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Human Respiratory System - Pathway and Function for NEET

Define Respiratory System

Last updated date: 16th Mar 2023
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All the organs that help in gas exchange form the respiratory system. A respiratory system is a group of organs in humans that function in respiration, including the nose, nasal passages, pharynx, larynx, trachea, bronchi, and lungs. 

The blood gets oxygen from breathing. The mechanism through which cells obtain energy from glucose is known as respiration. Cells respire by breaking down food molecules (such as sugar) and releasing the energy held in the food. To release the energy, cells require oxygen and get rid of carbon dioxide produced from cells. This transport and exchange of gases occur in the blood.

In this article, the respiratory system in humans and the pathway of respiration are discussed along with the human respiratory system diagram. This article gives an overview of the human respiratory system and its functions in a brief and elaborative manner.

What is the Respiratory System?

The respiratory system in living organisms is in charge of gas exchange. The lungs are the primary respiratory organs in humans. The human respiratory system is made up of two lungs, a trachea, bronchi, alveoli, and a diaphragm.

Respiration consists of the following steps: 

(i) Breathing is the process by which atmospheric air is drawn in and CO2-rich alveolar air is expelled. 

(ii) Gas diffusion (O2 and CO2) across the alveolar membrane. 

(iii) Gas transport via the blood.

Parts of Respiration System

The respiratory system is divided into lower and upper respiratory systems. The nose, nasal cavity, nasopharynx, and pharynx are all part of the upper respiratory system. The larynx, trachea, bronchi, bronchioles, and alveoli of the lungs make up the lower respiratory system. 

Nose: The nose and mouth allow air into the body. Mucous membranes line the inside of the nose. To catch dirt, it contains cilia (tiny hairs). 

  • Epiglottis: When you swallow, the epiglottis is a flap of tissue that closes across the trachea. 

  • Larynx: The vocal cords are housed in the larynx, which aids in sound generation. 

  • Pharynx: There are two passageways in the throat - one for air and one for food. The trachea is a tube that directs air to the lungs. Bronchi are the channels that allow air to enter the lungs. Bronchioles are small tubes that branch off the bronchi and end in the alveoli sac.

  • Alveoli: These are minute air sacs found at the extremities of the bronchi's smallest branches. In the thoracic cavity, there is only one set of lungs. Lungs are separated into lobes by which oxygen is transported into the circulation and carbon dioxide is eliminated (right and left lobe). 

  • Diaphragm: Lungs and the abdomen are separated by the diaphragm, which is a dome-shaped muscle. The diaphragm is responsible for supplying air to the lungs.

Organs of Respiration

The lungs are the most essential organ in the respiratory system. Other respiratory components include the nose, trachea, and breathing muscles (the diaphragm and the intercostal muscles). 

Nose: It is a channel for oxygen to get into your lungs. Hair and mucus line the inside of the filter, which helps to filter bigger particles from the air we breathe. 

  • Pharynx: The pharynx is a muscular funnel tunnel that helps with swallowing and is utilised by food, liquid, and air. At the bottom of this tube is where the epiglottis is attached. 

  • Trachea: The outside of the trachea is lined with C-shaped cartilage, while the inside is lined with mucus and cilia. The C-shaped cartilage in the neck and head keeps the tube flexible and prevents it from collapsing. 

  • Bronchi: Airways are bronchial passageways that connect the trachea to the bronchioles. To assist filter the air, these tubes are coated with mucus and cilia. There are three types of bronchi: primary, secondary, and tertiary.

  • Bronchioles: Bronchioles are tiny tubes that assist in the delivery of oxygen to the alveoli.

  • Alveoli: Alveoli are capillary-encircled clusters of thin-walled sacs that are present in the lungs that allow for rapid exchange of oxygen and carbon dioxide.

Human Respiratory System Diagram
The Human Respiratory System

The Human Respiratory System

Pathway of Respiration

Respiration takes its path from the nose/mouth, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli. The air moves into the nose and then passes through the pharynx and trachea to the lungs. In the lungs, it moves from bronchi to bronchioles and then lasts to alveoli where the exchange of gases occurs through the epithelium. 

Function of Respiration

The respiratory system's primary role is to provide oxygen to the blood so that it can provide oxygen to all regions of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. The respiratory system's method of delivering oxygen to the blood is through gas exchange.

This system prevents dehydration, temperature fluctuations, and pathogen invasion. The larynx part of the respiratory system helps in making communication noises. The nose of the respiratory system helps in making sense of smell easier.


This article provides all the necessary details about the human respiratory system with respect to the NEET syllabus. It gives insight into the different parts and organs of the respiratory system. It also talks about the pathway involved in respiration, and how air enters through the nostrils and reaches the lungs. We can breathe because of our lungs and respiratory system. They bring oxygen into our bodies (this is known as inspiration or inhalation) and exhale carbon dioxide (called expiration, or exhalation). Respiration is the exchange of oxygen and carbon dioxide.

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FAQs on Human Respiratory System - Pathway and Function for NEET

1. What is the difference between Breathing and Respiration?



Breathing is the process of getting oxygen and releasing carbon dioxide.

Respiration is the process of getting energy from food.

It occurs in the lungs.

It occurs in both the lungs and the mitochondria.

It is a physical and voluntary process.

It is a chemical and involuntary process.

In breathing, no energy is produced.

Respiration leads to the production of energy.

Here energy is used in breathing.

Energy is produced in the form of ATP.

CO2 and H2O are formed as byproducts.

These are not produced but released from the lungs.

2. Pathways of air move into the lungs-external nostrils, vestibules, nasal chambers, internal nares, nasopharynx, X, larynx, and trachea. What exactly is X?

Pathway of air is through the respiratory tract: external nares, nose, pharynx, glottis, larynx, trachea, primary left and right bronchus, secondary bronchus, tertiary bronchus, bronchiole, alveolus. Glottis is a respiratory passage that opens into the larynx. The epiglottis is a flap-like structure situated close to the glottis. The mucous membrane makes up the epiglottis. When we swallow, the epiglottis opens and shuts with elastic cartilage flaps, closing off the airway. This flap covers the glottis during breathing to avoid food particles from entering it.