Functions of the RESPIRATORY SYSTEM1. Regulation of blood pH- change of carbon dioxide level.2. Gas exchange- oxygen from air enter the blood and carbon dioxide from the blood enter air. Cardiovascular system transport oxygen from the lungs to the body cells and carbon dioxide from the body cells to lungs.3. Voice production- air movement pas the vocal cords makes sound and speech possible.4. Olfaction- the sensation of smell occurs when airborne molecules are drawn into the nasal cavity.5. Innate immunity- protects against some microorganisms by preventing them from entering the body.LUNGS Lungs are the principal organs of respiration. Each lung is cone shaped, with its base resting on the diaphragm. Right lung has 3 lobes, left lung has 2 lobes. From trachea- bronchus -bronchi - bronchioles - terminal bronchioles -respiratory bronchioles alveolar ducts - aLveoli.

Mechanic ventilation and respiratory volumes Ventilation, or breathing is the process of moving air into and out of lungs. 2 phases of ventilation: Inspiration or inhalation, movement air into the lungs. Expiration or exhalation, movement of air out of the lungs.

The volume and pressure changes responsible for one cycle of inspiration and expiration can be describe as follows: 1. At the end of expiration, alveolar pressure is equal to atmospheric pressure, and there is no air movement. 2. During inspiration, increased thoracic volume results in increased alveolar pressure. Atmospheric pressure greater than alveolar pressure, and air moves into the lungs. 3. At the end of inspiration, alveolar pressure equal to atmospheric pressure, and there is no air movement. 4. During expiration, decreased thoracic volume results in decreased alveolar volume and increase alveolar pressure. Alveolar pressure is greater than atmospheric pressure, and air moves out of the lungs.

Gas exchange Gas exchange between air and blood occurs in the respiratory membrane of the lungs. Major area of gas exchange is in the alveoli, although some takes place in the respiratory bronchioles and alveolar ducts. The exchange of gases across the respiratory membrane is influenced by the thickness of the membrane, total surface area of the respiratory membrane, and partial pressure of gasses across the membrane. Respiratory membrane thicknessRespiratory membrane increase during certain respiratory diseases Surface area Total surface area of the respiratory membrane is about 70 square meters(m) in the normal adult approximately half the size of basketball court. Under resting conditions, a decrease in the surface area of the respiratory membrane to 1/3 or 1/4 of normal can significantly restrict gas exchange. Partial pressure Gas move from higher to lower concentration. Partial pressure exerted by a specific gas in a mixture of gases, such as air.

Oxygen transport1. After oxygen diffuses through the respiratory membrane into the blood, about 98.5% of the oxygen transported in the blood combines reversibly with heme group of hemoglobin. 2. 1.5 % of remain O dissolved in the plasma.3. Hemoglobin with O bound to its heme groups is called oxyhemoglobin.

Carbon Dioxide Transport and Blood pH Carbon dioxide diffuses from cells, where it is produced, into the tissue capillaries. After carbon dioxide enters the blood, it is transported in 3 ways: About 7% is transported as carbon dioxide dissolved in the plasma. 23% is transported in combination with blood proteins, primarily hemoglobin. 70% is transported in the form of bicarbonate ions.4. Carbon dioxide (CO2) reacts with water to form carbonic acid (H2CO3), which then dissociates to form H+ and bicarbonate ions (HCO3):5. An enzyme called carbonic anhydrase is located inside red blood cells and on the surface of capillary epithelial cells.

Carbonic anhydrase increases the rate at which CO react with water to form H+ and HCO3in the tissue capillaries Carbonic anhydrase promotes the uptake of CO by red blood cells In the capillaries of the lungs, the process is reversed, so that H+ and HCO3 combine to produce HCO3, which then forms CO and HO. The CO diffuses into the alveoli and is expired. Carbon dioxide has an important effect on the pH of blood. CO increase, blood pH decrease (become more acidic) because CO react with H O to form HCO3 . The H+ result from the dissociation of HCO3 are responsible for the decrease in pH.

SUMMARY External respiration is the exchange of gases between alveolar air and pulmonary blood capillaries. Internal respiration is the exchange of gases between systemic tissue capillaries and systemic tissue cells. 98.5% of O carried by the irons of the heme in hemoglobin, 1.5 % is dissolved in plasma. CO transported in 3 ways, 70% is converted to bicarbonate ions (HCO3), 23% combine with the globin of hemoglobin, 7% is dissolved in plasma. Partial pressure of a gas (Px) is the pressure exerted by the gas in a mixture of gases. pulmonary ventilation(breathing) consists of inhalation and exhalation, the movement of air into and out of lugs. Air flow from higher pressure to lower pressure.