Tiêu đề Body Fluids and Circulation.pdf ✅

• Neutrophils (60-65%) of the total WBCs are phogocytic in nature. • Basophils (0.5-1 %), secretes histamine, serotonin and heparin and also involved in inflammatory reactions. • Eosinophils (2-3 %) resist infection and also associated with allergic reaction. • Lymphocytes (T cells and B cells) constitute 20-25 percent and involved in the immune response of the body. • Monocytes (10-15%), becomes macrophages. Thrombocytes : • Also known as blood platelets. • Produced from fragmentation of megakaryocytes. • Blood normally contain 1, 500, 00 – 3, 500, 00 platelets mm-3. • Involved in releasing thromboplastin required to initiate blood coagulation. BLOOD GROUPS : • Two blood grouping mechanisms ABO and Rh system. ABO grouping : • ABO grouping is based on the presence or absence of two surface antigens on the RBCs namely A and B. • Plasma of different individuals contains two natural antibodies, anti ‘A’ and ‘B’. • In a mismatched transfusion the antigen of the donor reacts with antibody of the recipient to cause a reaction calledclumping of agglutination. • Person with blood group ‘O’ has no antigen hence can donate blood anybody, called universal donor. • Person with blood group ‘AB’ has no antibody in his plasma hence can receive blood from anybody, called universal recipient. Rh grouping : • Another antigen, the Rh antigen similar to one present in Rhesus monkeys (hence Rh), is also observed on the surface of RBCs on majority (nearly 80 %). • Person with Rh antigen is said to be Rh positive (Rh+). • Person without Rh antigen is said to be Rh negative (Rh-). • Person with Rh- blood transfused with Rh+ blood, forms anti Rh antibody and destroy the Rh+ RBCs. • A special case of Rh incompatibility (mismatching) has been observed between the Rh- bloods of pregnant mother with the Rh+ blood of the foetus. • During parturition the Rh+ foetal blood mixed with the Rh- maternal blood, hence anti Rh antibody formed in mothers blood. • In successive pregnancy the anti Rh antibody from mother’s blood leaks into the foetal blood and destroy the Rh+ RBCs. 94 Free Downlod This

• Found in arthropods and mollusks. • Blood from the heart pumped into the open spaces in the body cavity called sinuses. • The body cavity remained filled with blood (haemolymph) called haemocoel. Closed circulatory system : • Found in annelids, echinoderms and all chordates. • Blood from the heart pumped into definite blood vessels. • Blood circulated in a wide network of blood vessel throughout the body. • Blood circulated in a regulated manner. Heart and circulation in vertebrates : • Fishes: have 2 chambered hearts with one atrium and one ventricle. • Amphibian and reptilian (except crocodile) has three chambered heart with two atria and one ventricle. • Crocodiles, birds and mammals possesses a 4-chambered heart with two atria and two ventricles • In fishes the two chambered heart pumped deoxygenated blood to the gills for oxygenation and then circulated to the body. (singlecirculation) • In amphibians and reptilians the left atrium receives oxygenated blood from the lungs and right atrium receives deoxygenated blood from the body. Blood from the atria pumped into the ventricle from which the mixed blood pumped into the body. (Incomplete double circulation). • In birds and mammals oxygenated and deoxygenated blood received by left and right atria respectively passed into ventricle of their side. The ventricles pump it out without any mixing up. (double circulation) HUMAN CIRCULATORY SYSTEM : Heart : • Originated from embryonic mesoderm. • Situated in the thoracic cavity, in between two lungs, slightly tilted towards left. • It has the size of the clenched fist. • Heart is covered by a double walled bag, pericardium. • Our heat is four chambered, two relatively smaller upper chamber called atria and two lower larger chamber calledventricles. • Two atria are separated by thin muscular wall called inter-atrial septum. • A thick walled inter-ventricular septum separates two ventricles. • Atrium and ventricle of same side is separated by a thick fibrous tissue called the atrio-ventricular septum. • Each of atrio-ventricular septa is provided with an opening through which the atrium and ventricle of same side are connected, called atrio-ventricular opening. • Right atrio-ventricular opening is guarded by tricuspid valve. • Left atrio-ventricular opening is guarded by bicuspid or mitral valve. • The right ventricle opens into systemic aorta and left ventricle opens into pulmonary aorta. • Both the aorta is guarded by semilunar valves. • The valves in the heart allow unidirectional flow of blood i.e. from atria to ventricles and from ventricles to their respective aorta. Conducting system of human heart : • The entire heart is made of cardiac muscles. • The wall of the ventricle is much thicker than the atria. • A patch of nodal tissue is present in the right upper corner of the right atrium called the Sino-atrial node(S A Node). • Another nodal tissue present in the posterior to the inter-ventricular septum called A V Node (Atrio-ventricular node). 96 Free Downlod This