Draw the excretory system and label its parts.

Explanation

Excretory system in human consists of a pair of kidneys, a pair of ureters, urinary bladder and urethra. Kidneys are reddish brown, bean shaped structures that lie in the lumbar region between the last thoracic and third lumber vertebra. The right kidney is slightly lower than the left kidney. Each kidney weighs about 120-170 grams. The outer layer of the kidney is covered by three layers of supportive tissues namely, renal fascia, perirenal fat capsule and fibrous capsule.
The longitudinal section of kidney shows an outer cortex, inner medulla and pelvis. The medulla is divided into a few conical tissue masses called medullary pyramids or renal pyramids. The part of cortex that extends in between the medullary pyramids is the renal columns of Bertini. The centre of the inner concave surface of the kidney has a notch called the renal hilum.
Through this ureter, blood vessels and nerves innervate. There is a broad funnel shaped space called the renal pelvis with projection called calyces. The walls of the calyces, pelvis and ureter have smooth muscles. The calyces collect the urine and empties into the ureter. It is stored in the urinary bladder temporarily. The urinary bladder opens into the urethra through which urine is expelled out.