HyperreninemiaRENblood plasma renin
Renin's primary function is therefore to eventually cause an increase in blood pressure, leading to restoration of perfusion pressure in the kidneys. Renin is secreted from juxtaglomerular kidney cells, which sense changes in renal perfusion pressure, via stretch receptors in the vascular walls. The juxtaglomerular cells are also stimulated to release renin by signaling from the macula densa. The macula densa senses changes in sodium delivery to the distal tubule, and responds to a drop in tubular sodium load by stimulating renin release in the juxtaglomerular cells. Together, the macula densa and juxtaglomerular cells comprise the juxtaglomerular complex.


kidney infectionpyelitisurosepsis
The kidney parenchyma presents in the interstitium abscesses (suppurative necrosis), consisting in purulent exudate (pus): neutrophils, fibrin, cell debris and central germ colonies (hematoxylinophils). Tubules are damaged by exudate and may contain neutrophil casts. In the early stages, the glomerulus and vessels are normal. Gross pathology often reveals pathognomonic radiations of bleeding and suppuration through the renal pelvis to the renal cortex. Chronic pyelonephritis implies recurrent kidney infections and can result in scarring of the renal parenchyma and impaired function, especially in the setting of obstruction.

Kidney cancer

renal cancerkidneyrenal
The most common type of kidney malignancy is renal cell carcinoma, which is thought to originate from cells in the proximal convoluted tubule of the nephron. Another type of kidney cancer although less common, is transitional cell cancer (TCC) or urothelial carcinoma of the renal pelvis. The renal pelvis is the part of the kidney that collects urine and drains it into a tube called the ureter. The cells that line the renal pelvis are called transitional cells, and are also sometimes called urothelial cells. The transitional/urothelial cells in the renal pelvis are the same type of cells that line the ureter and bladder.

Renal cyst

cystkidney cystrenal
A renal cyst is a fluid collection in or on the kidney. There are several types based on the Bosniak classification. The majority are benign, simple cysts that can be monitored and not intervened upon. However, some are cancerous or are suspicious for cancer and are commonly removed in a surgical procedure called nephrectomy. Numerous renal cysts are seen in the cystic kidney diseases, which include polycystic kidney disease and medullary sponge kidney. Renal cysts are classified by malignant risk using the Bosniak Classification System. The system was created by Dr. Morton Bosniak, a faculty member at the New York University Langone Medical Center in New York City.


uretersureteralureteropelvic junction
Those vessels closer to the kidney drain into renal collecting vessels; into the lateral aortic nodes near the gonadal vessels. In the lower ureter, lymph may drain into the common iliac lymph nodes, or lower down in the pelvis to the common, external, or internal iliac lymph nodes. The ureters are richly supplied by nerves that form a network of nerves, the ureteric plexus that lies in the adventitia of the ureters.


partial nephrectomynephroureterectomybilateral nephrectomy
He proved that one healthy kidney can be sufficient for urine excretion in humans. There are various indications for this procedure, including renal cell carcinoma, a non-functioning kidney (which may cause high blood pressure) and a congenitally small kidney (in which the kidney is swelling, causing it to press on nerves which can cause pain in unrelated areas such as the back). Nephrectomy for renal cell carcinoma is rapidly being modified to allow partial removal of the kidney. Nephrectomy is also performed for the purpose of living donor kidney transplantation.

Acid–base homeostasis

acid-base balanceacid-base homeostasisphysiological pH
*The third line of defence is the renal system, which can add or remove bicarbonate ions to or from the ECF. The bicarbonate is derived from metabolic carbon dioxide which is enzymatically converted to carbonic acid in the renal tubular cells. The carbonic acid spontaneously dissociates into hydrogen ions and bicarbonate ions. When the pH in the ECF tends to fall (i.e. become more acidic) the hydrogen ions are excreted into the urine, while the bicarbonate ions are secreted into the blood plasma, causing the plasma pH to rise (correcting the initial fall).


Raised hydrostatic pressure often reflects retention of water and sodium by the kidneys.

