Question

Describe the mechanism of Respiration in humans, including the role of alveoli.

Hint:

{Alveoli} are specialized structures in the lungs that provide a {large surface area for efficient gas exchange} between air and blood.

Answer 1

Concept: Respiration is a biological process through which the body obtains oxygen and releases carbon dioxide. It involves breathing and cellular respiration that produce energy for body activities.
Step 1:Inhalation (Breathing In) During inhalation:

• The diaphragm contracts and moves downward.
• The rib cage expands.
• The lungs expand and oxygen-rich air enters through the nose, trachea, and bronchi into the lungs.

Step 2:Gas Exchange in Alveoli Inside the lungs are millions of tiny air sacs called alveoli. These structures have:

• Very thin walls
• A large surface area
• A rich supply of blood capillaries

Oxygen from the inhaled air diffuses through the thin walls of the alveoli into the blood, while carbon dioxide from the blood diffuses into the alveoli.
Step 3:Transport of Gases

• Oxygen combines with hemoglobin in red blood cells and is transported to body tissues.
• Carbon dioxide produced by cells is carried back by the blood to the lungs.

Step 4:Exhalation (Breathing Out) During exhalation:

• The diaphragm relaxes and moves upward.
• The rib cage contracts.
• Carbon dioxide-rich air is expelled from the lungs.