Excretory System 



By Matthew Yankowitz


The function of the excretory system is the removal of wastes from the body.  The excretory system is made up of the kidneys, urinary bladder, ureters, and a urethra.  The excretory system is illustrated throughout this page using found diagrams and pictures taken during our dissection.


The pig has two kidneys, each located in the dorsal region of the pig’s abdominal cavity.  Their main functions are the maintenance of water and electrolyte balance, and the filtering of blood of wastes.  These wastes are in the form of urine, which is excreted by the kidneys to the bladder.




Human kidneys viewed from behind with spine removed

A pair of kidneys

A pair of kidneys

A cut kidney, with the visible medulla and cortex


One kidney, with a ureter attached

A cut kidney, with the visible medulla and cortex, and a ureter coming out the middle  

A cut kidney




 A cut kidney

A further dissected kidney

  A further dissected kidney 

The pig’s urinary bladder is an elastic, muscular sac which collects urine from the kidneys for excretion.  Its elasticity allows it to expand and contract.  When empty, the bladder is contracted, the muscle on its inside is folded.  When full, the muscle unfolds, allowing for its expansion.  It can be found in dorsal region of the pig’s abdominal cavity.


The ureters are tubes leading from the kidneys to the bladder.  The urethra directs urine from the bladder to outside the body.



The interior of bladder.

A bladder with attached arteries

A bladder without the arteries

An inside-out bladder

A urinary bladder

A half-open bladder, with stretchy muscle inside

A completely out-turned bladder





A stretchy, out-turned bladder










Class dissection pictures



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