Histopathology of the Urinary Tract and Kidney Flashcards
What are the components of the nephron?
The nephron is composed of the renal corpuscle and the renal tubule
What are the components of the renal corpuscle?
The renal corpuscle is composed of Bowman’s capsule, glomerulus, glomerular basement membrane (GBM), afferent arteriole, efferent arteriole, glomerular capillaries, mesangium, nuclei, and interstitium.
What are the characteristics of the Proximal Convoluted Tubules (PCT)?
The Proximal Convoluted Tubules (PCT) reabsorb approximately 65% of the glomerular filtrate. They are lined by simple cuboidal epithelium with tall microvilli (brush border) that increase the surface area by over 20-fold. The reason for this increased surface area is to enhance reabsorption.
What happens in the Distal Convoluted Tubules (DCT)?
In the Distal Convoluted Tubules (DCT), Na+ ions are reabsorbed from the tubular fluid, while one H+ or K+ ion is secreted in exchange.
What does the Renal Medulla consist of?
The Renal Medulla consists of closely packed tubules of two types: the loop of Henle and the collecting tubules and ducts. It also includes the vasa recta.
What is the function of the Loop of Henle?
The Loop of Henle is responsible for urine concentration via the counter-current mechanism. It has four parts: Thick descending limb, Thin descending limb, Thin ascending limb, and Thick ascending limb. The thick segments have simple cuboidal epithelium and are involved in active transport of various ions and molecules out of the lumen and into the interstitium. The thin segments have simple squamous epithelium and allow for free diffusion of water.
What is the function of the collecting duct and vasa recta?
The collecting ducts, formed by the merger of several collecting tubules, concentrate urine by passive reabsorption of water into the medullary interstitium. On the other hand, the vasa recta take up water from the medullary interstitium and return it to the general circulation.
What does the lower urinary tract include?
The lower urinary tract consists of the renal pelvis and calyces, ureters, bladder, and urethra. It is specialized for the storage and excretion of urine, with no further modification of the urine possible after it leaves the renal medulla. The urothelium or transitional epithelium lines the urinary tract.
What is Glomerulosclerosis?
Glomerulosclerosis refers to glomerular scarring, which is the end-stage progression of most kidney diseases. It is characterized by the formation of scar tissue within the glomeruli.
What is Urinary Outflow Obstruction?
Urinary outflow obstruction can occur suddenly or gradually and can be partial or complete, as well as unilateral or bilateral. In cases of significant obstruction, it leads to hydronephrosis, which is the dilation of the renal pelvis and calyces associated with progressive atrophy of the kidney.
What is Urolithiasis (Renal stones)?
Urolithiasis, also known as renal stones, can occur anywhere in the urinary tract. It is fairly common, with a higher incidence in males than females, and typically peaks between the ages of 20 and 30. The types of renal stones include calcium stones, triple stones, uric acid stones, and cystine stones. While the exact cause is often uncertain, the most important determinant is the supersaturation and precipitation of components that form the stones.
What is Hydronephrosis?
Hydronephrosis refers to the dilation of the renal pelvis and calyces, accompanied by atrophy of the kidney parenchyma. It is caused by obstruction to the outflow of urine.
What are Cystic Kidney Diseases?
Cystic kidney diseases are a heterogeneous group of conditions that are reasonably common. They are important because they are a common cause of Chronic Kidney Disease and can present diagnostic challenges for radiologists and pathologists, as they can be mistaken for malignancies
What are the types of cystic kidney diseases?
The types of cystic kidney diseases include simple cysts, adult (autosomal dominant) polycystic kidney disease (ADPKD), and childhood (autosomal recessive) polycystic kidney disease. ADPKD is caused by defective PKD-1 or PKD-2 genes and is characterized by the presence of large kidneys, weighing up to 4 kg, with functioning nephrons dispersed between the cysts microscopically. These conditions may also be associated with extrarenal anomalies.
What are the types of benign renal neoplasms?
The types of benign renal neoplasms include angiomyolipoma and oncocytoma.
