Nephron Structure and Blood Supply

Overview

This lecture covers the structure and main parts of the nephron, the functional unit of the kidney, and introduces associated blood vessels.

The nephron is the kidney's functional unit, with about one million nephrons per kidney.
After age 45, approximately 1% of nephrons degenerate each year.
Main parts of the nephron: Bowman's capsule, proximal convoluted tubule (PCT), loop of Henle, distal convoluted tubule (DCT), and collecting duct.
Bowman's capsule receives filtered substances and opens into the PCT.
The PCT leads into the loop of Henle, which is U-shaped and has descending and ascending limbs.
The loop of Henle continues into the DCT, which connects to the collecting duct.
The collecting duct drains into minor calyces, then major calyces, pelvis, ureter, bladder, and finally urethra.

The glomerulus is a capillary network formed by the efferent arteriole branching from the renal artery.
Bowman's capsule plus the glomerulus is termed the Malpighian body.
The efferent arteriole forms peritubular capillaries around the renal tubule.
Long loops of Henle are surrounded by additional U-shaped capillaries called vasa recta; short loops may lack vasa recta.

Nephron — The structural and functional unit of the kidney.
Bowman's capsule — The double-walled structure that receives the filtrate from the glomerulus.
PCT (Proximal Convoluted Tubule) — The first twisted section after Bowman's capsule.
Loop of Henle — U-shaped segment of the nephron with descending and ascending limbs.
DCT (Distal Convoluted Tubule) — The twisted segment after the loop of Henle.
Collecting duct — The final channel where urine from several nephrons gathers.
Glomerulus — Ball of capillaries inside Bowman's capsule for filtration.
Malpighian body — Bowman's capsule and glomerulus together.
Peritubular capillaries — Capillary network around the renal tubules.
Vasa recta — U-shaped capillaries around the loop of Henle, present in nephrons with longer loops.