دكتر محمدرضا مرواريدي كارشناس اداره امور بيماريهاي خاص

KIDNEYS AND THE URINARY SYSTEM

food, water intakeoxygen intake elimination of carbon dioxide Digestive SystemRespiratory System Circulatory System Urinary System elimination of excess water salts, wastes rapid transport to and from all living cells elimination of food residues nutrients, water, salts carbon dioxide water solutes oxygen Based on: Starr, C., Biology: Concepts and Applications, Brooks/Cole

 Separation of wastes from body fluids and eliminating them  respiratory system: CO 2  integumentary system: water, salts, lactic acid, urea  digestive system: water, salts, CO 2, lipids, bile pigments, cholesterol  urinary system: many metabolic wastes, toxins, drugs, hormones, salts, H + and water

 Filters blood plasma, eliminates waste, returns useful chemicals to blood  Regulates blood volume and pressure  Regulates osmolarity of body fluids  Secretes renin, activates angiotensin, aldosterone  controls BP, electrolyte balance  Secretes erythropoietin, controls RBC count  Regulates P CO 2 and acid base balance  Detoxifies free radicals and drugs  Gluconeogenesis

Diuretic- loose water; coffee, alcohol Antidiuretic- retain water; ADH Aldosterone- sodium & water reabsorption, and K + excretion GFR= 180 liters (50 gal) of blood/day liters are reabsorbed back into blood Excrete a protein free filtrate

All 20 amino acids have a nitrogen group (NH 2 ). When broken down for energy, the nitrogen group is converted to ammonia (NH 3 ). Examples of Amino Acids

Ammonia is converted into urea by the liver. Urea is then transported in the blood to the kidneys where the urea is removed from the blood. Circulatory System Based on: Mader, S., Inquiry Into Life

 Urea  proteins  amino acids  NH 2 removed  forms ammonia, liver converts to urea  Uric acid  nucleic acid catabolism  Creatinine  creatinine phosphate catabolism  Amonia N ـــــ H 3

Urinary System Based on: Mader, S., Inquiry Into Life, McGraw-Hill

 Position, weight and size  retroperitoneal, level of T 12 to L 3  about g each  about size of a bar of soap (12x6x3 cm)  Shape  Bean shape  lateral surface - convex; medial - concave

Anatomy of the Kidney Based on: Mader, S., Inquiry Into Life, McGraw-Hill

Glomerular filtrate collects in capsular space, flows into renal tubule

Nephron Based on: Mader, S., Inquiry Into Life, McGraw-Hill

REGULATION OF WATER BALANCE Brain monitors water content of blood If low water content, pituitary releases ADH ADH travels in blood to nephron ADH causes more water to move from urine back into blood

Nephron Based on: Mader, S., Inquiry Into Life, McGraw-Hill

 GFR, urine output rises  dehydration, electrolyte depletion  GFR  wastes reabsorbed (azotemia possible) GFR controlled by adjusting glomerular blood pressure – hormonal mechanism: renin and angiotensin – autoregulation – sympathetic control

low blood volume high plasma solute concentration hypothalamus heart receptors

hypothalamus posterior pituitary antidiuretic hormone collecting ducts

reduced blood pressure and glomerular filtrate juxtaglomerular apparatus renin

reninangiotensinogen angiotensin I angiotensin II

adrenal cortex aldosterone angiotensin II convoluted tubules

-efferent arterioles

- vasomotion - monitor salinity

  BP  constrict afferent arteriole, dilate efferent   BP  dilate afferent arteriole, constrict efferent  Stable for BP range of 80 to 170 mmHg (systolic)  Cannot compensate for extreme BP

 Strenuous exercise or acute conditions (circulatory shock) stimulate afferent arterioles to constrict   GFR and urine production, redirecting blood flow to heart, brain and skeletal muscles

 Normal volume - 1 to 2 L/day  Polyuria > 2L/day  Oliguria < 500 mL/day  Anuria - 0 to 100 mL

Daily filtrationActual excretion Water180 liter1.5 liter Salts700 gm15 gm Glucose170 gm0 Urea50 gm30 gm Contents of urine Urine –Daily output 1200 to 1500 ml –95 % water, 5 % salts & organic matter –Urea, uric acid, salts of potassium, magnesium and calcium

Why do doctors ask for a urine sample? Urinalysis characteristics: smell- ammonia-like pH , ave 6.0 specific gravity– more than 1.0; ~ color- affected by what we eat: salty foods, vitamins

Glucose- when present in urine condition called glycosuria (nonpathological) [glucose not normally found in urine] Indicative of: Excessive carbohydrate intake Stress Diabetes mellitus Abnormal Constitutes of Urine

Albumin-abnormal in urine; it’s a very large molecule, too large to pass through glomerular membrane > abnormal increase in permeability of membrane Albuminuria- nonpathological conditions- excessive exertion, pregnancy, overabundant protein intake-- leads to physiologic albuminuria Pathological condition- kidney trauma due to blows, heavy metals, bacterial toxin Abnormal Constitutes of Urine

Ketone bodies- normal in urine but in small amts Ketonuria- find during starvation, using fat stores Ketonuria is couples w/a finding of glycosuria-- which is usually diagnosed as diabetes mellitus RBC-hematuria Hemoglobin- Hemoglobinuria- due to fragmentation or hemolysis of RBC; conditions: hemolytic anemia, transfusion reaction, burns or renal disease Abnormal Constitutes of Urine

Bile pigments- Bilirubinuria (bile pigment in urine)- liver pathology such as hepatitis or cirrhosis WBC- Pyuria- urinary tract infection; indicates inflammation of urinary tract Casts- hardened cell fragments, cylindrical, flushed out of urinary tract WBC casts- pyelonephritus RBC casts- glomerulonephritus Fatty casts- renal damage Abnormal Constitutes of Urine