RESPIRATORY SYSTEM

The respiratory system main task is to supply oxygen to the blood and getting rid of waste gases. Carbon dioxide is the primary gas that the blood gets rid of. The upper structures of the respiratory system are combined with the sensory organs of smell and taste and the digestive system. When you inhale (breathing in) your skeletal muscle and the diaphragm contract, which then enlarge the chest cavity and cause the lungs to draw in air. This creates a partial vacuum in the thoracic cavity, air passes through the nose, pharynx, larynx, trachea, and then into the two bronchi to the lungs. Oxygen and carbon dioxide pass between the blood and the air in the alveoli, which are at the end of the smallest bronchi. Oxygen diffuses from the inhaled air through the alveoli walls into the capillaries. The lungs contain more than 300 million alveoli. When you exhale or breathe out, your skeletal muscles and diaphragm return to the relax position which decrease the size of the chest cavity and therefore pushes the air out of the lungs. The rib cage serves as a structural support for the whole thoracic arrangement, and peural membranes help provide lubrication for the respiratory organs so that they are not chaffed during respiration. The air we exhale contains 100 times more carbon dioxide than inhaled air. In a resting position a healthy individual will inhale and exhale approximately 16 time per minute.

LUNGS

LUNGS


The lungs are a pair of organs located in the chest that performs respiration. Humans have 


two lungs; the left lung is divided into two lobes and the right lung is divided into three. The 


lungs are located in the chest cavity inside the rib cage. They are made of elastic, spongy 


tissue as they stretch out and constricts while you breathe.

The trachea and the bronchi are the airways that bring the air to the lungs. They are made of


 smooth muscleand cartilage, which allows the airways to constrict and expand. The duty of


 the lungs and the airways is to bring in fresh air, rich in oxygen and as well as to get rid of


 carbon dioxide waste made by the cells. They also regulate the concentration of hydrogen


 ions in the blood.


The diaphragm and the intercostal muscles, which are the muscles located between the ribs,


contract and expand the chest cavity as you inhale. The pressure in the chest cavity below 


the outside pressure is lowered because of the expansion. Air flows into the airways and


 inflates the lungs. On the other hand, the diaphragm and intercostal muscles relax and the 


chest cavity gets smaller when you exhale. The decrease in the volume of the cavity increases


 the pressure in the chest cavity, air from the lungs then travels out of the airways. This cycle


 is repeated every time you breathe.


The air you breathe goes into the trachea and travels down to the vocal cords in the larynx up


 to the bronchi. From the bronchi, the air then passes through each lung until it reaches the


 alveoli. The oxygen concentration in each air sac is high; this causes the oxygen to pass across


 the alveolar membrane into the pulmonary capillary. The oxygen then binds to the


 haemoglobin at the beginning of the pulmonary capillary and carbon dioxide is released. 


Carbon dioxide concentration is high in the pulmonary capillary so carbon dioxide leaves the


 blood by passing through the alveolar membrane into the air sac. These processes happen in


 fractions of a second. When the carbon dioxide leaves the alveolus, the oxygen enriched-


blood goes back to the heart.


There are a number of health conditions that affect the lungs. These conditions may be


 divided into two categories: conditions that make it hard to breathe and conditions that


 damage the ability of the lungs to exchange carbon dioxide for oxygen. Some of the most


 common health conditions that make it hard to breathe are: Asthma, Bronchitis,


 Emphysema, Apnea and Pneumothorax.


The most common health conditions that minimize and prevent gas exchange are: Pulmonary


 Edema, carbon monoxide poisoning and smoke inhalation.


The peak of your lung function is in the late teens and early twenties. In your late twenties,


 lung function can decline up to about 1 percent every year. If you are a regular smoker, it can


 decline up to 2 percent every year. People who have been smoking since their teens should 


consider stopping at around their late twenties or early thirties at the risk of getting lung 


cancer. Though not all people who smoke acquire lung cancer, they are still the most at risk.