Human Excretion and Kidney Physiology

The kidneys filter blood, removing waste products and excess substances to produce urine. Each kidney contains about a million nephrons that perform this filtration. The brain controls bodily functions, intestines digest food, and the nose is for breathing and smell.

The brain relies almost exclusively on glucose for its energy requirements, as it cannot use fatty acids or other fuels directly. Under normal conditions, glucose is the primary substrate for brain metabolism, though it can use ketone bodies during fasting.

Humans can live without a pancreas with insulin and enzyme replacement therapy. The pancreas produces insulin and digestive enzymes, both of which can be supplemented. Unlike essential organs like the heart or brain, pancreatic functions can be medically managed after removal.

The kidneys are the body's primary filtration system, removing waste products and excess substances from blood through millions of tiny filtering units called nephrons. Each kidney processes about 200 quarts of blood daily, producing about 2 quarts of waste fluid (urine). The kidneys also regulate blood pressure, electrolyte balance, and red blood cell production.

A urologist specializes in treating conditions of the urinary tract, including the bladder. The other specialists listed deal with different medical areas: skin, kidneys, and pregnancy.

A nephrologist is a kidney specialist who treats kidney diseases and disorders. The prefix 'nephr-' relates to kidneys. Other specialists listed treat joints, hormones, or skin.

Dialysis is an artificial process that performs the kidney's primary function of filtering waste products, excess salts, and fluids from the blood when kidneys fail. It is the definitive treatment for end-stage renal disease and acute kidney failure. The procedure has no therapeutic effect on heart weakness or brain diseases.

Nephritis is the inflammation of the kidneys, derived from the Greek word 'nephros' meaning kidney. This condition can affect kidney function and may be caused by infections, autoimmune diseases, or toxins. The kidneys filter blood and remove waste from the body.

Incontinence is indeed defined as the lack of voluntary control over excretory functions, which can affect bladder or bowel control. This is the standard medical definition.

Concentration of bicarbonate ions is not controlled by PTH. Its concentration depends on the buffering capacity of blood in the form of carbonate bicarbonate buffer

It is a sensory receptor mainly found in the hypothalamus.

Both kidneys receive an arterial supply directly from the aorta and the renal veins drain directly into the inferior vena cava.

Urea cycle disorders lead to buildup of ammonia. The mainstay of current treatment is to use substances such as sodium benzoate and sodium phenylacetate to complex with ammonia, forming water soluble compounds that can be excreted in the urine.

When hydrogen ions are secreted by the tubules, they can combine with NH₃ to form NH₄⁺ and so can be excreted as NH₄⁺_.