Rat Urinary System

Examine your dissection specimen and locate the paired kidneys, which are embedded in fat on the dorsal body wall (Figure 9, 10). Note the fat, which remains around the kidneys. Locate the ureter, which is found exiting the kidney (along with the renal blood vessels) at a depression called the hilus (Figure 11). The ureter is the duct, which carries urine from its site of formation to the urinary bladder for storage. The urinary bladder is usually quite small and firm as it is empty and its muscles are contracted in these preserved specimens. The duct leading from the bladder to the exterior is the urethra. In the male, the urethra travels through the penis and is the passage for sperm during reproduction as well as the tract for urine at other times. In the female, the reproductive products do not exit through the urethra. It is also very difficult to find in the female.
Examine the demonstration of a kidney that has been cut in half with a median longitudinal section. You will notice that there may be large amounts of red and/or blue dye in some parts of the kidney; this is indicative of the highly vascularized nature of the kidneys. In addition, the kidney is not homogeneous; the outer portion is called the cortex and the inner region is called the medulla (Figure 11).
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Figure 9: Female rat urogenital system.
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Figure 10: Male rat urogenital system.
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Figure 11: Longitudinal section of human kidney.
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