Body Fluids and Circulation Test - 6

Monocytes are a type of white blood cells that fight certain infections and help other white blood cells remove dead or damaged tissues, destroy cancer cells, and regulate immunity against foreign substances.

Tunica media is middle thick coat of circularly disposed smooth or un-striped muscle fibres and elastic fibres. The thick coat prevents arteries from collapsing.

Plasma does not bind oxygen. Haemoglobin in blood binds oxygen and carries it to different body parts.

Red blood cells are absent in the Antarctic icefish. They live in high oxygen-rich cold water and transport oxygen freely dissolved in their blood.

Phosphatidylcholine is present in the outer layer. Phosphatidylcholine plays a prominent role in membrane-mediated cell signaling and also in phosphatidylcholine transfer protein (PCTP) activation of other enzymes.

Basophils have either bi- or tri-lobed nuclei. Mostly, the nucleus is two-lobed.

Phospholipids, calcium and vitamin K are required for blood clotting. Calcium and phospholipids are required for the tenase and prothrombinase complexes to function. Calcium is also required at other points in the coagulation cascade. Vitamin K serves as an essential cofactor for a carboxylase that catalyses carboxylation of glutamic acid residues on vitamin K-dependent proteins. Without vitamin K, the carboxylation does not occur and the proteins (clotting factors like factors II (prothrombin), VII, IX and X) that are synthesised are biologically inactive.

A universal donor has neither A nor B antigen on the surface of RBC.

HDN due to ABO incompatibility is usually less severe than Rh incompatibility. One reason is that fetal RBCs express less of the ABO blood group antigens compared with adult levels. In addition, in contrast to the Rh antigens, the ABO blood group antigens are expressed by a variety of fetal (and adult) tissues, reducing the chances of anti-A and anti-B binding their target antigens on the fetal RBCs.

The function of the chordae tendineae is to limit the freedom of motion of the cusps of the AV valves limiting their capacity to "flap" back into the corresponding atrium.