Morpho-functional Characteristics of the Kidneys and Urine Formation

These flashcards cover the macroscopic and microscopic anatomy of the kidneys, the components and functions of the nephron, the mechanism of urine formation, and basic urinalysis and related pathologies discussed in the lecture.

Urinary System Components

Consists of the kidneys, ureters, urinary bladder, and the urethra (sidik kanalı).

Retroperitoneal

The position of the kidneys in the posterior abdominal wall, behind the peritoneum.

Right Kidney Skeletotopia

Located between vertebrae $T12-L3$, positioned lower than the left due to the liver.

Left Kidney Skeletotopia

Located between vertebrae $T11-L2$.

Hilum Renale (Böyrək Qapısı)

The entry/exit point of the kidney containing the renal vein, renal artery, and renal pelvis (V.A.P. order).

Capsula fibrosa

The innermost fibrous capsule directly covering the kidney parenchyma.

Capsula adiposa

The fatty capsule of the kidney.

Cortex renalis (Qabıq)

The outer, lighter-colored layer of the kidney containing ~85% of nephrons, renal corpuscles, and convoluted tubules.

Medulla renalis (Beyin)

The inner, darker layer consisting of 15-20 renal pyramids (pyramides renales).

Papilla renalis

The apex of a renal pyramid that opens into the minor calyces via foramina papillaria.

Calyx-Pelvis System Flow

The path of urine exit: Papilla $\rightarrow$ Area Cribrosa $\rightarrow$ Minor Calyx $\rightarrow$ Major Calyx $\rightarrow$ Pelvis $\rightarrow$ Ureter.

Nephron

The functional unit of the kidney, with approximately 1.3 million nephrons per kidney.

Cortical Nephrons

Comprising 85% of all nephrons, they have short loops of Henle and corpuscles located in the outer cortex.

Juxtamedullary Nephrons

Comprising 15% of nephrons, they have long loops extending deep into the medulla and are essential for creating the osmotic gradient.

Renal Corpuscle

The filtration interface composed of the Glomerulus and Bowman's capsule.

Filtration Barrier

A biological sieve consisting of 1. Fenestrated Endothelium (stops blood cells), 2. Basal Lamina (stops proteins >69k Da), and 3. Podocytes with Filtration Slits.

Proximal Convoluted Tubule (PCT)

The 'workhorse' of the nephron; reabsorbs 67-80% of water and sodium, and 100% of glucose and amino acids.

Loop of Henle Descending Limb

The segment of the nephron loop that is permeable to water and concentrates the tubular fluid.

Loop of Henle Ascending Limb

The segment of the nephron loop that is impermeable to water and actively pumps out salt ($Na/Cl$).

Distal Convoluted Tubule (DCT)

Responsible for fine-tuning ion exchange ($Na^+/K^+$) and acid-base balance, controlled by Aldosterone.

Juxtaglomerular Apparatus (JGA)

A sensor complex consisting of the Macula Densa, Juxtaglomerular (granular) cells, and Extraglomerular mesangial cells.

Macula Densa

Specialized cells in the distal tubule that sense the concentration of $NaCl$ in the filtrate.

Juxtaglomerular Cells

Renin-secreting cells located in the wall of the afferent arteriole.

Collecting System

The final site for volume control where $ADH$ (Vasopressin) acts on Principal cells to open Aquaporin-2 channels.

Countercurrent Multiplier

The mechanism involving the Loop of Henle that establishes a high osmotic gradient in the renal medulla.

Vasa Recta

Highly permeable capillaries that act as countercurrent exchangers to preserve the medullary osmotic gradient.

Urea (Karbamid)

The most abundant nitrogenous waste product found in urine after water.

Adult Daily Urine Volume

Typically ranges between $1000-1800 ml$ per day, with an average of $1500 ml$.

Poliuriya

Excretion of an excessive volume of urine, defined as more than $3 L$ in 24 hours.

Oliquriya

Insufficient urine production, defined as less than $400 ml$ within 24 hours.

Anuriya

The complete absence of urine excretion.

Specific Gravity (Sıxlıq)

The chemical property of urine with a normal physiological range of $1.002-1.040$.

Membranous Nephropathy (MN)

An autoimmune kidney disease characterized by GBM thickening and severe proteinuria (e.g., $6700 mg/g$).

PLA2R1 and THSD7A

Primary antigens targeted by IgG4 antibodies in Primary Membranous Nephropathy.