Kidney
Explanation:
The kidney is in the medial part of the body, located inferior to the lungs and posterior to the intestines.
The kidney is the most important excretory organs of vertebrate, which receives blood from the dorsal aorta through the right and left renal arteries and sends out blood through the right and left renal veins. The transverse section of the kidney shows an outer cortex, beneath which is the Medulla and beneath the Medulla, the hollow pelvis of the kidney.
The cortex and the Medulla consist of thousands of nephrons, which are the kidney's structural and functional units. Each nephron consists of a Bowman's capsule, also called renal corpuscle or malpighian corpuscle, with its network of blood capillaries called glomerulus within it. The remaining part of a nephron is a tubule consisting of three distinct portions, i.e., the proximal convoluted tubule, the U-shaped loop of Henle, and a distal convoluted tubule.
The tubule then leads into the pelvis of the kidney via the collecting tubules. The cortex contains only the renal corpuscle and the convoluted tubules, while the Medulla contains the loop of Henle and the collecting ducts. Ultrafiltration of the blood occurs in the Bowman's capsules, and glucose, amino acids, and large amounts of inorganic ions are reabsorbed at the proximal convoluted end from the glomerular filtrate. The sodium salt is actively transported out of the fluid as it passes through the loop of Henle, and finally, water is reabsorbed from the fluid at the distal convoluted tubule and the collecting ducts.
From here, the filtrate passes through the pelvis into the urinary bladder via the ureter. When the bladder becomes full, the urethral sphincter guarding the outlet relaxes so that urine flows out through the urethra.
Urine contains urea, water, and sodium chloride in addition to other compounds. In the presence of antidiuretic hormone, dilute urine is produced. Kidney stones are solid particles formed in the kidneys, which can block kidney tubules.