Pleural effusion

pleuraleffusionpleural effusions
Nephrotic syndrome. Acute atelectasis. Myxedema. Peritoneal dialysis. Meigs' syndrome. Obstructive uropathy. End-stage kidney disease. Red blood cell counts are elevated in cases of bloody effusions (for example after heart surgery or hemothorax from incomplete evacuation of blood). Amylase levels are elevated in cases of esophageal rupture, pancreatic pleural effusion, or cancer. Glucose is decreased with cancer, bacterial infections, or rheumatoid pleuritis. pH is low in empyema (

Organ (anatomy)

Excretory system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine. Lymphatic system: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the Immune system: defending against disease-causing agents with leukocytes, tonsils, adenoids, thymus and spleen. Integumentary system: skin, hair and nails of mammals. Also scales of fish, reptiles, and birds, and feathers of birds. Muscular system: movement with muscles. Nervous system: collecting, transferring and processing information with brain, spinal cord and nerves.


Lipiduria is most frequently observed in nephrotic syndrome where it is passed as lipoproteins along with other proteins. It has also been reported as a sign following fat embolism. When lipiduria occurs, epithelial cells or macrophages contain endogenous fats. When filled with numerous fat droplets, such cells are called oval fat bodies. Oval fat bodies exhibit a "Maltese cross" configuration under polarized light microscopy. The Maltese cross appearance occurs because of its liquid-crystalline structure giving it a double refraction (birefringence). * Urostealith

Renal fascia

Gerota's fasciaGerota CapsuleGerota's capsule
The renal fascia or Gerota's fascia is a layer of connective tissue encapsulating the kidneys and the adrenal glands. The renal fascia separates the adipose capsule of kidney from the overlying pararenal fat. The deeper layers below the renal fascia are, in order, the adipose capsule (or perirenal fat), the renal capsule and finally the parenchyma of the renal cortex. The spaces about the kidney are typically divided into three compartments: the perinephric space and the anterior and posterior pararenal spaces. The anterior fascia and posterior fascia fuse laterally to form the lateroconal fascia which fuses with the transverse fascia.

Renal capsule

fibrous tissue capsule surrounding the kidneyInferior renal capsulekidney capsule
From the inner part of the kidney to outside the kidney, the positioning of the capsule is: Sometimes the adipose capsule of the kidney also known as the perirenal fat, is regarded as a part of the renal capsule. * 1) renal medulla. 2) renal cortex. 3) renal capsule. 4) adipose capsule of kidney (or perirenal fat, or perinephric fat). 5) renal fascia. 6) pararenal fat. 7) peritoneum (anteriorly), and transverse fascia (posteriorly). Renal medulla. Renal pyramid. Renal artery. Renal vein.

Renal cortex

kidney cortexcortexcortical
The renal cortex is the outer portion of the kidney between the renal capsule and the renal medulla. In the adult, it forms a continuous smooth outer zone with a number of projections (cortical columns) that extend down between the pyramids. It contains the renal corpuscles and the renal tubules except for parts of the loop of Henle which descend into the renal medulla. It also contains blood vessels and cortical collecting ducts. The renal cortex is the part of the kidney where ultrafiltration occurs. Erythropoietin is produced in the renal cortex. Contains afferent arterioles * - "Posterior Abdominal Wall: Internal Structure of a Kidney"

Renal corpuscle

vascular poleMalpighian BodiesMalpighian corpuscles
A renal corpuscle is the blood-filtering component of the nephron of the kidney. It consists of a glomerulus - a tuft of capillaries composed of endothelial cells, and a glomerular capsule known as Bowman's capsule. The renal corpuscle is composed of two structures, the glomerulus and the Bowman's capsule. The glomerulus is a small tuft of capillaries containing two cell types. Endothelial cells, which have large fenestrae, are not covered by diaphragms. Mesangial cells are modified smooth muscle cells that lie between the capillaries. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and cytokines.

Renal lobe

renal lobes
The renal lobe is a portion of a kidney consisting of a renal pyramid and the renal cortex above it. In humans, on average there are 7 to 18 renal lobes. It is visible without a microscope, though it is easier to see in humans than in other animals. It is composed of many renal lobules, which are not visible without a microscope. * Renal capsule. Renal medulla.

Renal pelvis

pyelo-kidney pelvispelvic
The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. In humans, the renal pelvis is the point where the two or three major calyces join together. It has a mucous membrane and is covered with transitional epithelium and an underlying lamina propria of loose-to-dense connective tissue. The renal pelvis functions as a funnel for urine flowing to the ureter. The renal pelvis is the location of several kinds of kidney cancer and is affected by infection in pyelonephritis. The renal pelvis is the location of several kinds of kidney cancer and is affected by infection in pyelonephritis.

