Patho/Pharm II Study Guide
Structure and Function of the renal and urologic systems
Each kidney is composed of more than one million tiny, tightly closely packed nephrons. Each nephron consists of a glomerulus, where blood is filtered, and a proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct, where water, electrolytes, and other substances needed to maintain the constancy of the internal environment are reabsorbed into the bloodstream while other, unneeded materials are secreted into the tubular filtrate for elimination. The glomerulus is a high-pressure capillary filtration system located between two arterioles, the afferent and the efferent arterioles. It secretes renin and constriction is via Angiotensin II. Bowman’s capsule filters the blood. The tubules are where reabsorption takes place. Urine Formation begins with the glomerulus. The Loop of Henle controls the concentration of the urine. 
Ureters are self-sterilizing. Infections are ascending. Less signs and symptoms before detection.
Renal System and Electrolyte Balance
Elimination of sodium and potassium is regulated by the GFR (Glomerular Filtration Rate) and by hormonal agents that control their reabsorption. Aldosterone functions in the regulation of sodium and potassium elimination. Atrial natriuretic peptide contributes to the regulation of the sodium elimination. Sodium Reabsorption in the distal tubule and collecting duct is highly variable and depends on the presence of aldosterone. Almost all the sodium in the distal tubular fluid is reabsorbed, and the urine essentially becomes sodium free. Potassium is freely filtered in the glomerulus. It is reabsorbed from and secreted into the tubular fluid. This occurs in the distal tubule and is regulated by aldosterone. *Addison’s disease has an absence of aldosterone causing potassium minimal to get absorbed… this would mean that the potassium in the blood is going to be very high*
Cortex
Primary Function is filtration. This is where the glomeruli are located. It is incapable of regeneration. 
Medulla
It is the primary site of reabsorption and secretion. It concentrates the urine. The location of the renal tubular system. This is the site of drug induced toxicity which can happen through taking ACE, NSAID, Aminoglycosides, and Radiocontrast Dye.
Pelvis
It functions as urine storage. Collecting ducts empty, and it decreases the number of pathogens that can get through. This is the location of a kidney infection.

Diffusion
The movement of charged or uncharged particles along a concentration gradient. All molecules and ions, including water and dissolved molecules, are in constant random motion. It is the motion of these particles, each colliding with one another, that supplies the energy for diffusion.* Higher concentration to lower concentration*
Osmosis
The movement of water across a semipermeable membrane. As with solute particles, water diffuses down its concentration gradient, moving from one side of the membrane with greater concentration of water and lesser concentration of solute particles. As water moves across the semipermeable membrane, it generates osmotic pressure.
Active Transport
When cells use energy to move ions against an electrical or chemical gradient.
Albumin
 If there is albumin in urine, hypertension is likely to be the cause because high blood pressure causes high pressure in the glomerulus. Microalbumin is routinely assessed in diabetics. It is the earliest clinical indicator of renal malfunction. It is accompanied by nocturia. ACE Inhibitors are the medication of choice for microalbumin and ARB’s are the second choice.
Decreased plasma oncotic pressure may occur with decreased synthesis of plasma proteins or increased loss of plasma proteins. When these proteins are lacking, fluid seeps through the capillaries and accumulates in the tissues.
Renin
Released in response to low blood pressure, low blood volume, and when excretion is needed.
Angiotensin
This is the end product of the release of Renin. It tenses and constricts. It is associated with the growth hormone.
Renin-angiotensin-aldosterone mechanism
It is important for the long term and short term regulation of blood pressure. Renin acts as an enzyme to convert a circulating plasma protein to angiotensin I. This leaves the kidneys and enters the circulation. It gets to the lungs and converts to angiotensin II. This decreases salt and water excretion through vasodilation. Angiotensin II stimulates the secretion of aldosterone. This causes reabsorption of sodium in the distal tubule. All of this regulates blood pressure.

Causes of Edema
-Increased capillary permeability as a result of burns, trauma, or allergic and inflammatory responses
-Increased hysrostatic pressure from heart failure, pulmonary edema, and renal failure
-Malnutrition, nephrotic syndrome, and liver disease-decreased oncotic pressure
Sodium and potassium imbalances
Hypokalemia occurs with diuretic therapy. The potassium is below 3.5 mEq/L. Hyperkalemia occurs with potassium-sparing diuretics. The serum potassium is above 5 mEq/L. Excessive table salt and salty foods may aggravate edema or hypertension.
Urine Specimen
The correct method of obtaining a urine specimen is through a clean catch. Cleanse area. Start urinating, and midstream, stop and pee in the specimen container. 
Urine Specimen Contamination
Your history must match the urine test. The urine must be kept in the refrigerator and must not be older than 24 hours. Freshly voided specimens are most reliable. It shouldn’t have mold or rapidly growing bacteria in the urine. This means that it is contaminated. A urine specimen may contain- glucosides and nitrates/blood from kidney stone or infection, glucose and ketones.