Bio Exam Practice Topic 13 Excretion in Humans

Front

What is excretion?

Back

Excretion is the biological process of removing waste products from the body. It is essential for maintaining homeostasis and involves organs such as the kidneys, liver, and skin.

Front

What are the main organs involved in human excretion?

Back

The main organs involved in human excretion are the kidneys, ureters, bladder, and urethra. The skin and lungs also play a role in excreting waste.

Front

What is the function of the kidneys?

Back

The kidneys filter blood to remove waste products and excess substances, producing urine. They also help regulate blood pressure, electrolyte balance, and acid-base balance.

Front

Define urine. What does it consist of?

Back

Urine is a liquid waste product excreted by the kidneys. It consists mainly of water, urea, creatinine, uric acid, and various ions.

Front

What is the role of the liver in excretion?

Back

The liver processes nutrients and detoxifies harmful substances. It converts ammonia, a toxic byproduct of protein metabolism, into urea, which is then excreted by the kidneys.

Front

Explain the process of filtration in the kidneys.

Back

Filtration in the kidneys occurs in the glomerulus, where blood is filtered under pressure. Water, ions, and small molecules pass into the Bowman's capsule, while larger molecules and blood cells remain in the bloodstream.

Front

What is reabsorption in the context of kidney function?

Back

Reabsorption is the process by which the kidneys reclaim water, ions, and nutrients from the filtrate back into the bloodstream, ensuring that essential substances are not lost.

Front

What is the difference between excretion and egestion?

Back

Excretion refers to the removal of metabolic waste from the body (e.g., urine), while egestion is the elimination of undigested food and waste (e.g., feces) from the digestive system.

Front

What is homeostasis, and how is it related to excretion?

Back

Homeostasis is the maintenance of a stable internal environment in the body. Excretion helps achieve homeostasis by regulating the levels of water, salts, and waste products.

Front

What are nephron units?

Back

Nephrons are the functional units of the kidneys, responsible for filtering blood and forming urine. Each kidney contains about a million nephrons.