MSU 361 Renal System Structures

Functions of the Renal System Regulates water balance Regulates sodium, chloride, and potassium Produces hormones that control blood pressure Produces creatinine  Daily activity of muscles  Filtered by kidneys  Indicates level of kidney functions

Functions of the Renal System Excretes wastes (nitrogen) Breaks down proteins and amino acids Produces ammonia  Extremely toxic to tissues  Liver converts ammonia to urea (less toxic)  Combines with CO 2  Uric acid formed  Enzymes break down uric acid (Dalmatians produce less enzymes and don’t metabolize uric acid)  Special diet to limit uric acid production Removing waste products from blood and eliminating them as urine

Kidneys Renal artery and vein are in the center and supply 20-25% of blood Produce urine  2 reddish brown organs  Bean shaped and smooth  Located in the dorsal abdomen on either side of the spine Cows are only mammal with lobed kidneys

Function All of the blood in the body circulates through the kidney at some point The renal artery enters the kidney at the hilus  Its branches head toward the cortex The tubules of the nephron travel between the glomerulus and the medulla From the medulla toward the renal pelvis

Function (cont) The glomerulus is composed of a tuft of capillaries The blood is filtered through these capillaries as it enters the glomerulus Blood that is not sent along into the systemic circulation continues through to the rest of the nephron First section of tubules is the proximal collecting tubule

Kidneys Cortex- outer section Medulla- center section Renal pelvis- innermost section Nephron- unit that produces urine  Tube that filters blood into kidney

Ureters Center of each kidney; tube carries urine to the bladder  Smooth muscle  Pushes urine with peristalsis contractions

Urinary Bladder Hollow organ that expands and stretches Holds urine A 25 lb dog can hold 100 ml of urine in the bladder

Urethra Carries urine to outside of body Muscular tube that controls flow Males have longer and more narrow tubes than females  “Blocked” cats

Urethra Issues Female urethra  Higher incidence of urinary incontinence – urine leaks from bladder (uncontrolled)  Common in elderly spayed females  Common during sleep  Accidents in house  Respond to hormone supplement of normally produced estrogen

Urethra Issues Male Urethra  Longer and more narrow  Prone to urinary obstruction (bladder stones)  OS PENIS- bone where urethra passes; in dogs only  Exit of urethra is S-shaped; at the curve causes obstructions  Stone becomes lodged  Prevents urine from emptying  Surgical correction

Common Diseases and Conditions The process of eliminating waste from the body is critical to maintaining health and homeostasis Most urinary diseases have same symptoms:  PU/PD  Hematuria  Stranguria

Renal Diseases Most renal diseases are diagnosed with similar techniques:  Urinalysis  Chem Screen-  Especially watch Creatinine value

Urinary Incontinence Uncontrolled leaking of urine from the bladder Frequent in females Cystitis- inflammation of the urinary bladder  urinary tract infections  more prone to females  Signs:  Hematuria  Increased urination  Accidents  Dysuria

Urinary Blockage Uroliths – bladder stones that form within the urinary bladder and cause an obstruction Radiographs can help in diagnosis Surgical removal or a specialized diet help eliminate it Common in Dalmatians

Uroliths on X-ray

Feline Lower Urinary Tract Disease Cats get urinary blockage Build up of stones or crystals that form sandy sediment and block urethra Very painful, vocal, hard bladder, with time become dehydrated and weak Will die within hours due to kidney failure Male cats that are neutered are most common Obesity increases chances Diet control Catheter to flush out sediment PU surgery- perineal urethrostomy

Toxicity Ethylene glycol toxicity  Antifreeze toxicity  active ingredient in antifreeze that doesn’t metabolize and causes toxicity to the kidneys Ingested by animal due to good taste of product Induce vomiting with hydrogen peroxide or give activated charcoal About 80% of animals die Fluid therapy for renal failure  Acute- sudden onset  Chronic- long term

Renal Failure Chronic  Long term onset More common with senior pets Increased thirst, poor appetite, weight loss, loss of urine control, v/d Increased BUN, creatinine and phosphorus levels with anemia Diet control and fluid therapy; reduced protein

Renal Failure Acute  Short term onset Lyme Disease Toxin Dehydration **Some cases of acute failure can be reversed with supportive care

Review of the Structures  A pair of kidneys  Organ in which urine is formed  ren/o and nephr/o A pair of ureters  thick walled tubes that carry urine from the kidneys to the urinary bladder A single urinary bladder  hollow muscular organ that holds urine  cyst/o A single urethra  tube extending from the urinary bladder to the outside of the body  urethr/o