Respiratory System Overview

Respiratory System Overview

• The respiratory system involves between 17,000 and 29,000 breaths per day
• A deep breath can capture 3-4 liters of air in the lungs
• Breathing is an involuntary process
• The respiratory system is essential and cannot be consciously controlled

Main Parts of the Respiratory System

• Trachea: A tube connecting the throat to the lungs. It carries air.
• Bronchi: Two branches from the trachea, one leading to each lung. Air travels down the bronchi to the bronchioles.
• Bronchioles: Smaller branches of the bronchi, leading to the alveoli.
• Alveoli: Tiny air sacs in the lungs surrounded by blood vessels, where gas exchange occurs. There are millions of these in the lungs.

The Pathway of Air

• Air enters through the nose or mouth
• Travels down the pharynx
• Enters the trachea
• Travels through the bronchi
• Enters bronchioles
• Finally reaches alveoli

The Trachea

• The trachea is supported by rings of cartilage that keep it open, allowing air to flow freely.
• The trachea has mucus-producing cells and cilia.
• Mucus traps dust and other airborne particles.
• Cilia sweep the trapped material out of the trachea. Particles may be swallowed or expelled by coughing or sneezing.

Gas Exchange

• Alveoli fill with air to allow gas diffusion.
• Millions of alveoli in the lungs provide a large surface area for efficient gas absorption.
• Alveoli walls have a thin, single layer of flattened cells to minimise the distance gas needs to travel.
• A dense network of capillaries surrounds the alveoli to remove carbon dioxide and allow oxygen to enter the bloodstream.
• Hemoglobin in red blood cells carries oxygen throughout the body.

Breathing

• Breathing involves the diaphragm (a large dome-shaped muscle) and muscles between the ribs.
• The process is involuntary, but can be consciously overridden temporarily.
• During inhalation, the diaphragm contracts (moving downwards) and the rib cage expands outwards, creating a larger space for air to enter the lungs.
• During exhalation, the diaphragm relaxes (moving upwards), and the rib cage contracts, forcing air out.
• The human brain controls breathing by monitoring CO2 levels in the blood. Higher CO2 levels trigger an increase in breathing rate.

Diseases of the Respiratory System

• Tuberculosis (TB): An infectious disease caused by bacteria. Symptoms include fever, cough, weight loss, tiredness, and chest pain. Diagnosis involves chest X-rays or examining bodily secretions.
• Severe Acute Respiratory Syndrome (SARS): A disease that spread from China to other countries. Symptoms are flu-like, high fever, shortness of breath, dry cough, sore throat, headache and exhaustion. Diagnosis is based on chest X-rays and lab tests.

Respiratory System Cancers

• Respiratory system cancers are often caused by tobacco smoke.
• Carcinogens in tobacco smoke contribute to many cancers (mouth, lungs, larynx, pancreas, esophagus and bladder).

Chronic Obstructive Pulmonary Disease (COPD)

• COPD, about 90% of cases are caused by smoking.
• It is a chronic, progressive disease involving both obstructive bronchitis(long-term cough, inflammation and mucus) and emphysema.
• Emphysema damages the alveoli, reducing elasticity and surface area available for gas exchange.
• There is no cure for COPD. Damage to alveoli is permanent.

Effects of Smoking

• Smoking causes many health problems, including cancer, COPD, and asthma.
• Problematic substances in tobacco smoke include nicotine (addictive), carbon monoxide (binds more strongly to red blood cells than oxygen) and tar (accumulates in the alveoli, hindering gas exchange).

Explore the essential functions and structures of the respiratory system in this quiz. Learn about the pathway of air through various components such as the trachea, bronchi, bronchioles, and alveoli. Test your knowledge on how respiratory processes function involuntarily to sustain life.