Examination of Urine (physical properties & normal constituents) Oct 2008 Tahani Al-Shehri Examination of Urine (physical properties & normal constituents)

Objective : The simple examination of the Urine. To detect some of the normal organic constituents of urine. To detect some of the normal inorganic ions present in urine.

Introduction and Principle: Urine formation :- The basic steps in urine formation are : 1. Filtration. ( Glomerular) 2. Reabsorption.( Tubular) 3. Secretion. .( Tubular) 4. Excretion.

Kidney Function The main function of kidney is Homeostasis which means : -maintain internal environment constant -excretion of all metabolic west product.

Nephron

Glomerular filtration In a healthy adult about 650 ml of plasma (1200 ml of blood ) pass through functioning renal excretory tissue every minute, and about 125 ml of glomerular filtrate is formed.

Glomerular filtration Water passes freely from the plasma through the glomeruli , and those unbound constituents of the plasma that have a molecular weight of less than about 70,000 are present in the glomerular filtrate at the same concentration as in the plasma .

Glomerular filtration Substances of a higher molecular weight than about 70,000 do not pass freely through the glomeruli and are present in the glomerlar filtrate at a lower concentration than in plasma

Nephron

Tubular effect The renal tubules conserve water and soluble constituent of the body by reabsorption using both passive ( high conc. To low conc. ) And the active transport ( use ATP + carrier ) from the glomerular filtrate.

Simple examination of the urine Volume : The normal 24 hours Urine volume of an adult is between 750 and 2000 ml . This depend on the fluid intake loss of fluid by other routes.

Simple examination of the urine In Disease : Oliguria : Urine output less than 500ml/day Causese : deficient intake of water , or excessive loss of fluid by other routes , for example : by :haemorrhage , diarrhea vomiting

Simple examination of the urine Polyuria Urine output more than 2000m/day. Physiological causes chronic renal insufficiency . Polyuria of low osmolality is also found in diabetes insipidus Polyuria occur as an osmotic diuresis in any disease where there is an increased excretion of metabolites (diabetes mellitus ).

Simple examination of the urine Polyuria Physiological causes Excessive water intake Diuretic as tea, Cola, Coffee Excessive salt intake

Simple examination of the urine Colour : Due to urinary pigments (urochromes). Pale (low specific gravity ) to dark yellow (high specific gravity) Coloured urines occur in : certain disease metabolic disorders, after the administration of many drugs: Beta carotine supplement ( orange urine )

Simple examination of the urine  Appearance : Casts : The tubules secrete an α1-glycoprotein (Tamm-Horsfall protein ) , which , in the presence of albumin , comes out of solution in gel form as casts.

Simple examination of the urine Appearance : Mucus protein : This may be from semen or from vaginal discharge. Pathologically , it may be due to disease of the lower urinary tract or pus.

Simple examination of the urine Appearance : Crystals : These are not normally pathological Uric acid ( reddish – yellow) & calcium oxalate (colourless ) from acid urine phosphate ( whitish) from alkaline urine . Pathological cystine crystals dark reddish deposit of blood.

Simple examination of the urine Smell: unpleasant smell : urine infected with Gram-negative organisms . ammonical smell: urine infected with urea splitting organisms maple syrup disease (H.W)

Simple examination of the urine pH: Normal between 5.5 and 8 Alkalosis : Vegetarine diet Bacterial infection

Simple examination of the urine Specific Gravity : normal specific gravity in 24 hour urine sample is between 1.025 and 1.010 Wt of the sample / Wt of the water High urine volume ( low Sp.gravity ) low urine volume ( high Sp.gravity )