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Read this term paper to learn about:- 1. Heart 2. Circulation of Blood 3. Blood Vessels 4. Maintenance by Platelets 5. Blood Grouping and Blood Transfusion 6. Lymph.
Term Paper # 1. Heart:
i. Location:
Heart is located behind the breastbone in the chest slightly offset to the left. Enclosed in a double walled sac called pericardium filled with pericardial fluid.
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ii. Four Chamber:
Upper chambers-right and left auricles, lower chambers-right and left ventricles.
iii. Valves:
a. Tricuspid:
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It is located between right auricle and right ventricle
b. Bicuspid:
It is located between left auricle and left ventricle.
c. Aortic Semilunar Valves:
It is located at the origin of arota from the left ventricle.
d. Pulmonary Semilunar Valves:
It is located at the opening of right ventricle into the pulmonary artery.
iv. Apertures:
a. Left Auriculoventricular Aperture:
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Let auricle and left ventricular.
b. Right Auriculoventricular Aperture:
Right auricle and right ventricular.
v. Blood Vessels:
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a. Leaving Artery:
It arises from right ventricle, carries deoxygenated blood to the lungs.
b. Arota:
It arises from left ventricle, carries oxygenated blood to all body parts.
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vi. Entering the Heart:
a. Superior Vena Cava:
It carries deoxygenated blood from head, chest and arms to right auricle.
b. Inferior Vena Cava:
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It carries deoxygenated blood from lower parts of the body to right artium.
Term Paper # 2. Circulation of Blood:
It is a bright viscous fluid that flows through all the vessels except lymph vessels. This process by which blood is formed is called hemostasis. The science that deals with the study of blood is called hematology. The main elements of blood are RBC, WBC, thrombocytes and plasma.
i. Erythrocytes (RBC):
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RBC is produced by erythropoiesis from bone marrow, liver and spleen. They are red in color due to the pressure of respiratory pigment called hemoglobin. Erythrocytes are spongy biconcave which varies in diameter 7-8 microns. The nature cells are devoid of nucleus, mitochondria and ER.
Hemoglobin (heam-iron, globin-protein):
They are to transport O2 to and CO2 from lungs via heart to organs of body and back to lungs. This is because they are smaller in size that helps them to travel through narrow capillaries. Hemoglobin is convex in shape giving the cell its capacity and surface area for absorption of gases. It lacks mitochondria that increase the efficiency of the RBC’s.
ii. Leucocytes (WBC):
WBC is produced by leucopoiesis. Leucocytes are nucleated cells that range from 8-20 microns.
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They are agranuclocyte and granulocytes:
A. Agranulocytes:
These are devoid of granules, developed from lymph nodes and red bone marrow. They are lymphocytes and monocytes. Lymphocytes have a round or slightly large nuclei while monocytes have kidney-shaped nuclei.
B. Granulocytes:
These develop from red bone marrow, have conspicuous granules in cytoplasm and possess lobbed nuclei. Eosinophil, basophil and neutrophil are examples of WBC.
(a) Eosinophil:
Nucleus is bilobed which are connected by a thin strand. Granules stain orange red with acidic dyes.
(b) Basophil:
Nucleus is large, bilobed or irregular in shape. Granules stain blue black with basic stains.
(c) Neutrophil:
These are most abundant-nuclei with 2-6 lobes connected via thin stands. Granules stain with natural dyes.
Function of Leucocytes:
a. Defence from foreign substance is a major function.
b. Phagocytosis involves neutrophils and monocytes. During an inflammation due to localized invasion of germs or injury, leucocytes gulp the germs and destroy them by phagocytosis.
c. Production of antibodies and antitoxins: Lymphocytes majorly produces antibodies and basophils.
d. Eosinophils produce antitoxins, which are chemicals that neutralizes bacteria products and hence are detoxifying agents.
e. Immunity is an ability of an organism to resist inflections.
iii. Thrombocytes: (Platelets):
Produced from giant cells in red bone marrow. Blood platelets oval numbering is between 2, 50,000 to 400000/mm with a life span of 5-9 days. Platelets lack nuclei.
Thrombocytes are also phagocytic and are capable of movements by producing pseudopodia. Platelets also release and take up certain chemical substances. These properties form the basis for their participation in celling of blood i.e. ability to stop bleeding.
Term Paper # 3. Blood Vessels:
i. Arteries:
Arteries are the muscular blood vessels that carry blood away from the heart to the organs. The pulmonary artery is the only exception as it carries deoxygenated blood to the lungs. The artery walls are so thick that when the blood enters under pressure, the walls can expand.
ii. Veins:
Veins carry deoxygenated blood to the heart. The only exception to this is in the pulmonary vein that carries oxygenated blood to the heart. Most of the blood volume is found in the venous system; about 70% at any given time. Veins have low blood pressure compared to arteries. Most veins have one-way valves called venous valves to prevent backflow caused by gravity.
iii. Capillaries:
Capillaries are the smallest of blood vessels; they connect arteries and veins and are in direct contact with tissues. The walls of capillaries are composed of a single layer of cells, the endothelium.
This is so thin that molecules such as oxygen, water and lipids can pass through them by diffusion and can enter the tissues. Waste products such as carbon dioxide and urea can diffuse back into the capillaries to be carried away for removal from the body.
Term Paper # 4. Maintenance by Platelets:
Platelets, which also called as thrombocytes, are membrane-bound cell fragments. Platelets lack a nucleus. The lifespan of a platelet is 8-10 days. The platelets have a sticky surface that allows them to accumulate at the site of broken blood vessels to form a clot.
This helps in the process of haemostasis (“stop bleeding”). When the blood vessel lining breaks, endothelial cells are damaged. This results in revealing the collagen proteins in the vessel wall. Platelets swell, grow spikey extensions, and start clumping together.
They start to stick to each other and the walls of the vessel. This continues as more platelets congregate and undergo these same transformations. This process results in a platelet plug that seals the injured area. If the injury is small, a platelet plug is formed and closes the blood loss in several seconds.
Term Paper # 5. Blood Grouping and Blood Transfusion:
RBC has antigens or agglutinogens on surface which are different for different types:
A group of people having blood with similar agglutinogens on its RBC are said to belong to same blood group.
Plasma, containing RBC contain antibodies called angulations.
The type of antigen determines the blood group that are of either A, B, AB or O. Antibodies in the blood plasma of an individual does not attack the antigen in RBC of the same individual.
Rh Factor Pregnancy:
Rh or Rhesus factor is a substance present in RBC. If it is present in the RBC, then the person is Rh positive and if it is absent in the RBC, then the person is Rh negative.
Term Paper # 6. Lymph:
It is a clear yellowish, slightly alkaline, coagulable fluid, containing white blood cells in a liquid resembling blood plasma. It is derived from the tissues of the body and conveyed to the bloodstream by the lymphatic vessels.
