renal sysytem

renal sysytem

1. anatomy and physiology of renal system

   • Nephron : Performs 3 tasks: Glomerular filtration, Tubular reabsorption, Tubular secretion. Consists of: Glomerulus, Bowman’s capsule, Proximal convoluted tubule, Loop of Henle, Distal convoluted tubule, Collecting duct

2. Functions of the kidneys

   • two kidneys, size of fist
     • back of abdominal cavity
   • The main functions of the kidneys are the removal of toxic waste products from the blood
     • maintaining homeostasis in the body by controlling pH levels, the concentration of electrolytes, the volume of extracellular fluid and the regulation of blood pressure

3. Waste products = urea and uric acid

   • composition of urine: 95% water & 5 % solutes (urea, Na+, K+, Creatnine & uric acid)
     • ADH (prevents excessive water loss in the urine)
       • Aldosterone (regulates the sodium ion content in ECF).
         • When not enough Na, blood becomes diluted, water leaves the bloodstream and flows into the tissue space = oedema
           • Thirst mechanism: is the driving force for water intake. A rise in plasma solutes excites the hypothalmic thirst centre
             • Buffers: chemical buffers prevent dramatic changes in hydrogen ion concentrations

4. Medications

   • Diuretics
     • increase urine production
       • Used in people who retain water and sodium chloride - oedema
     • nursing considerations
       • given early in the day to prevent nocturia
       • 2nd dose given at midday
       • FBC - monitor input and output
       • daily weights
       • may have lying and standing BP
       • daily or BD bloods
       • diahorea and vomiting may have to withhold diuretic
     • Thiazide - inhibits reabsorption of sodium and chloride - increased excretion of potassium
       • Loop diuretics: increases excretion of potassium, frusemide (Lasix)