Respiratory System

Respiratory System Outline:

Nose The most external organ, air is inhaled and exhaled through nose, has different mechanisms for cleaning and condensing the inhaled air
Larynx Also known as sound box, formed of cartilages, connects the tracheo to the laryngopharynx
Trachea Tubular structure with about 1 inch diameter, composed of 15-20 C shaped cartilages that keep it dilated
Bronchi Left and Right dividions of trachea, enters the lungs and divide into secondary bronchi
Lungs Main organs of respiration, two in number (one on each side of heart) Conical in shape, divided into lobes
Conductive Parts Parts of respiratory system where exhcange of gases does not take place, include Nose, larynx, trachea, and bronchi.
Respiratory Parts Parts of respiratory system where exchange of gases takes place, Incude Lungs
Functions Gaseous Exchange, Excretion of carbon dioxide, Oxygenation of blood

Introduction to Respiratory System:

Respiratory System

Respiratory System

Respiratory system is the system of respiratory passages, lungs and respiratory muscles of human body. Respiratory system is responsible for exchange of gases between the human body and the surroundings. In the process of exchange of gases, human body gains oxygen and gets rid of carbon dioxide. Other gases of the atmosphere have no significant role in human respiratory system. Respiratory system is extremely important for human body because the process of respiration cannot be stropped even for a few seconds. If the process of respiration stops even for a minute or two, the condition will become serious and will ultimately end in death.

Organs of human respiratory system:

The main organs of human respiratory system are lungs and respiratory passages. Muscles of respiration also form a component of respiratory system but there importance is rather little as compared to lungs and respiratory passages.
Lungs are the organs of human body where gaseous exchange take place. Human beings have two lungs known as the right and left lungs. Lungs are soft, spongy and very elastic. For more details of lungs anatomy, visit “”.
Respiratory Passages:
Respiratory passages or air-ways are the conducting portions of human respiratory system. Here no exchange of gases take place, but they guide the air to go to the lungs and not anywhere else in the body. Conducting portion of the human respiratory system consists of; Traches, Bronchi, Bronchioles, Alveolar sacs and Alveoli.

Lungs and Conductive passages

Lungs and Conductive passages


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Functions of Respiratory System:

  1. GASEOUS EXCHANGE: Main function of respiratory system is gaseous exchange. Through respiratory system new air is always brought into the body and used air is expelled out. In this way oxygen is gained and carbon dioxide is lost by the body.
  2. EXCRETION OF CARBON DIOXIDE: Respiratory system is the major system for excretion of carbon dioxide from the body. Carbon dioxide is produced as a result of metabolic break down of carbohydrates in body and must be eliminated quickly. Carbon dioxide is brought to the lungs by blood and is lost from the lungs through gaseous exchange with fresh air in lungs.
  3. OXYGENATION OF BLOOD: Oxygen is required by the body for break down of food and must be continuously supplied for continuous supply of energy. Supply of oxygen is maintained by respiratory system.

Learn Respiratory Systems at

The details of the respiratory system are divided in the following sections;