Urinary System

Kidney Transplant IZc IZc

Major Parts of the Urinary System Kidney – Retroperitoneal – About the size of a fist – Weighs from 4-6 lbs – Cortex – Medulla – Hilum

Major Parts of the Urinary System Ureter – Two hollow tubes – 16”-18” long – Kidneys to urinary bladder Urinary bladder – A hollow sac – Temporary reservoir – Trigone Region at the base Ureters enter, urethra exits

Major parts of the Urinary System Urethra – Urine to bladder to outside of bladder – Urination – Urinary meatus – Female urethra is about 1 ½” long – Male is about 8” long

1,000,000 Nephrons!!!! Units in which kidney functions are performed Each kidney contains more nephrons than one person needs This is why people can live a normal life with ONE kidney!

How do kidneys produce urine? Renal arteries – Enters kidneys from the aorta Arterioles – Blood passes through slowly and constantly Renin – Blood flow decrease, kidney produces renin, causing an increase in blood pressure, and a return of normal blood flow Glomeruli/glomerulus – Tiny, coiled, intertwined smaller blood vessels – ~1 million in the cortex of each kidney

How do kidneys produce urine? Filtration – As the blood passes through the glomeruli, water, salts and urea and other waste products leave the blood stream Creatinine and uric acid – Waste products from the bloodstream Bowman’s capsule – Surrounds each glomerulus – Waste products collect – Prevents large substances (proteins and blood cells) from filtering into the capsule

How do kidneys produce urine? Renal tubule – Attached to each Bowman’s capsule – Water, sugar, salts, urea and other wastes pass through; MOST water, ALL sugar, SOME salts return to bloodstream – All collecting tubules lead to the renal pelvis Reabsorption – Active process, ensures the body retains essential substances such as sugar, water and salts

How do kidneys produce urine? Secretion – Final process – Waste products become toxic if they are allowed to accumulate in the body – Waste products (acids, drugs, potassium) leave the body in urine

Formation of Urine Three steps – Glomerular filtration – Tubular reabsorption – Tubular secretion Nephron – Glomerulus + Renal tubule = 1 unit

Formation of urine Leaving the body – Renal pelvis narrows into the ureter – Ureter carries urine to bladder – Bladder stores urines – As bladder fills, pressure increases at the base – Individual notices the need to urinate, voluntary relaxation causes the sphincter muscles to relax and urine to exit the body

Urine facts Amount is based on hydration and fluid intake (IV fluids) Bladder size and sensitivity vary Holding it in can lead to UTIs – May cause you to have to go more often than normal – Treated by antibiotics Holding it may enlarge the bladder You probably won’t do any real DAMAGE by holding it

Laboratory testing BUN – Blood urea nitrogen Creatinine clearance – Important test to assess the function of the kidney

Clinical procedures CT Scan – Useful in diagnosis of tumors, cysts, abcesses KUB – Shows the size and location of kidneys in relation to other organs in the abdom/pelv. Cavity Renal angiography – Helps diagnose areas of bleeding within a kidney RP – Retrograde pyelogram – Injection of contrast through catheter

Clinical procedures VCUG – Voiding cystourethrogram Ulrasonography – Use of high frequency sound waves – Size can be diagnosed Radiosotope scan – Injection of radioactive substance Size, shape, function

Dialysis HD – Hemodialysis Use of artificial kidney machine ; receives waste filled blood, filters it, returns the dialyzed blood to the patient’s body PD – Peritoneal dialysis Fluid through catheter, chemical reaction causes waste to pass out of bloodstream and into fluid, then fluid is drained out g g

Urinalysis Normal pH is – Above 7 = alkaline (bladder infection) – Below 7 = acidic Casts – Protein accumulation – Often composed of pus or fats Specific gravity – Measurement of waste, minerals and solids – Low may indicate kidney disease – High may indicate diabetes

Various substances Ketones-can lead to high levels of acid – Starvation or diabetes Albumin-serum protein – May indicate leakage of protein into blood Glucose – Usually indicates diabetes Pus – Infection or inflammation Blood – Bleeding in urinary tract Calcium – Rickets Viatmin D or calcium deficiency Lack of vitamin D makes it hard to maintain levels of calcium and phosphorus Softening or weakening of bones, usually in children