Urinary System and Kidney Anatomy

Overview

This lecture covers the structures and regions of the urinary system, focusing on the macroscopic and microscopic anatomy of the kidney.

The main parts are two bean-shaped kidneys, located in the lower back.
Each kidney connects to a ureter, a tube that transports urine to the bladder.
The bladder stores urine until urination.
The urethra carries urine from the bladder out of the body.
Sphincters are circular muscles at the base of the bladder and urethra that involuntarily control urine release.

The cortex is the outer, lighter pink layer of the kidney.
The medulla is the inner region, featuring fan-shaped structures called pyramids.
The renal pelvis is the innermost region where urine collects before moving to the ureter.

The renal artery brings oxygen-rich, waste-filled blood into the kidney.
The renal vein carries filtered, deoxygenated blood away from the kidney.
The ureter exits the kidney to carry urine to the bladder.
The renal capsule is a protective membrane around the kidney.
Pyramids are groups of tubules in the medulla, with their pointed tips called papillae.
The calyx (calyxes/calyces) collects urine from each pyramid and drains into the renal pelvis.
The renal pelvis is a hollow chamber collecting urine before it moves to the ureter.

The nephron is the kidney’s functional and structural unit, responsible for filtration.
Each nephron consists of a network of tubules and is wrapped in capillaries.
Blood enters the nephron through the afferent arteriole and exits via the efferent arteriole.
The Malpighian (renal) corpuscle is made up of Bowman's capsule (cup-shaped) and the glomerulus (a dense capillary network).
The proximal convoluted tubule is the first, twisty tube close to the corpuscle.
The loop of Henle is a thin, U-shaped tube with descending and ascending limbs.
The distal convoluted tubule is a twisty tube farther from the corpuscle.
The collecting duct gathers urine from multiple nephrons and delivers it to the renal pelvis.

Kidney — Bean-shaped organ filtering blood and producing urine.
Ureter — Tube carrying urine from kidney to bladder.
Bladder — Muscular sac storing urine.
Urethra — Tube expelling urine from the body.
Sphincter — Circular muscle regulating urine flow.
Cortex — Outer kidney region.
Medulla — Inner kidney region with pyramids.
Renal pelvis — Central cavity collecting urine.
Renal artery — Brings blood to kidney.
Renal vein — Removes filtered blood from kidney.
Renal capsule — Outer protective kidney layer.
Pyramid — Fan-shaped medulla structure.
Papilla — Tip of a pyramid.
Calyx (Calyx/Calices) — Collects urine from papillae.
Nephron — Kidney's functional unit.
Afferent arteriole — Brings blood into nephron.
Efferent arteriole — Takes blood out of nephron.
Malpighian body (Renal corpuscle) — Includes Bowman's capsule and glomerulus.
Bowman's capsule — Cup-shaped structure collecting filtrate.
Glomerulus — Capillary network for filtration.
Proximal convoluted tubule — First twisty tube of nephron.
Loop of Henle — U-shaped tube, ascending and descending limbs.
Distal convoluted tubule — Farther twisty tube from corpuscle.
Collecting duct — Collects urine from nephrons.

Review diagrams of kidney and nephron structures.
Prepare for upcoming lessons on processes such as ultrafiltration and tubular secretion.