ureters
urethra

bladder w/
  ureteric orifices
  internal sphincter
  external sphincter
  trigone

Excretory System 

 the kidney
gross anatomy:

  renal cortex
  renal medulla
  pyramids
  renal pelvis
  minor calyx
  major calyx
 
renal artery
renal vein

  trigone:
​   contains sensory receptors that detect                     the stretching of the bladder. 
  micturition reflex:
   when the bladder reaches a certain fullness,
   stretch receptors in the trigone send signals to       the brain, triggering the urge to urinate. 

        blood flow through nephron of kidney

nephron in lobe of kidney

 the nephron   
nephron w/
  afferent arteriole
  efferent arterioles
  bowman's capsule
  glomerulus
  proximal convoluted tubule
  distal convoluted tubule
  loop of the nephron (Henle)
  peritubular capillaries (vasa recta)
  collecting duct