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

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