Human Excretory System

Urea is the major end product of nitrogen metabolism in humans and mammals. Ammonia, the product of oxidative deamination reactions, is toxic in even small amounts, and must be removed from the body. The urea cycle or the ornithine cycle describes the conversion reactions of ammonia into urea. Since these reactions occur in the liver, the urea is then transported to the kidneys, where it is excreted.

Keratin is an extremely strong protein, which is a major component in skin, hair, nails, hooves, horns and teeth. The amino acids which combine to form keratin have several unique properties, and depending on the levels of the various amino acids, keratin can be inflexible and hard, like hooves, or soft, as is the case with skin.

Urea or carbamide is an organic compound. Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. It is solid, colourless and odourless, and ammonia is converted into urea by the liver.

The main excretory organ in man, are the kidneys. They excrete urine. The right kidney is lower than the left because of the presence of liver, in the abdominal cavity.

Gout is a medical condition, usually characterized by recurrent attacks, of acute inflammatory arthritis—a red, tender, hot, swollen joint. The metatarsal-phalangeal joint at the base of the big toe, is most commonly affected.

Most urinary tract infections (UTIs) are caused by Gram negative bacteria, such as, E. coli. If there is an obstruction of the urethra, catheterization may be needed, but as a general rule, catheterization in cases of UTI is contraindicated, because it can actually introduce pathogens, and make the infection worse. Women tend to acquire more urethral and bladder infections than men, because the opening of the urethra, is closer to the anus.

The glomerulus lining is such that it only allows small molecules to filter through, like glucose, plasma, ions like sodium and potassium, urea, etc. The larger molecules, like blood cells and protein, cannot pass through the glomerulus. Thus protein is not present in urine.

The excretory organ of cockroach is the malpighian tubules. It is found at the junction of the midgut and hind gut and are about 150 in number. They are fine, yellow coloured and branched threads, present in bundles. They lie freely in the haemolymph. It excretes uric acid.

Gout is a disorder in which humans start to accumulate, more than the usual amount of uric acid, caused by either the body manufacturing excess uric acid, or the kidneys not excreting enough of it, and since it's not water-soluble, it gets stored in the body, frequently in toe joints, causing pain and deformation of the joints involved, as well as, the formation of kidney stones.

The human spleen is an organ, that creates lymphocytes for the destruction and recycling, of old red-blood cells. The spleen is also a blood reservoir. It supplies the body with blood in emergencies, such as, a bad cut. The spleen does not help in excretion.

Anthrax is an acute disease, caused by the bacterium, Bacillus anthracis. Most forms of the disease are lethal, and it affects both humans and other animals. There are effective vaccines against anthrax, and some forms of the disease respond well, to antibiotic treatment. A diuretic may not be effective in anthrax.

The process by which, the water content and the ion concentration is regulated and kept constant, in the cells is known as osmoregulation. Kidneys perform both excretion and osmoregulation.

The final passageway for the flow of urine, is the urethra, a thin-walled tube that conveys urine, from the floor of the urinary bladder, to the outside. The opening to the outside is the external urethral orifice. The mucosal lining of the urethra is transitional epithelium. The wall also contains smooth muscle fibers, and is supported by connective tissue.

The urinary bladder is a temporary storage reservoir for urine. It is located in the pelvic cavity, posterior to the symphysis pubis, and below the parietal peritoneum. The size and shape of the urinary bladder, varies with the amount of urine it contains, and with pressure it receives from surrounding organs.

The gallbladder is a small pear-shaped organ, that stores and concentrates bile. The gallbladder is connected to the liver by the hepatic duct. It is approximately 3 to 4 inches (7.6 to 10.2 cm) long and about 1 inch (2.5 cm) wide. The function of the gallbladder, is to store bile and concentrate.

Each ureter is a small tube, about 25 cm long, that carries urine from the renal pelvis, to the urinary bladder. It descends from the renal pelvis, along the posterior abdominal wall, behind the parietal peritoneum, and enters the urinary bladder, on the posterior inferior surface.

There is a triangular area, called the trigone, formed by three openings in the floor of the urinary bladder. Two of the openings are from the ureters and form the base of the trigone. Small flaps of mucosa cover these openings, and act as valves, that allow urine to enter the bladder, but prevent it from backing up, from the bladder into the ureters. The third opening, at the apex of the trigone, is the opening into the urethra. A band of the detrusor muscle encircles this opening, to form the internal urethral sphincter.

Rice is a non diuretic substance. It does not help to increase urination.

It is the type of excretion, in which ammonia is the main nitrogenous waste material. Such animals are called ammonotetic. It is found in aquatic animal groups like, sponges, coelentrates, crustaceans, echinoderms, bony fish, tadpole larvae and salamander.

Urea is the major end product of nitrogen metabolism, in humans and mammals. Ammonia, the product of oxidative deamination reactions, is toxic in even small amounts, and must be removed from the body. The urea cycle or the ornithine cycle, describes the conversion reactions of ammonia into urea. Since these reactions occur in the liver, the urea is then transported to the kidneys, where it is excreted.

It is a large double walled cup. It lies in the renal cortex. It contains a tuft of capillaries called glomerulus and the outer wall is continuous, with the rest of the nephron. The space between the two walls of the Bowman's capsule is continuous, with the lumen of the next part of the nephron. The bowman's capsule and the glomerulus together constitutes the renal corpuscle or malpighian body.

Cfreatinine is not a nitrogenous waste in any of the above process.

Malphigian body contains a tuft of capillaries, called glomerulus. The bowman's capsule and the glomerulus together constitutes the renal corpuscle or malpighian body.

It works on the principle of dialysis, which is the diffusion of small solute molecules, through a semipermeable membrane. The haemodialyzer consists of a cellophane tube suspended in a salt - water solution of the same composition, as the normal blood plasma, but without any urea present in it.

The spleen is an organ found in virtually all vertebrate animals,  with important roles in regard, to red blood cells and the immune system.