Urinary System: The Urinogenital System

Urinogenital system comprises urinary system and reproductive system.

Urinary system – * The urinary system is the body’s waste removal system. The kidneys' main function is to process and remove wastes (created from cell metabolism) and excess ions from the blood, regulate blood volume and maintain electrolyte balance. The urinary system consists of paired kidneys and ureters. Kidneys – *Kidneys are metanephric and paired. *Each kidney is dark brown, flattened, three lobed structure (Fig. 20.25) and remain fitted into the dorsal

20.25). *Each testis is located in front of the top lobe of the kidneys. *The right testis is slightly smaller than the leftkidney. *Each testis remains attached kidney by a peritoneal fold called mesorchium. *The size of kidney varies according to breeding season. *During breeding season, each testis becomes enlarged in size. *Each testis is made up of a large number of coiled tubules called seminiferous tubules. *In between tubules, cluster of small cells are found called Leydig cells (Interstial cells). *These are endocrine cells which secretes male sex hormones. B) Vasa deferentia – *A narrow and convoluted duct arise from the inner broader side of each testis called vas deferens

Ovary – *There is only one ovary ie of left side (Fig. 20.26) which is situated near the anterior lobe of the left kidney. *It is attached to kidney by a peritoneal fold called mesovarium. *Although the right one is present embryologically, it regresses during development and is vestigial in the adult bird. *The right side being underdeveloped and non functional. *The ovary is large and irregular structure. *The size of the ovary increases greatly during breeding season and becomes decreased in the post breeding period. *The ovary when mature looks like a cluster of