Urinary system

• The urinary system consists of two kidents, the primary excretory organs 
• Kideny's excretory products are carried by a uretr to a single urinary bladder
• The urinary bladder is emptied of the water liquid by the uretha

Functions of the kidneys incluse 

• Excretion - the kideny filter waste products from the blood. 21% of cardiac output is filtered by the kidneys each minute 
• Regulation of blood volume and pressure - the kideny play a major role in controlling the extracellular fluif volume in the body. Kidney can produce either a large volume of dilute or a small volume of concentrated urine, depending on hydration level of the body. Through urine production, kidney regulate blood volume and hence blood pressure. 

Internal anatomy and Histology of the Kidneys 

• Organized into two major regions 1) outer cortex and 2) inner medulla that surrounds the renal sinus 
• Medulla is composed of many cone-shaped structures called renal pyramids, bases project the cortex. 
• Urine from several minor calyces are emptied into a larger, funnel shaped chamber called a major calx
• From the major calyces, urine empties into a single, enlarged, funnel shaped chamber called the renal pelvis 

Structures of a Nephron 

• The nephron is the histological and functional unit of the kidney 
• They are approximately 1.3 million nephrons distributed throughout the cortex and medulla of each kidney. 
• Nephrons usually measure 50-55 mm in length. 

Urine production 

• There are three major steps in urine production 1)filtration 2) tubular reabsorption 3)tubular secretion 
• Filtration - blood pressure in the glomerualr capillaries forces fluid and asmall molecules out of the blood. 
• Filtered…