Human Respiratory System
The Human Respiratory System is a network of organs and tissues that help you breathe. It facilitates the exchange of gases—intake of oxygen from the atmosphere and release of carbon dioxide from the body. The primary organs of this system are the lungs.
Note: Covered under Class 10 Science (Chapter 6: Life Processes) NCERT Syllabus.
Anatomy: Pathway of Air
Air travels through the following path to reach the blood:
- Nostrils: Air is taken into the body. Fine hairs and mucus here filter dust particles.
- Pharynx & Larynx: The passage leads to the throat.
- Trachea (Windpipe): A tube reinforced with rings of cartilage. These rings ensure that the air passage does not collapse.
- Bronchi: The trachea divides into two bronchi (one for each lung).
- Bronchioles: Bronchi divide into smaller tubes called bronchioles.
- Alveoli: Balloon-like structures at the end of bronchioles where gas exchange occurs.
Fig 1: Human Respiratory System (Schematic).
Mechanism of Breathing
| Inhalation (Breathing In) | Exhalation (Breathing Out) |
|---|---|
| Ribs lift up. | Ribs move down. |
| Diaphragm flattens. | Diaphragm relaxes (domed shape). |
| Chest cavity becomes larger, air is sucked in. | Chest cavity becomes smaller, air is pushed out. |
Exchange of Gases (Alveoli)
The alveoli provide a massive surface area for gas exchange. Their walls contain an extensive network of blood vessels. Oxygen from the air diffuses into the blood, and carbon dioxide from the blood diffuses into the alveoli to be exhaled.
Chapter Assessment
1. Why does the trachea not collapse when there is no air?
The trachea is supported by rings of cartilage which are C-shaped. These cartilaginous rings provide structural strength and prevent the windpipe from collapsing.
2. How are alveoli designed to maximize gas exchange?
(i) They have very thin walls.
(ii) They are surrounded by a rich network of blood capillaries.
(iii) They provide a large surface area (approx. 80 m²).
(ii) They are surrounded by a rich network of blood capillaries.
(iii) They provide a large surface area (approx. 80 m²).
Reference: NCERT Class 10 Science.
Reviewed under Sarkari Service Prep Academic Policy.
Reviewed under Sarkari Service Prep Academic Policy.
No comments:
Post a Comment