1. Laboratory diagnostics of urine

2. The kidneys are bean shaped organs that serve several essential regulatory roles in vertebrate animals. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and regulation of blood pressure (via maintaining salt and water balance). They serve the body as a natural filter of the blood, and remove wastes, which are diverted to the urinary bladder. In producing urine, the kidneys excrete wastes such as urea and ammonium, and they are also responsible for the reabsorption of water, glucose, and amino acids. The kidneys also produce hormones including calcitriol, erythropoietin, and the enzyme renin.

3. Urine formation Structures responsible for the urine formation:
glomeruli,
proximal canaliculi,
distal canaliculi.
Mechanism of urine formation:
filtration
reabsorption
secretion

4. The urinary system, also known as the renal system, consists of the two kidneys, ureters, the bladder, and the urethra. Each kidney consists of millions of functional units called nephrons. The purpose of the renal system is to eliminate wastes from the body, regulate blood volume and pressure, control levels of electrolytes and metabolites, and regulate blood pH. The kidneys have extensive blood supply via the renal arteries which leave the kidneys via the renal vein. Following filtration of blood and further processing, wastes (in the form of urine) exit the kidney via the ureters, tubes made of smooth muscle fibers that propel urine towards the urinary bladder, where it is stored and subsequently expelled from the body by urination. The female and male urinary system are very similar, differing only in the length of the urethra.

5. Mechanisms of elimination:
filtration
reabsorption
excretion

6. The kidneys cleanse the blood plasma of metabolic products
The kidneys cleanse the blood plasma of metabolic products. In addition, through the kidneys excreted substances necessary for the life of the body - water, sodium ions, calcium phosphates - in the case where the concentration in the blood than normal. Thus, the function of the kidneys is to remove a sample of various substances in order to maintain the relative constancy of the chemical composition of blood plasma and extracellular fluid.

7. Filtration About 120 mL/min or 180 L/day of blood is filtrated.
Takes place in glomeruli.
Substances with molecular mass below 40,000 Da pass through the membrane of glomerulus into capsula.
About 120 mL/min or 180 L/day of blood is filtrated.
Filtration – passive process.
After filtration – primary urine (180 L/day)

8. Filtering. In renal glomeruli all low-molecular substances such as glucose, water and urea, go into the filtrate, filling boumenova capsule and then has to renal tubule of the nephron.   Ultrafiltration rate is fairly constant - 1 min produced about 125 ml of the filtrate. If all the filtrate was removed in the form of urine, its volume per day would amount to about 180 liters. However, 124 ml of the filtrate is sucked back.

9. Filtration is caused by:
-hydrostatic pressure of blood in capillaries of glomeruli (70 mm Hg)
-oncotic pressure of blood plasma proteins (30 mm Hg)
-hydrostatic pressure of ultrafiltrate in capsule (20 mm Hg)
70 mm Hg-(30 mm Hg+20 mm Hg)=20 mm Hg
Hydrostatic pressure in glomeruli is determined by the ratio between diameter of ascendant and descendant arteriole

10. Reabsorption Takes place in proximal and distal canaliculi.
What is reabsorbed? Glucose (100%), amino acids (93%), water (98%), NaCl (70%) etc.
The urine is concentrated (toxins damages the proximal canaliculi)
Reabsorption:
active
passive.
Lipophilic substances - passive.
Na/K АТP-аse is very active

12. Reabsorption. All substances that may be used by the body or the need to maintain water and electrolyte composition of body fluids are absorbed from the filtrate into the blood capillaries in the proximal convoluted renal tubule.

13. Secretion Takes place in proximal and distal canaliculi. Secretion:
Transport of substances from blood into filtrate.
Takes place in proximal and distal canaliculi.
Secretion:
active
passive.
Passive secretion depends on the pH.
What is secreted?
Ions of K, аmmonia, H+
drugs
xenobiotics

14. CLEARANCE Clearance = (C urine/C plasma) * V
Clearance of any substance is expressed in ml of blood plasma that is purified from this substance for 1 min while passing through the kidneys.
About 180 L of primary urine is formed for 1 day, about 125 mL of primary urine for 1 min.
Glucose is reabsorbed completely; clearance = 0
Inulin is not reabsorbed absolutely; clearance = 125 mL/min
If clearance is more than 125 mL/min the substance is secreted actively.
Clearance = (C urine/C plasma) * V

15. Clearance (born clearance - purification) or purification factor - speed indicator purification of biological fluids or tissues of the body from the substance during its biotransformation redistribution in the body, and excretion.

17. MAINTAINING OF ACIDIC-BASE BALANCE BY KIDNEYS
Three mechanisms:
Conversion of two substituted phosphates into one substituted in the cavity of canaliculi
Formation of carbonic acid in the cells with the following dissociation to Н+ and НСО3-
ammonia excretion

18. MAINTAINING OF ACIDIC-BASE BALANCE BY KIDNEYS
Cells of canaliculus
Blood
Cavity of canaliculus
Na2HPO4
Na+
Na+
Na+
Na+
HPO42- H+ H+
NaH2PO4

20. MAINTAINING OF ACIDIC-BASE BALANCE BY KIDNEYS
Cells of canaliculus
Blood
Cavity of canaliculus
NaHCO3
Na+
Na+
Na+ H+ H+
HCO3-
HCO3-
H2CO3
H2CO3
H2O +
CO2
H2O
CO2

21. MAINTAINING OF ACIDIC-BASE BALANCE BY KIDNEYS
Cells of canaliculus
Blood
Cavity of canaliculus
Glutamine
NH3
NH3+H+
Glutamic acid
NH4+

23. Urine (from Latin Urina, ae, f
Urine (from Latin Urina, ae, f.) is a typically sterile liquid by-product of the body secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream. These by-products are eventually expelled from the body during urination, the primary method for excreting water-soluble chemicals from the body. These chemicals can be detected and analyzed by urinalysis. Certain disease conditions can result in pathogen-contaminated urine

24. COLLECTION OF URINE:
For biochemical investigations, urine can be collected as a single specimen or for 24 hours. Single specimens of urine, normally collected in the morning, are useful for qualitative tests e.g., sugar, proteins.

25. Urine specimens tend to deteriorate.
The changes include:
1. destruction of glucose by bacteria;
2. conversion of urea to ammonia, by bacte­ria, with fall in [H+] and precipitation of phosphates;
3. oxidation of urobilinogen to urobilin and porphobilinogen to porphyrins.

26. Preservatives for urine : The preservatives are used (1) to reduce bacterial action; (2) to minimise chemical decomposition, and (3) to decrease atmospheric oxidation of unstable compounds.
Formalin, thymol, chloroform, toluene, concentrated HCI and glacial acetic acid are the commonly used urine preservatives.

28. Transparency – transparent
PROPERTIES OF URINE
Amount – mL/day
Poliuria – diabetes mellitus and insipidus
Oliguria – heart failure, nephritis, vomiting, fever
Anuria – kidney failure, acute intoxication by heavy metals
Color – straw-yellow
Pale – poliuria (diabetes insipidud)
Dark – jaundice, concentrated urine
Red – blood available
Green-blue – decay of proteins in the intestine
Transparency – transparent
Cloudy – pus or mucin available

29. Density – 1,003-1,035 g/mL
Increased density – organic or inorganic substances available (diabetes mellitus)
Decreased density – diabetes insipidus
Isostenuria – continuously low density in oliguria (kidney failure)
pH –
Acidic – meat food, diabetes mellitus, starvation, fever
Alkaline – plant food, cystitis, pyelitis