Human Respiratory System - Pathway and Function for NEET Define Respiratory System

The human respiratory system is a biological system responsible for the intake of oxygen and the removal of carbon dioxide, essential for cellular respiration. It consists of a series of organs, including the nose, pharynx, larynx, trachea, bronchi, and lungs, working together to facilitate breathing.

The primary function of this system is gas exchange, where oxygen from the air is transported to the bloodstream, and carbon dioxide, a waste product of metabolism, is expelled. The process is controlled by the diaphragm and intercostal muscles, which regulate breathing movements.

This system plays a crucial role in maintaining homeostasis, pH balance, and overall energy production in the body. Disorders of the respiratory system, such as asthma, pneumonia, and chronic obstructive pulmonary disease (COPD), can significantly impact health.

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 the Respiration System

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

1. Upper 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.

2. Lower Respiratory System-

• Trachea (Windpipe)- A flexible tube reinforced with C-shaped cartilage rings, ensuring airflow to the lungs.

• Bronchi- The trachea divides into two bronchi, which direct air into each lung.

• Bronchioles- Smaller branches of the bronchi, leading to alveolar sacs.

• Alveoli- Tiny air sacs surrounded by capillaries where oxygen enters the blood, and carbon dioxide is expelled.

• Lungs- The primary respiratory organs, are divided into lobes—three in the right lung and two in the left.

• Diaphragm- A dome-shaped muscle that separates the chest from the abdomen, playing a vital role in breathing by contracting and relaxing.

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

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

Respiration is a vital biological process that ensures the survival of living organisms by supplying oxygen and removing carbon dioxide. The main functions of respiration include-

1. Oxygen Supply- Provides oxygen to body cells for energy production through aerobic respiration.

2. Energy Production- Converts glucose and oxygen into ATP (adenosine triphosphate), the energy currency of the body.

3. Carbon Dioxide Removal- Expels carbon dioxide, a waste product of cellular metabolism, preventing toxicity.

4. Maintaining pH Balance- Regulates blood pH by controlling carbon dioxide levels, preventing acidosis or alkalosis.

5. Heat Production- Generates heat as a byproduct of metabolic reactions, maintaining body temperature.

6. Speech and Vocalization- Supports sound production by controlling airflow through the vocal cords.

7. Detoxification- Helps remove volatile waste substances, such as alcohol and certain drugs, through exhalation.

8. Enhancing Circulation- Works closely with the circulatory system to distribute oxygen-rich blood throughout the body.

Conclusion

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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