Year: 2015

This video is about Mechanism of Heart. This mechanism can be divided into heart beat and cardiac cycle. Continuous beating of heart is known as cardiac cycle. It takes 0.8 sec. This mechanism is controlled by heart conducting system (HCS). HCS=SAN+ AVN+ Bundle of his + Purkinjee fibers.

Pearl is only gem stone which is produced by living animals. Pearl formation is a biological process in which pearl is formed by living animals against an irritant in the body of Oysters. The most productive Oyster is Pinctada vulgaris. The pearl develop in between shell and mantle of oyster. The layers of nacre develop into the pearl. It is made up of calcium carbonate and chonchiolin. The pearl may be natural and artificial. The peal culture industry is developed in Japan. It may be white, black, grey, red, green and blue in colour. The black coloured pearl is most rare and precious. It is used in jewelry.