Examination of Urine(physical properties & normal constituents)

Oct 2008Tahani Al-Shehri

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 )