Introduction to the Urinary System, Renal Disease and Terminology

M.7R, W.1, L.1

List the component parts of the urinary system and their functions

Paired Kidneys

• filters blood plasma + forms urine

• endocrine function

Paired Ureters

• conduits; passageways that move urine down to bladder

Urinary Bladder

• storage of urine

• final composition of urine

Urethra

• urine passes to exterior during micturition

How many liters of blood pass through the kidneys per day?

How many liters of this are filtered by the kidneys?

How many liters of urine is produced per day?

• 1000-2000 liters blood/day pass through kidneys

• 200-300 liters filtered by kidney

• 1-2 liters urine/day produced

Describe the location of the kidneys (near what vertebrae, positioning in dogs and cats, etc)

• ventral to lumbar vertebrae

• asymmetrical positioning

  • Dogs

    • L1-3 right kidney

    • L2-4 left kidney

  • L5 feline (left kidney)

• retroperitoneal

• right kidney less mobile than left

  • (both mobile in cats)

Describe the location of the ureters, bladder (neck) and urethra

Ureters

• leave renal hilus & penetrate neck of bladder just cranial to pelvic inlet

Bladder (neck)

• anchored in pelvic inlet

Urethra

• enters vestibule of vagina or covered by penis

• associated with reproductive tracts (urogenital system)

Describe anatomically how the ureter travels from kidney to bladder

ureter travels caudally and ventrally within the broad ligament to penetrate the bladder at the neck

Describe the positions of the kidney, ovaries, and uterus in an intact female

• each kidney in close proximity to ovary

• uterus sits dorsal to bladder and ventral to colon/rectum

what are the testis located within?

scrotal sac

Describe how the ductus deferens/vas deferens travels in relationship to urinary organs

• ductus deferens travels from the testes

  • passes through inguinal canal into abdominal cavity, dorsal to ureter

    • and terminates in urethra at same point as prostate

What does the urethra serve as a conduit for and what structure does it continue into and where does it terminate?

• dual function as a conduit for both urine and sperm

• urethra continues into penis and terminates at prepuce

Describe the topography of the right kidney in the bitch (dorsal surface, cranial pole, caudal pole, medial surface, lateral, and ventral surface)

• Dorsal Surface: L1-L3

• Cranial Pole: Adrenal gland; Liver (fossa)

• Caudal Pole: Ovary

• Medial Surface: Caudal Vena Cava

• Lateral: Last rib

• Ventral Surface: Desc. duodenum, R. lobe pancreas, Asc. colon, and Cecum

Describe the topography of the left kidney in the bitch (dorsal surface, cranial pole, caudal pole, medial surface, lateral, and ventral surface)

• Dorsal Surface: L2-L4(5)

• Cranial Pole: Adrenal gland; spleen

• Medial Surface: Aorta

• Lateral: Abdominal wall

• Ventral Surface: Desc. colon, Small Intestines

Define AZOTEMIA

increase in nitrogenous waste in blood (urea & creatinine)

Define UREMIA and list the clinical signs

• clinical syndrome resulting from severe loss of kidney function

• Clinical signs:

  • weight loss, nausea, some vomiting

Define ANURIA

complete lack of urine production

• clinical emergency

Define POLYURIA

abnormally large volume of urine production

Define HEMATURIA

presence of blood in the urine

Define PIGMENTURIA

presence of pigment in the urine (other than blood)

Define PROTEINURIA

presence of an abnormal amount of protein in the urine

Define POLLAKIURIA. What species and sex can you mostly see this in

abnormally frequent passage of small volumes of urine

• feeling like bladder is full but only passing a little urine

• see in cats; mostly female

Define DYSURIA. What other clinical sign can you go hand in hand with this?

• difficult and/or painful passage of urine

• can go hand in hand w/ POLLAKIURIA

Define STRANGURIA

slow and painful passage of urine

Define URINARY INCONTINENCE

uncontrolled urination

Define INAPPROPRIATE URINATION

urination in inappropriate locations

List ways in which renal disease may present and which renal disease they are a presentation of

• PU/PD

  • CKD (Chronic Kidney Disease)

• Inappetence

  • Acute Kidney Injury (AKI)

• Weight loss

  • CKD

• Depression

  • AKI/CKD

• Vomiting/Nausea/Diarrhea

  • AKI/CKD

• Ascites/SQ edema

  • protein losing nephropathy (PLN)

• Hematuria

  • urolithiasis (stones), tumors, trauma

• Pain

  • pyelonephritis

• Abdominal Mass

  • tumors

List ways in which lower urinary tract disease may present and what disease they are a sign of

• Dysuria / Pollakiuria / Stranguria

  • bacterial cystitis, feline idiopathic cystitis (FIC)

• Hematuria

  • cystitis, tumors

• Urinary Retention

  • urolithiasis, tumors

• Urinary Incontinence

  • urethral sphincter mechanism incontinence (USMI), ectopic ureters

List some basic blood diagnostic tests used to detect urinary tract disease

• urea, creatinine, PCV, total solids, albumin, electrolytes, cholesterol

• SDMA (renal biomarker; assesses glomerular filtration rate)

List some basic urine diagnostic tests used to detect urinary tract disease

• urine dipstick

• urine specific gravity (USG)

• urine sediment analysis

• culture and sensitivity

List some basic diagnostic imaging tests used to detect urinary tract disease

• plain & contrast-enhanced radiographs

• ultrasound

• cytoscopy

  • less commonly performed

List methods for collecting a urine sample (3)

Free Flow

• normal micturition / manual expression

• non-invasive but time-consuming, sample contaminated

Urethral Catheterization

• difficult in females

• can introduce infection

• sample may be contaminated

Cystocentesis

• “blind” or ultrasound guided

• GOLD STANDARD METHOD

• more invasive

What tool is used to measure urine concentration (specific gravity)

refractometer

List the specific gravity of plasma

1.008 to 1.012

List the relative terminology used to describe the concentration of urine relative to plasma and the corresponding USG, and define the term

• Hyposthenuria: 1.000 to 1.007

  • urine more DILUTE than plasma

• Isosthenuria: 1.008 to 1.012

  • SAME concentration as plasma

• Hypersthenuria: 1.013 to 1.030

  • MORE concentrated urine than plasma

    • body conserves water by producing more concentrated urine

List the USG for minimally concentrated and well concentrated urine

Minimally concentrated urine: 1.013 to 1.030

Well concentrated urine: 1.030 to 1.055