Tag: respiratory system of human

Polycyclic aromatic hydrocarbons are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage or other organic substances, such as tobacco and charbroiled meat.
They are the carcinogenic or cancer-causing substance in the tobacco smoke.
Therefore, the correct answer is option B.

Smoking is associated with significant morbidity and mortality. Smoking still remains one of the leading causes of preventable death. Smoking has the dubious distinction of affecting all the systems from head to foot. Cigarette smoking causes many types of cancer. It also increases the risk of cardiovascular diseases. Exposure to tobacco smoke during pregnancy can lead to delivery complications and increase the risk of health problems in the newborn. Quitting smoking significantly reduces the health risks caused by exposure to tobacco smoke. 

Emphysema is a respiratory disorder which occurs due to the inflation or abnormal distension of the bronchioles or alveolar sacs resulting in the loss of their elasticity. Cigarette smoking and chronic bronchitis are the causes of this disease.

Emphysema is. a condition of short breath due to breakdown of alveolar wall and'reduction of respiratory area due to smoking.

• Some amount of air remains behind in the various parts of the respiratory tract.
• The air in the trachea and bronchi (where no diffusion occurs) is called dead space air.
• The air remaining in the alveoli or air sacs in alveolar air. The maximum volume of air that can be exchanged in one breath in and out is called the vital capacity. It is about 5000ml. 
  
  

Tidal Volume (TV) is the amount of volume of air that can be inspired / expired normally.

A person who is born and lives at sea level will develop a slightly smaller lung capacity than a person who spends their life at a high altitude. This is because the partial pressure of oxygen is lower at higher altitude which, as a result means that oxygen less readily diffuses into the bloodstream. In response to higher altitude, the body's diffusing capacity increases in order to process more air. 

The total lung capacity of the adult male is six liters. Tidal volume is the volume of air inhaled in a single, normal breath. Inspiratory capacity is the amount of air taken in during a deep breath, while residual volume is the amount of air left in the lungs after forceful respiration.

• The lungs are the primary organs of the respiratory system in humans and many other animals. Human lung size is determined by genetics, gender, and height. 
• Different animals exhibit different lung capacities based on their activities. For example, cheetahs have evolved a much higher lung capacity than humans in order to provide oxygen to all the muscles in the body, allowing them to run very fast. 
• Elephants also have a high lung capacity due to their large body and their need to take up oxygen in accordance with their body size. Hence, elephants and cheetahs have higher lung capacities than humans.