Question 1

What is the role of the kidneys in the excretion process in humans?

Accepted Answer

The kidneys play a crucial role in the excretion process by filtering blood to remove waste products and excess substances, such as urea, water, and salts. These waste products are then excreted as urine. This process is vital for maintaining homeostasis by regulating the body's fluid balance and ensuring that harmful substances are eliminated efficiently.

Question 2

How does the human body regulate water balance through excretion?

Accepted Answer

The human body regulates water balance through a process called osmoregulation, primarily managed by the kidneys. The kidneys adjust the concentration of urine based on the body's hydration levels. When the body is dehydrated, the kidneys conserve water by producing concentrated urine. Conversely, when there is excess water, the kidneys excrete more diluted urine. This regulation is controlled by hormones such as antidiuretic hormone (ADH), which increases water reabsorption in the kidneys.

Question 3

What is the significance of urea in the excretion system of humans?

Accepted Answer

Urea is a significant waste product in the human excretion system, formed in the liver through the breakdown of amino acids. It is a less toxic form of nitrogenous waste compared to ammonia. The kidneys filter urea from the blood, and it is then excreted from the body in urine. This process is essential for removing excess nitrogen from the body, preventing the accumulation of toxic substances, and maintaining a stable internal environment.

Question 4

How do the lungs contribute to the excretion process in humans?

Accepted Answer

The lungs contribute to the excretion process by removing carbon dioxide, a waste product of cellular respiration. During breathing, carbon dioxide is transported from the blood to the lungs, where it is expelled from the body when we exhale. This process is vital for maintaining the acid-base balance in the body and ensuring that carbon dioxide levels do not become toxic.

Question 5

What is the role of the skin in the excretion of waste products?

Accepted Answer

The skin plays a role in excretion by eliminating waste products through sweat. Sweat glands in the skin produce sweat, which contains water, salts, and small amounts of urea. Sweating helps to regulate body temperature and remove excess salts and waste products from the body. Although the skin's role in excretion is minor compared to the kidneys, it is still an important part of the body's overall waste management system.

Excretion in Humans

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