Interlobular arteries

interlobular arteryinterlobularinterlobate
Distally, efferent arterioles branch out to form dense plexuses (i.e., capillary beds) around their adjacent renal tubules. For cortical nephrons, a single network of capillaries, known as the peritubular capillaries, surrounds the entire renal tubule, whereas for juxtamedullary nephrons, the peritubular capillaries surround only the proximal and distal convoluted tubules, while another network branching from the efferent arteriole, known as the straight arterioles of kidney, surrounds the nephron loop (of Henle). * * - "Urinary System: kidney, H&E, interlobular artery and vein"

Renal calyx

minor calyxrenal calycescalyces
A "staghorn calculus" is a kidney stone that may extend into the renal calyces. A renal diverticulum is diverticulum of renal calyces. * Diagram at Renal medulla. Renal pyramids. - "Posterior Abdominal Wall: Internal Structure of a Kidney". - "Posterior Abdominal Wall: Internal Structure of a Kidney". - "Urinary System: neonatal kidney". Diagram at


dextroseD-glucose D -glucose
Nerve cells, cells of the renal medulla and erythrocytes depend on glucose for their energy production. In adult humans, there are about 18 g of glucose, of which about 4 g are present in the blood. Approximately 180 to 220 g of glucose are produced in the liver of an adult in 24 hours. Many of the long-term complications of diabetes (e.g., blindness, kidney failure, and peripheral neuropathy) are probably due to the glycation of proteins or lipids. In contrast, enzyme-regulated addition of sugars to protein is called glycosylation and is essential for the function of many proteins. Ingested glucose initially binds to the receptor for sweet taste on the tongue in humans.

Uric acid

urateuricblood uric acid
In humans, about 70% of daily uric acid disposal occurs via the kidneys, and in 5–25% of humans, impaired renal (kidney) excretion leads to hyperuricemia. Normal excretion of uric acid in the urine is 250 to 750 mg per day (concentration of 250 to 750 mg/L if one litre of urine is produced per day — higher than the solubility of uric acid because it is in the form of dissolved acid urates). Dogs. The Dalmatian dog has a genetic defect in uric acid uptake by the liver and kidneys, resulting in decreased conversion to allantoin, so this breed excretes uric acid, and not allantoin, in the urine. Birds and reptiles.

Abdominal cavity

abdominalabdomenabdominal (peritoneal) cavity
Organs of the abdominal cavity include the stomach, liver, gallbladder, spleen, pancreas, small intestine, kidneys, large intestine, and adrenal glands. The abdominal cavity is lined with a protective membrane termed the peritoneum. The inside wall is covered by the parietal peritoneum. The kidneys are located in the abdominal cavity behind the peritoneum, in the retroperitoneum. The viscera are also covered by visceral peritoneum. Between the visceral and parietal peritoneum is the peritoneal cavity, which is a potential space. It contains serous fluid that allows motion. This motion is apparent of the gastrointestinal tract.


ascitic fluidBulging flanksChylous ascites
Nephrotic syndrome. Hereditary angioedema. Meigs syndrome. Vasculitis. Hypothyroidism. Renal dialysis. Peritoneum mesothelioma. Abdominal tuberculosis. Mastocytosis. Grade 1: mild, only visible on ultrasound and CT. Grade 2: detectable with flank bulging and shifting dullness. Grade 3: directly visible, confirmed with the fluid wave/thrill test.

Proximal tubule

proximal convoluted tubuleproximal renal tubuleproximal tubular
Proximal tubular epithelial cells (PTECs) have a pivotal role in kidney disease. Two mammalian cell lines are commonly used as models of the proximal tubule: porcine LLC-PK1 cells and marsupial OK cells. Most renal cell carcinoma, the most common form of kidney cancer, arises from the convoluted tubules. Acute tubular necrosis occurs when PTECs are directly damaged by toxins such as antibiotics (e.g., gentamicin), pigments (e.g., myoglobin) and sepsis (e.g., mediated by lipopolysaccharide from gram-negative bacteria).