Kidney ureter and urinary bladder
This specimen shows the parts of the urinary system, namely, the kidneys, the ureters and the urinary bladder.
The right kidney and the left kidney are a pair of bean-shaped, excretory organs situated in the posterior abdominal wall on either sides of the vertebral column. Both the kidneys present two poles (upper and lower), two borders (medial and lateral) and two surfaces (anterior and posterior). The upper poles of both the kidneys are close to the midline and are related to the suprarenal glands. The left suprarenal gland is seen in this specimen. Medially, the kidneys present a hilum, which allows the passage of Renal vein, Renal artery and Renal pelvis from anterior to posterior. The left renal artery can be seen in this specimen. The nephrons within the kidneys, purifies the blood and forms the urine. The urine formed is drained by the ureters into the urinary bladder. The renal calculi (kidney stones) can be lodged in the kidneys or in the ureters. The other structures seen in this specimen are the Inferior vena cava and the Abdominal aorta.
The right kidney is slightly lower than the left kidney due to the pressure exerted by the liver on the right side. Posteriorly it is related to only the 12th rib.
The left kidney is longer compared to the right kidney. Posteriorly, it is related to 11th and 12th ribs.
Left suprarenal gland:
The left suprarenal gland is semilunar in shape, whereas the right suprarenal gland is triangular in shape. Each gland possesses two functionally, developmentally and structurally distinct parts: an outer cortex and an inner medulla. The cortex secretes three types of steroid hormones, namely the mineralocorticoids, the glucocorticoids and the androgens. These hormones are mainly responsible for controlling the electrolyte and water balance. The medulla secretes the hormones such as the epinephrine and the nor-epinephrine.
Left renal artery:
The left renal artery is a branch of abdominal aorta. It passes through the hilum and supply the left kidney.
The renal veins (right and left) drain the venous blood from the kidneys into the inferior vena cava. The left renal vein receives the left gonadal vein and the left suprarenal vein.
The renal pelvis is the initial part of the ureters. Renal pelvis is formed by the coalescence of the major calyces within the kidneys and extends up to the lower poles of the kidneys. Thereafter, the renal pelvis continues as the ureters.
The ureters are a pair of tubes that convey urine from the kidney to the urinary bladder. They are 25cms long. Multiple arteries supply the ureters. Ureteric calculus can lead to ureteric colic (severe pain due to stones in ureters).
The urinary bladder is a muscular bag that temporarily stores urine. It is located in the lesser pelvis behind the pubic symphysis. An empty urinary bladder is tetrahedral in shape. The ureters open into the posterior aspect of the urinary bladder. The neck of the urinary bladder is directed downwards and becomes continuous with the urethra at the internal urethral orifice. In males, the prostate gland is situated onto the urethra and the neck of the urinary bladder. In case of benign prostatic hypertrophy, the median lobe of prostate enlarges producing an elevation within the urinary bladder known as uvula vesicae. This uvula vesicae obliterates the internal urethral orifice, thereby making the passage of urine more difficult.
Inferior vena cava:
The Inferior vena cava lies to the right of the midline and receives the renal veins (right and left).
The abdominal aorta lies to the right of the midline and gives rise to the renal arteries. The renal arteries supply the kidneys.