Human Immunity and Blood

Hemophila A is associated with episodes of bleeding. Current treatment involves infusion of factor VIII to promote blood clotting during a bleeding episode.

The B is ABO type and + is an Rh type (Rh positive). While these are medically the most important blood type systems, similarly we all have many others that we could typed for as well.

The International Society of Blood Transfusion (ISBT) identifies about 30 major blood group systems, including the ABO and Rh systems.

Lymphoid stem cells derived from the bone marrow develop into competent T-lymphocytes with a functioning T-cell receptor and coreceptor in the thymus gland.

Immunoglobulins are produced by lymphocytes.

Thrombocytopenic purpura is characterized by excessive bleeding due to insufficient platelets. The term 'thrombocytopenic' literally means low platelet count, which prevents proper blood clotting and leads to spontaneous bruising and bleeding.

Megakaryocytes are large, specialized cells in the bone marrow that produce platelets (thrombocytes) through fragmentation of their cytoplasm. They do not produce erythrocytes (from erythroblasts), granulocytes (from myeloblasts), or agranulocytes (from lymphoblasts).

RBCs are primarily destroyed in the spleen and liver by macrophages, while WBCs (particularly lymphocytes) are destroyed in various tissues throughout the body. The spleen is a major site for lymphocyte destruction during immune regulation, though other lymphoid tissues also participate.

Histamine is primarily stored and released by mast cells (found in connective tissue) and basophils (a type of granulocyte). Macrophages and Kupffer cells are phagocytic cells involved in antigen presentation and debris clearance, not histamine secretion.

Platelets (thrombocytes) are not true cells but small, anucleate cell fragments derived from megakaryocytes. Monocytes, neutrophils, and basophils are all complete, nucleated white blood cells (leukocytes).

Blood group A has A antigens on red blood cells and anti-B antibodies in plasma. The ABO system is based on the presence or absence of A and B antigens on RBC surfaces. Blood type A has only A antigens, type B has only B antigens, type AB has both, and type O has neither.

Lymph glands primarily filter lymph, produce lymphocytes and antibodies, and help fight infections by trapping pathogens. The destruction of red blood cells occurs mainly in the spleen and liver, making this the correct choice as it is NOT a primary function of lymph nodes.

Haemoconia refers to small, granular particles occasionally observed in blood plasma, distinct from platelets which are cellular components involved in clotting. Chylomicrons are lipoprotein particles transporting dietary lipids, and chyluria indicates a milky appearance of urine due to lymph presence.

The liver synthesizes major plasma proteins including albumin (maintains oncotic pressure), fibrinogen (essential for clotting), and prothrombin (a clotting factor). This protein synthesis function is exclusive to hepatocytes, distinguishing the liver from other organs listed.

Agranulocytes are white blood cells lacking visible cytoplasmic granules, primarily lymphocytes and monocytes. In contrast, eosinophils, basophils, and neutrophils are granulocytes, each containing distinctive granules that give them their staining properties and functional characteristics.