Respiratory system:

• Nostrils​ =} Nasal cavity =} Pharynx =} Larynx =} Trachea =}Bronchus =} Bronchioles =}Alevelos =} Blood.

• Nostrils : Air enters into our body through Nostrils.

• Nasal cavity : In nasal cavity the air is filtered. The cavity has hairs growing from the sides which remove dust In the air. And the cavity is moist.

• Pharynx : This is the common passage of digestive tract and wind pipe. Here, Epiglottis a flap like muscular valve controls the food and wind to thier respective passages.

• Layrnx : This part contains our vocal cords. when air moves over them, they vibrate and produce sound!

• Trachea : Wind pipe channeling to trachea. and to lungs.

• Bronchus :Wind pipe is divided into ​two pipes one leading to each lung.

• Bronchioles : The Bronchus is divided into further smaller branches called Bronchioles.

• Alevelos : These are clusters of air sacs. They are numerous. here blood capillaries take up the oxygen and expel CO2.

• Blood : And finally oxygen dissolves in blood and travels to each and every cell.


DIAPHRAGM.
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An important part which helps in respiration. it is done shaped.

Mechanism of diaphragm :

During inhalation the dome shaped diaphragm flattens and the volume of chest cavity increases. As a result air outside rushes into the lungs.

During exhalation the diaphragm relaxes and retains it dome shape. And as a result the volume of chest cavity decreases and air inside the lungs rushes out.

That's all🙂

**Human Respiratory System**

The human respiratory system is a complex network of organs and tissues responsible for the exchange of gases between the body and the environment. It plays a vital role in supplying oxygen to the body's cells and removing carbon dioxide, a waste product of cellular metabolism. This process of gas exchange is essential for the functioning of all body systems.

**Organs of the Respiratory System:**

1. *Nose and Nasal Cavity:* The respiratory system begins with the nose and nasal cavity. The nose acts as an entrance for air, filtering and humidifying it. The nasal cavity is lined with tiny hairs and mucus-producing cells that trap and remove foreign particles.

2. *Pharynx:* Located at the back of the throat, the pharynx serves as a passageway for both air and food. It directs air towards the larynx and food towards the esophagus.

3. *Larynx:* Commonly known as the voice box, the larynx contains vocal cords that vibrate to produce sound when air passes through.

4. *Trachea:* Also called the windpipe, the trachea is a tube that connects the larynx to the bronchi. It is made up of rings of cartilage that provide structural support and prevent collapse.

5. *Bronchi and Bronchioles:* The trachea divides into two bronchi, each leading to a lung. Within the lungs, the bronchi further divide into smaller bronchioles, which eventually terminate in tiny air sacs called alveoli.

6. *Lungs:* The two lungs are the primary organs of respiration. They are located in the chest cavity and are protected by the ribcage. The lungs are spongy and elastic, allowing them to expand and contract during breathing.

7. *Alveoli:* These small air sacs are the site of gas exchange. They are surrounded by a network of capillaries, where oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled.

**Mechanism of Breathing:**

Breathing is a rhythmic process that involves two phases: inhalation (inspiration) and exhalation (expiration).

1. *Inhalation:* During inhalation, the diaphragm contracts and moves downward, while the intercostal muscles between the ribs contract, lifting the ribcage upward and outward. This increases the volume of the chest cavity, causing a decrease in air pressure within the lungs. As a result, air rushes in through the nose or mouth, down the trachea, and into the lungs.

2. *Exhalation:* Exhalation is a passive process that occurs when the diaphragm and intercostal muscles relax. This decreases the volume of the chest cavity, increasing the air pressure within the lungs. The excess air is then forced out through the nose or mouth.

**Conclusion:**

The human respiratory system is a remarkable mechanism that ensures the continuous supply of oxygen and removal of carbon dioxide from the body. Its intricate network of organs and tissues work together to facilitate efficient gas exchange, enabling the body to carry out vital functions and maintain homeostasis. Understanding the respiratory system is crucial for appreciating the importance of breathing and maintaining overall health and well-being.