Chapter 17- Respiratory system

Describe the transport of Oxygen in the blood

- In the lungs, the oxygen forms a weak bond with the iron portion of hemoglobin, creating oxyhemoglobin - oxyhemoglobin travels through the circulatory system to the tissue cells - Once there, the difference in pH between the arterial and venous blood is enough to break the bond between the oxygen and the hemoglobin - The oxygen is then released to the tissues

The role of muscles in Inspiration

- The external intercostal muscles pull the ribs upward and outward, widening the thoracic cavity. - The internal intercostals help elevate the ribs - the diaphragm contracts, flattens, and drops, pressing the abdominal organs downward and enlarging the thoracic cavity. - Air rushes in to equalize pressure

The role of muscles in Expiration

- The internal intercostal muscles pull the ribs downward as the external intercostals relax. - The diaphragm relaxes, bulging upward and pressing against the base of the lungs, reducing the size of the thoracic cavity. - Air is pushed out of the lungs

functions of the respiratory system

- Voice Production - Smell and taste - Acid-base balance - Oxygen and Carbon Dioxide Exchange

Describe the process of gas exchange at the alveoli and at the body's tissues.

1. Inspired air has a PO2 (Partial Pressure of Oxygen) of 159 and a PCO2 (partial pressure of carbon dioxide) of 0.3. 2. When it arrives at the alveoli, air has a PO2 of 104 and a PCO2 of 40. 3. On the other side of the alveoli's thin membrane are pulmonary capillaries that contain venous blood. This blood has a PO2 of 40 and a PCO2 of 46. 4. The differences in partial pressures of O2 and CO2 on either side of the respiratory membrane cause O2 to move out of the alveoli and into the capillaries and CO2 to move out of the capillaries into the alveoli. (In other words, the red blood cells in the capillaries unload CO2 and load oxygen.) The CO2 is later exhaled through the lungs. 5. Blood in the capillaries now has a PO2 of 100 and a PCO2 of 40. 6. This oxygen-enriched blood travels to the heart's left ventricle, where it's pumped to the body's tissues. 7. Meanwhile, cells in the body's tissues have been using oxygen for energy production and producing CO2 as a by-product. The fluid surrounding the cells has a PO2 of 40 and a PCO2 of 46. 8. When the blood from the left ventricle (with a PO2 of 100) arrives at the tissues (with a PO2 of 40), oxygen diffuses out of the blood and into the tissues. Simultaneously, carbon dioxide diffuses from the tissues (PCO2 of 46) and into the blood (PCO2 of 40). 9. Once it has released oxygen to the tissues and absorbed CO2, the capillary blood has a PO2 of 40 and a PCO2 of 46. Systemic capillaries carry this oxygen-depleted blood away from the tissues and toward the heart's right ventricle, where it will be pumped back to the lungs.

Describe the transport of Carbon Dioxide in the blood

Carbon dioxide is transported from the tissues to the lungs in three ways: 1.) About 10% is dissolved in the plasma 2.) Another 20% is bound to hemoglobin, forming carbamino hemoglobin. (Hemoglobin can transport both O2 and CO2 at the same time because they bind to different sites on the hemoglobin molecule) 3.) The vast majority—about 70%—is carried in the form of bicarbonate ions. This occurs because when CO2 dissolves in plasma, it reacts with the water in the plasma to form carbonic acid. Carbonic acid then dissociates into bicarbonate and hydrogen ions.

Life lesson: Emphysema

Emphysema is a progressive lung disease in which lung tissue surrounding alveoli is destroyed. This leaves alveoli unsupported, allowing them to enlarge and eventually rupture. Alveolar walls fuse into large irregular spaces that offer less area available for gas exchange. The alveoli also lose elasticity and the ability to recoil. Consequently, air becomes trapped in the lungs. Over time, the trapped air causes the diameter of the chest to enlarge, and the chest assumes the shape of a barrel. (A person with emphysema is often said to be "barrel-chested.") People with emphysema must work to exhale; they can expend three to four times the normal amount of energy just to breathe.

List the organs of the respiratory system and describe the functions of each.

The upper respiratory tract consists of the nose, nasopharynx, oropharynx, laryngopharynx, and larynx. These structures warm and humidify inspired air. They're also responsible for the senses of smell and taste as well as chewing and swallowing food. The lower respiratory tract consists of the trachea, bronchi, and lungs. The trachea and the bronchi distribute air to the interior of the lungs; deep within the lungs is where gas exchange occurs.

Pleurisy

an inflammation of the pleural membranes that causes painful breathing