Physiology of the Heart and Circulation Hemodynamics

This chapter deals with the function of the Heart as regards oxygenation at the level of the tissues and lungs. The phases of the Cardiac Cycle are discussed in detail, with accompanying schematic diagrams. Gaseous exchanges at the level of the tissues and alveoli are described. The pressure changes in the various chambers, oxygen saturation and blood flow pattern are described. Respiratory variations in cardiac flow and during the different maneuvers are elicited. The Heart sounds are discussed, Postural changes and venous return to the Heart are discussed. The effect of medications on the Heart is touched upon. The various indices to monitor the functioning of the Heart are described. The relationship between the Electrical and Mechanical activities of the Heart is described. Hemodynamic changes in normal and during Carotid Sinus Massage are analyzed. The role of precapillary sphincter in the blood supply to the various tissues of the body is discussed. After reading this chapter, the reader will become familiar with the different roles the heart plays in the body especially in the oxygenation process and removal of carbon dioxide and variation in the distribution of blood according to the need of the tissues and maintenance of homeostasis.