Human body waste products and excretion may not be a pleasant topic of conversation. However, monitoring what comes out is a valuable tool, for instance you can assess your body’s response to what you take in or an abnormality can be a sign of a health issue. This health blurb covers basic information about waste and its excretion, including metabolic waste.
Human waste is any substance your body does not need to maintain homeostasis. Excretion is the process of removing these unwanted products through either the skin, urinary system, respiratory system or gastrointestinal system. The primary organs involved in waste removal are liver, kidneys, lungs, intestines and skin. Sometimes, human body produced waste is referred to as toxic because of the potential health effects caused insufficient removal.
Generally, human waste is produced during routine body functions, such as catabolism, metabolism and digestion. However, the meaning of waste is anything that’s unnecessary for homeostasis, so it could include other sources. For instance, your body likely contains a variety of environmental toxins that gain entry via air, water, food and skin contact, which are waste and need to removed as well. Another example is immune system destroyed pathogens and bacteria produced toxins are another form of waste your body needs to get rid of. However, this post primarily discusses the more common usage of human and metabolic waste.
Catabolism is the breaking down of large molecules into smaller ones for use by your body. By way of example, one molecule that is regularly catabolized and produces nitrogen based waste is protein. This waste product is in the form of ammonia, which can be very toxic. Fortunately your liver converts it to urea, which your body can tolerate in higher concentration. Once converted, urea is dumped back into the blood for collection by the kidneys and excreted in urine. Waste products released in the process of other types of catabolism are removed from your body through the skin, kidneys, lungs and intestines.
Metabolic waste is produced when a cell uses oxygen and nutrients (usually glucose and fats) to create energy. A waste product resulting from this activity that must be expelled to prevent your body from becoming to acidic is carbon dioxide, which is exhaled via your lungs. Water and heat are also produced, both of which can be used by your body to fulfill other requirements. However when they’re in excess, heat will be excreted through the skin (vasodilation of blood vessels) and water is discharged by way of the skin, urinary, respiratory or gastrointestinal systems.
Digestive waste is what remains after the digestion and absorption of food, coupled with waste contained in bile, particularly bilirubin from hemolysis. The path for excretion of these solids is through the colon for ultimate elimination out your anus.