Definitions &Structures
This specialized 3-layered barrier retains albumin and plasma proteins while allowing water and small solutes to pass into Bowman's space
What is the Glomerular Filtration Barrier?
A canine patient presenting with dark reddish-brown urine following severe muscle trauma is diagnosed with pigmenturia. This specific muscle-derived pigment causes urine discoloration without intact red blood cells
What is Myoglobin (Myoglobinuria)?
This segment of the nephron reabsorbs 100% of filtered glucose and amino acids, as well as approximately 85% of filtered sodium and water
What is the Proximal Convoluted Tubule (PCT)?
These specialized columnar cells in the wall of the Distal Convoluted Tubule act as chemoreceptors sensing sodium () concentrations in filtrate
What are Macula Densa Cells?
This germ layer gives rise to the urinary bladder and urethral epithelial linings
What is Endoderm?
These intra-glomerular cells perform phagocytic, contractile, and structural support functions within the capillary tuft
What are Mesangial Cells?
A canine patient given high doses of an aminoglycoside antibiotic (gentamicin) develops acute renal damage. This tubular segment is the primary target for nephrotoxins due to its high metabolic activity and active uptake mechanisms
What is the Proximal Convoluted Tubule (PCT)?
This U-shaped tubular structure located exclusively in the medulla contains thick descending, thin, and thick ascending limb
What is the Loop of Henle (Nephron Loop)?
These modified smooth muscle cells located primarily in the wall of the afferent arteriole act as baroreceptors to release renin
What are Juxtaglomerular (JG) Cells?
This embryonic structure develops as an outgrowth of the mesonephric duct and gives rise to the ureter
What is the Metanephric Duct / Ureteric Bud?
This extensive apical membrane modification is found exclusively in the proximal convoluted tubule (PCT) and is absent in the distal convoluted tubule (DCT)
What is the Microvilli Brush Border?
A newborn foal presents with uroabdomen secondary to urinary bladder rupture following parturition. This anatomical feature of the dorsal bladder wall predisposes it to bulging and rupture under pressure
What is an external orientation of the circular smooth muscle layer on the dorsal surface?
This hormone acts on the Distal Convoluted Tubule (DCT) to promote sodium reabsorption and solute-free water retention back into circulation
What is Aldosterone?
Renin acts on this liver-derived plasma protein to produce Angiotensin I
What is Angiotensinogen?
In histology cross-sections, feline ureters display this unique muscular layer variation in their tunica mucosa
What is the complete absence of a lamina muscularis (propria-submucosa)?
Staining dark blue with Periodic Acid-Schiff (PAS), this extracellular structural component supports the base of renal tubular epithelial cells
What is the Basement Membrane (containing Type IV Collagen)?
A feline patient suffering from urethral obstruction has elevated blood urea nitrogen (BUN) and produces little to no urine. These two medical terms describe abnormally low urine volume and zero urine output, respectively
What are Oliguria and Anuria?
These two distinct epithelial cell types line the collecting ducts to manage electrolyte reabsorption and acid-base balance
What are Principal Cells and Intercalated Cells?
Beside regulating systemic blood pressure, the proximal convoluted tubule performs this crucial metabolic activation of a vitamin
What is the activation of Vitamin D (to active Calcitriol)?
This domestic species features mucous glands within the tunica submucosa of its urinary bladder
What is the Horse (Equine)?
These specialized fibroblast-like stromal cells in the renal interstitium produce a critical hormone required for erythropoiesis
What are Renin-Erythropoietin Producing (REP) Cells?
When treating a dog for severe acute renal failure, a histopathologist uses this special stain to evaluate the integrity of the glomerular basement membrane and brush borders
What is Periodic Acid-Schiff (PAS) Stain?
Secreted by hypothalamic neurons, this hormone inserts aquaporins into collecting duct principal cells to concentrate urine
What is Antidiuretic Hormone (ADH / Vasopressin)?
The overall biological cascade triggered by Juxtaglomerular Cell renin secretion leads to this net systemic outcome
What is increased blood pressure, increased sympathetic tone, and  retention?
This epithelium lines the urinary tract from the renal pelvis down through the proximal urethra, before transitioning to this epithelium in the distal urethra near the external orifice
What is Transitional Epithelium (Urothelium) transitioning to Stratified Squamous Epithelium?