The urinary and reproductive systems are associated closely in frogs and are jointly referred to as the Urogenital system. It is primarily involved in assisting the frog in carrying out urine excretion and reproduction. The main excretory product of frogs is urea and hence frogs are ureotelic animals.
The excretory system is the same in both male and female frogs, however, the reproductive structures differ. The excretion in frogs is majorly carried out through kidneys (filters blood), ureters (transportation of urine from kidneys to bladder), cloaca (structure where eggs/sperm, urine and faeces leaves the body) and urinary bladder (stores urine).
In frogs, the sexes are separate hence they are dioecious. That is to say that male and female frogs can be distinguished/identified externally only during the season of breeding. This is a result of males developing a copulatory or nuptial pad on its first digit of the forelimb. This characteristic is not seen in female frogs. Additionally, males possess vocal sacs to produce comparatively louder sounds. Consequently, the male and female urogenital system of frogs are studied separately.
Let us look at the male and female urogenital system of frog:
Urogenital system of Frog – Males
The structures of the urogenital system of frogs in males are:
- Urinary bladder
- Bidders canal
- Vasa efferentia
Kidney – Kidneys are dark red and bean like structures, compact, occurring in a pair located posteriorly in the body cavity on both sides of the vertebral column. Each kidney consists of many functional and structural units – nephrons or uriniferous tubules.
Urinary Bladder – it is a thin walled structure present ventral to the rectum. It stores urine.
Ureter – the ureter or the urinogenital duct occur in pairs, projects from the kidney in the form of ureters in males.
Testis – These structures occur in a pair and are yellowish in appearance. These ovoid structures are located in the upper section of the kidneys by a double fold of the peritoneum known as mesorchium.
Bidder’s canal – It is a canal into which the vasa efferentia opens into the kidneys. Eventually this canal meets the ureter. This structure is responsible for passing urine, ova, water and sperm.
Vasa efferentia – It emerges from the testis and are 10-12 in number. They pass through mesorchium and move into the kidneys.
Cloaca – It is a small chamber mediating to pass urine, faeces and sperms to the outside. The ureter and urinary bladder opens into the cloaca.
Urogenital system of Frog – Females
The structures of the urogenital system of frogs in females are:
- Urinary bladder
The common structures in both male and female urogenital systems in frogs are kidneys, ureters and urinary bladder, their functionalities remain the same.
Ovary – It is a paired structure present close to kidneys. These yellow-colored structures are present on the outer side of the kidneys by a fold of peritoneum known as the mesovarium. Through the process of oogenesis, they produce ova. A mature female releases close to 2500-3000 ova at once.
Oviduct – These structures are paired and found on each side of the ovary. They are thin, large and coiled structures appearing white in color. These ducts open separately into the cloaca.
How is the blood supply to the Kidneys?
Blood supply to the kidneys is through the renal portal veins and renal arteries. Majorly blood constitutes urea as the excretory product. The renal artery branches in the kidney and redivides forming the afferent arteriole having a diameter larger than the efferent branch. The renal veins on the other side carries away the detoxified blood from the kidneys.
The renal portal veins branch into the kidney and these branches and the efferent arteriole unites forming a mesh of capillaries near the uriniferous tubules and ultimately together they form the renal venule.
Role of the Urogenital system
Mainly, this system excretes urea which is carried into the kidney by the blood and eventually is distilled and excreted out. The renal structures of this system hence remove urea from the body of the frog. The reproductive or genital structures of this system generate sex cells ready to be delivered out of the body for the process of external fertilization.
This was a brief on the urogenital system of the frog, different structures found in the male and female frogs, role and importance of this system. Alternatively, you may visit BYJU’S NEET to discover and learn more related information for NEET.