Blood and Circulation

Blood flow is the continuous running of blood in the cardiovascular system. The human body is made up of several processes all carrying out various functions. We have the gastrointestinal system which aids the digestion and the absorption of food. We also have the respiratory system which is responsible for the absorption of O2 and elimination of CO2. The urinary system removes waste from the body. The cardiovascular system helps to distribute food, O2 and other product of metabolism. The reproductive system is responsible for perpetuating the species. The nervous and endocrine system is  responsible for coordinating the integration and function of other system.

Blood is the viscous fluid composed of plasma and cells. The composition of the blood includes plasma, red blood cells, white blood cells and platelets. In the microcirculation the properties of the blood cells have an important influence on flow.

Mechanics is the study of motion (or equilibrium) and the forces that cause it. The blood moves in the blood vessels, while the heart serves as the pump for the blood. The vessel walls of the heart are elastic and are movable, therefore causing the blood and the wall to exert forces on each other which in turn influence their respective motion.

Therefore to understand the mechanics of circulation of the heart, it will be worth the while to go through a review of basic mechanics of fluid, and elastic solids (momentum) and the nature of the forces exerted between two moving substances in contact.

The white blood cells are also referred to as the leucocytes. The leucocytes (the white blood cells) constitute less than 1% of the total blood cell volume in humans. The basic function of the leucocytes is to attack and destroy potentially harmful foreign matter.

The red blood cells also called the erythrocytes. These constitute between 38 and 48 percent of the whole blood. These cells keep the tissue alive by bringing oxygen to it and taking carbon dioxide away.

The Urinary system

The urinary system or renal system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two urethras, the bladder and the urethra. The female and male urinary system are very similar, differing only in the length of the urethra

Urine is formed in the kidneys through a filtration of blood. The urine is then passed through the urethras to the bladder, where it is stored. During urination (peeing) the urine is passed from the bladder through the urethra to the outside of the body.

About 1-2 liters of urine are produced every day in a healthy human, although this amount may vary according to circumstances such as fluid intake.

There are several functions of the Urinary System:
01-    Removal of waste product from the body (mainly urea and uric acid)
02-    Regulation of electrolyte balance (e. g. sodium, potassium and calcium)
03-    Regulation acid-base homeostasis
04-    Controlling blood volume and maintaining blood pressure
The first step in urine formation is the filtration of blood in the kidneys. In a healthy hum the kidney receives between 12 and 30% of cardiac output, but it averages about 20% or about 1.25 L/min. The basic structural and functional unit of the kidney is the enthroned. Its chef function is to regulate the concentration of water and soluble substance like sodium salty by filtering the blood, read-sobbing what is needed and excreting the rest as urine.