Explanation

• The total surface area of the respiratory surface in humans is about 20 times the size of the body.
• The human respiratory surface is formed by millions of tiny air sacs called alveoli in the lungs.
• Alveoli provide a large surface area for the exchange of oxygen and carbon dioxide between the air and blood.

Last verified on 28-10-2026

Explanation

• Bronchitis is the inflammation of the bronchial tubes, which carry air to and from the lungs.
• It commonly causes coughing, mucus production, chest discomfort, and sometimes shortness of breath.
• Bronchitis may be acute, often caused by viruses, or chronic, commonly associated with long-term exposure to irritants such as cigarette smoke.

Last verified on 28-10-2026

Explanation

• The kidneys are the main organs responsible for removing uric acid from the blood through urine.
• Approximately two-thirds (about 70%) of uric acid is excreted by the kidneys, while much of the remainder is eliminated through the intestines.
• Uric acid is produced during the breakdown of purines, which are found in body cells and certain foods.

Last verified on 28-10-2026

Explanation

• Apoptosis is programmed cell death.
• It is a natural process in which the body removes old, damaged, or unwanted cells in a controlled manner.
• Apoptosis plays an important role in embryonic development, such as removing the cells between developing fingers and toes.
• This process helps maintain healthy tissues and prevents damaged cells from surviving unnecessarily.

Last verified on 28-10-2026

Explanation

• Condensation reaction is a chemical reaction in which two molecules join together by removing a small molecule, usually water.
• When monomers join through this process, they can form larger molecules called polymers.

Additional information:

• Hydrolysis is the reverse process, in which water is used to break a chemical bond.

Last verified on 28-10-2026

Explanation

• Spirometry is a pulmonary function test used to measure the volume of air inhaled and exhaled and the rate of airflow.
• The test is performed using an instrument called a spirometer.
• Spirometry is commonly used to help diagnose and monitor respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD).

Last verified on 28-10-2026

Explanation

• Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration due to their random motion.
• Diffusion is a passive process, meaning it does not require cellular energy (ATP).

Additional information:

• Osmosis is the movement of water through a selectively permeable membrane from a region of higher water potential to lower water potential.

Last verified on 28-10-2026

Explanation

• The secondary cell wall develops between the plasma membrane and the primary cell wall after the cell has stopped or largely completed its expansion.
• It is deposited on the inner side of the primary cell wall.
• It often contains cellulose, hemicellulose, and lignin.
• Lignin makes the secondary cell wall stronger and more rigid, providing mechanical support to the plant.

Last verified on 28-10-2026

Explanation

• Nephrolithiasis is the medical term for the formation or presence of stones in the kidneys.
• These stones are also called renal calculi.
• Kidney stones commonly form when minerals and salts, such as calcium oxalate, crystallize in the urine.

Last verified on 28-10-2026

Explanation

• The human kidney contains approximately 12–16 renal pyramids.
• Renal pyramids are cone-shaped structures located in the renal medulla, the inner region of the kidney.
• They contain tubules and collecting ducts that help transport urine toward the renal papillae and minor calyces.

Last verified on 28-10-2026