The function unit of the kidney called

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, produce urine, which travels through the collecting ducts, minor/major calyces, to the renal pelvis and ureters.

Internal urethral sphincter (D): This is a smooth muscle sphincter located at the junction of the bladder and urethra. It is involuntary, controlled by the autonomic nervous system. Its role is to prevent urine leakage by keeping the urethra closed until micturition is initiated.Found at the bladder neck, just where the urethra begins.

Peritoneum (A): The peritoneum is the serous membrane lining the abdominal cavity. It covers the superior surface of the bladder when the bladder is full. Appears as the outermost layer draped over the top of the bladder in anatomical diagrams.

External urethral sphincter (E ): This is a skeletal muscle sphincter located further down the urethra. It is voluntary, controlled by the somatic nervous system. Its role is to allow conscious control over urination. Found in the urogenital diaphragm, surrounding the urethra outside the bladder.

A. Interlobar artery → Arcuate artery → Cortical radiate artery: These vessels represent the centrifugal branching of the renal arterial tree. Blood flows from the columns into the corticomedullary junction and then the cortex. This sequence correctly follows the standard anatomical pathway of oxygenated blood.

B. Arcuate artery → Cortical radiate artery → Afferent artery: This sequence accurately depicts the progression from the base of the pyramids into the cortical parenchyma. Blood moves through interlobular vessels before reaching the individual nephrons. It reflects the physiological direction of high-pressure renal perfusion.

C. Renal vein → Interlobar vein → Arcuate vein: This list incorrectly reverses the centripetal drainage of the renal venous system. Venous blood must flow from the arcuate veins into the interlobar veins to reach the renal vein. The sequence fails to follow anatomical drainage.

D. Renal artery → Segmental artery → Interlobar artery: This progression follows the primary macroscopic divisions of the renal artery after entering the hilum. Blood moves from the main trunk into segmental branches and between the pyramids. This correctly identifies the initial stages of intrarenal circulation.

E. Afferent arteriole → Glomerulus → Efferent arterioles: This represents the specialized portal system within the renal corpuscle where glomerular filtration occurs. Blood enters the capillary tuft and exits via a second resistance vessel. It accurately describes the microvascular pathway of the functional unit.