The Importance of a Healthy Respiratory System

Air pollutant	Harmful substances	Effect on respiratory system
Cigarette smoke	Nicotine, Tar	Nicotine is the drug that causes addiction to cigarette smoking. Nicotine cause rapid heartbeat, increased blood pressure and rapid breathing. The diseases related to nicotine include emphysema, hear disease and stroke Tar contains carcinogens (substances that cause cancer). It also irritates the respiratory tract, causing ‘smoker’s cough’
Gases from factories	Sulphur dioxide, nitrogen dioxide	Sulphur dioxide can cause irritation of the respiratory system. It can cause both temporary and permanent damage to the lungs.
Exhaust fumes	Carbon monoxide	Carbon monoxide combines with haemoglobin in the blood faster than oxygen can hence it is a poisonous gas which cause suffocation. Low concentration of carbon monoxide can cause dizziness, headaches and fatigue whereas high concentrations can be fatal.
Haze	Smoke, dust	Continuous exposure to particulate matter cause coughing, nasal congestion, watery nose, constant sneezing and chest pain. Those who are very likely to be affected by haze are children, the elderly and people with illnesses like asthma, bronchitis and pneumonia.

Diseases of the respiratory system

Asthma is caused by the narrowing of the fine airways (bronchi and bronchioles) due to the contraction of muscles in their walls. This is perhaps because of sensitivity to air pollutants including smoke. A patient will find it difficult to breathe, wheezing and feeling tightness in the chest.

Bronchitis is caused by the inflammation of the lining of the bronchioles. This may be due to infection by bacteria or viruses or chemicals such as those found in tobacco smoke. 'Smoker's cough' is an early sign of chronic bronchitis. In several cases, the patient may turn blue which is especially noticeable at the lips and fingers due to poor oxygenation of blood.

Lung Cancer is cause by change in the cells inside the lung such that they divide out of control and produce lumps of cells (tumours) which interfere with the normal functions of the lungs. This diseases may not have any symptoms. When it is detected, the cancer cells may have spread from the lung to other organs.

Emphysema is a condition in which the structure of the alveoli is broken down by coughing. This reduces the surface area for gas exchange. The patient cannot take in enough oxygen and become very short of breath

Heart disease caused by nicotine that raises the blood pressure and increases the level of 'bad' cholesterol in the blood. This makes a smoker more likely to suffer from a stroke or a heart attack 

The Transport of Oxygen in The Human Body

Source: http://www.drtummy.com

During inhalation, air is taken into the lungs through the nasal cavity, passing through the trachea, bronchi, bronchioles and finally alveoli. The air reaches the alveoli is rich in oxygen and poor in carbon dioxide. The blood from the heart that reaches the capillaries surrounding the alveoli is poor in oxygen and rich in carbon dioxide.

Oxygen diffuses from the alveoli into the red blood cells in the capillaries. At the same time , the red blood cells in the capillaries release carbon dioxide which diffuses into the alveoli.

Red blood cells contain the red pigment called Haemoglobin. Haemoglobin combine with oxygen to form oxyhaemoglobin. Oxyhaemoglobin from the lung is flow to the heart.

Source : http://www.drtummy.com

When the oxyhaemoglobin from the heart reaches to the body tissue cell, oxygen has a higher concentration in the capillaries than in the body cells. So, oxyhaemoglobin releases oxygen which diffuses into the body cells. At the same time, carbon dioxide has higher concentration in the body cells than in the capillaries. So, carbon dioxide diffuses into the blood capillaries. Blood contain carbon dioxide next flow into the heart.

 

Source : http://www.tutorvista.com/content/biology/biology-ii/respiration/human-beings-gaseous-exchange.php

A Model of The Human Respiratory System

 

Glass tube ---> Trachea
Ballons ---> Lung
Bell jar ---> Thoracic Cavity
Rubber sheet ---> Diaphragma
Y-tube ---> Bronchus

1. When the rubber sheet is pulled down, the pressure inside the bell jar decreases. Air from outside enter the balloons
2. When the rubber sheet is pushed up, the pressure inside the bell jar increases. Air is forced out of the balloons

Mechanisms of Inhalation and Exhalation

Inhalation Mechanisms

1. Diaphragm muscles contract and flattens out
2. Volume of thoracic cavity increases
3. Air pressure inside thoracic cavity decreases
4. Air flow into lung
5. Ribcage move forward and upward

Exhalation Mechanisms

1. Diaphragm relax and arches upwards
2. Volume of thoracic cavity decreases
3. Air pressure inside thoracic cavity inrcreases
4. Air flow out of the lung
5. Ribcage move downward and inward

The Human Respiratory System

The Structure of Human Respiratory System and Human Lung