Question

Draw a well-labelled diagram of a human excretory system. Write the functions of
(a) Kidney
(b) Ureter
(c) Urinary bladder

Answer 1

Hint: 2 bean shaped structure found in vertebrates is kidney, ureter is present at each kidney which transport urine to the temporary reservoir for the urine i.e., urinary bladder.

Complete answer:

First of all, you should know about the human excretory system. The human excretory system consists of:
-Two kidney
-Two ureters
-One urinary bladder
-One urethra

Kidney:
-There are 2 kidneys which are bean-shaped structures found in the back on the left and right side of the spine below the ribs and behind the belly.
-It is mainly found in vertebrates.
-The kidney is divided into three regions i.e., outer layer is the renal cortex, inner layer is the renal medulla and the renal pelvis.
-Renal pelvis is responsible for carrying the urine from the kidney which is passed to the ureter.
-Nephron is called a functional unit of a kidney which functions to filter blood and expel waste products. There is a presence of millions of nephrons in each kidney.
Function of Kidney:
-It filters out the blood by removing nitrogenous waste and some other toxic substances from it.
-Kidney helps in the formation of urine.

Ureters:
It is a thin muscular tube which carries urine from the kidney and transfers to the bladder. There is a presence of one ureter in each kidney which means there are a total of two ureters present as there are two kidneys. Ureter comes out of each kidney as an extension of the renal pelvis.
Function of Ureter:
-Ureter tubes carry the urine from the kidney and transport it to the body's urinary bladder.

Urinary bladder:
Urinary bladder is a sac-like structure which is lined by a smooth muscle layer and it is a temporary reservoir for urine as the urine from the kidney is transported into the urinary bladder by ureter. It is located in the pelvic cavity and its shape varies with the amount of urine it contains.
Function of Urinary bladder:
-It is responsible for the storage of urine till the urine is excreted out from the body by urination.
-It allows us to accommodate up to 400-600 ml of urine in healthy adults.

Urethra:
It is a tube which arises from the urinary bladder as shown in the diagram. It is usually shorter in females while in males, it is longer. The opening of the urethra is guarded by a sphincter as shown in diagram. Sphincter controls exit of urine.
Function of Urethra:
-It functions as a common path for sperms and urine.
-Sphincter in urethra controls exit of urine.

Note: Kidney, Ureter and urinary bladder is a part of the excretory system where the kidney functions to filter out the blood and in the formation of urine and then the urine from the kidney passes to the urinary bladder through the ureter. Urinary bladder functions to store the urine till it is excreted out from the bladder.