis |
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Platelets (150,000-400,000 micro-liter)
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Red bone marrow
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Size - 2-4 micro-meter in diameter.
Life period - 5-9 days. No nucleus |
Promote blood clotting.
From platelets plug in hemostasis |
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Physiology Of Blood
Deoxygenated blood comes from cells and tissues in right atrium through superior vena cava (collect blood from upper region of body), inferior vena cava (collect blood from lower region of body) and coronary sinus (collect blood from heart cells). Deoxygenated blood fill in right atrium and tricuspid valve is open. Blood transfer into right atrium.
Deoxygenated blood goes lungs through pulmonary artery, where deoxygenated blood is change into oxygenated blood (oxygen bind to hemoglobin molecules of blood). Oxygenated blood is transfer from lungs to left atrium through pulmonary vein. Bicuspid valve is open and blood transfer to left ventricle. Oxygenated blood is send to all body cells and tissues by arch of arota. Coronary artery supply oxygenated blood to heart tissues.
Blood Clotting Mechanism
Blood is flow in vessels in liquid form. When blood is drawn from body, it thickens and forms a gel like structure. The gel is called clot.
Insoluble protein fibers, i.e. fibrin trapped the elements of blood and make clot.
The gel is separates from liquid, that liquid is serum and gel is clot.
Blood clotting has three stages to form a clot:
Stage 1: Formation of prothrombinase enzyme by two different pathway;
- Extrinic pathway
- Intrinsic pathway
Stage 2: In the presence of prothrombinase enzyme and calcium, prothrombin (Clotting factor II) converts in thrombin.
Stage 3: Thrombin in the presence of calcium, converts in fibrinogen. Thrombin also activates clotting factor XIII. In the presence of Factor XIII, Fibrin threads make clot.
First step is different in both pathways. The steps are involved in the next two stages of clotting are the similar.
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| Mechanism of blood Clotting |
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