Renal Anatomy Lab

Kidneys are retroperitoneal, located behind the peritoneum in the abdominal region.
Renal arteries branch off the abdominal aorta at the renal hilum.
Ureters connect the kidneys to the retroperitoneal urinary bladder.
Perirenal fat capsule surrounds the kidneys; loss of this fat can cause renal ptosis (kidney drooping).

The detrusor muscle is the smooth muscle layer in the bladder wall.
Ureters enter the bladder from underneath, filling it from the bottom up.
The trigone is a triangular region defined by the two ureteral openings and the urethral opening.
Females lack an internal urethral sphincter but have a thickened smooth muscle layer; both sexes have an external urethral sphincter (skeletal muscle).
Males possess both internal and external urethral sphincters. The internal sphincter prevents urine from entering the urethra during erection/ejaculation.
The male urethra is divided into the prostatic, membranous, and spongy urethra.
An enlarged prostate can interfere with urination by compressing the prostatic urethra.

Micturition requires detrusor muscle contraction and opening of both internal and external urethral sphincters (in males).
Females rely on a thickened smooth muscle portion instead of an internal sphincter.
The external urethral sphincter is under voluntary control via somatic motor nerves.
The micturition reflex involves sensory neurons detecting bladder wall stretch, sending signals to the spinal cord.
Increased parasympathetic and decreased sympathetic activity affect the detrusor muscle and internal urethral sphincter.
The pontine micturition center in the pons promotes urination, while the pontine storage center inhibits it.

The outer region is the cortex, and the inner region is the medulla, which contains renal pyramids.
The papilla is the bottom part of each pyramid where collecting ducts emerge.
Calyces (minor and major) collect urine; minor calyces merge into major calyces, which form the renal pelvis, leading to the ureter.

The renal artery branches into segmental arteries, then interlobar arteries (between pyramids), arcuate arteries (between cortex and medulla), and cortical radiate arteries (in the cortex).
Afferent arterioles lead to the glomeruli, then the efferent arterioles lead to peritubular capillaries or vasa recta.
Venous flow reverses the arterial order: cortical radiate veins, arcuate vein, interlobar vein, renal vein, and then to the inferior vena cava.

The renal corpuscle includes the glomerulus (capillary ball) and Bowman's capsule (glomerular capsule).
The nephron consists of the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.