IgG4-related tubulointerstitial nephritis: renal capsule-like rim

The glomerulus and Bowman's capsule are two essential components of the nephron, which is the functional unit of the kidney. These microscopic structures play a critical role in the process of blood filtration to produce urine.
Glomerulus: Structure and Function
The glomerulus is a tiny, intricate network of capillaries located at the beginning of the nephron. It's enveloped by the Bowman's capsule and receives its blood supply from an afferent arteriole, which divides into numerous...

The kidneys are a pair of bean-shaped organs in the human body that play a critical role in maintaining overall health. They filter out waste products from the blood, regulate blood pressure, maintain electrolyte balance, and stimulate the production of red blood cells.
The kidneys are located in the retroperitoneal space on either side of the vertebral column, protected posteriorly by the 11th and 12th ribs. The right kidney sits slightly lower than the left owing to the presence of the liver...

Nephrotic Syndrome is a chronic kidney disorder defined by clinical findings such as severe proteinuria, hypoalbuminemia, hyperlipidemia, and edema. These symptoms result from damage to the glomeruli, the kidney’s filtering units, increasing their permeability to proteins.Definition and Meaning:Proteinuria, defined as the loss of more than 3.5 grams of protein per day in adults, is a crucial feature of nephrotic syndrome. This condition is often accompanied by edema, the accumulation of...

Acute kidney injury (AKI) causes are categorized into three primary categories based on the location of the injury: prerenal, intrarenal (or intrinsic), and postrenal causes. This classification guides clinical management and illustrates how different pathways can impair kidney function.Etiology and Pathophysiology of Acute Kidney Injury1. Prerenal causesEtiology: Prerenal Acute Kidney Injury, the most common type, occurs when reduced blood flow to the kidneys decreases filtration capacity...

The renal tubule is divided into three parts: the proximal convoluted tubule (PCT), the Loop of Henle (LOH), and the distal convoluted tubule (DCT).
Proximal Convoluted Tubule (PCT):
The PCT is the initial segment of the renal tubule, extending from the Bowman's capsule that encloses the glomerulus. Its convoluted structure and microvilli-lined cells increase the surface area for reabsorption. The PCT reabsorbs glucose, amino acids, sodium, and water from the filtrate, ensuring essential...

The filtration membrane in the renal system is a highly specialized structure essential for filtering blood. It consists of glomerular capillaries and podocytes, forming a selective barrier that permits the passage of water and small solutes while restricting most plasma proteins and blood cells.
Components of the Filtration Membrane
The filtration process involves three key layers: the glomerular endothelial cells, the basement membrane, and the podocyte-formed filtration slits.