Objective 52 & 65: Kidney's involvement in blood pressure and blood volume regulation & State the importance of juxtaglomerular cells in secretion of renin

Since there was no in class lecture on the urinary system.  I basicaly ignored the onine lecture ecause it was boring and making my head hurt.  To help me some what understand objective 52 I used figure 24.12 in my textbook on page 849.  It helped in describing the process that affect blood pressure and blood volume. One way in which the kidneys maintain blood pressure is through the regulation of the volume of blood in the body. As the American Heart Association explains, one of the major roles of the kidneys is maintaining the proper levels of electrolytes (such as sodium and potassium) in the body. The amount of electrolytes in the body influences the amount of fluid in the body. When electrolyte levels are high, the body retains more water, which in turn increases the volume of the blood. More blood volume results in higher blood pressure. That is why the kidneys maintain blood pressure by indirectly controlling the amount of blood in the body.  The kidneys also regulate blood pressure hormonally. In order to do this, the kidneys must directly watch the blood pressure, which they do by measuring the amount of blood flow that the kidneys receive. This is where objective 65 comes in.  The juxtaglomerular cells are special renal cells. These cells are located in the arteries that feed into the kidneys. When blood flow to the kidney is reduced, a hormone called renin is excreted. This system can inadvertently lead to high blood pressure if the arteries leading to the kidney get narrowed because the juxtaglomerular cells will see it as low blood pressure even though blood pressure throughout the body is normal.