EAP Ch. 15 - The Respiratory System Flashcards
Fact
All of our cells must obtain oxygen to carry out cell respiration to produce ATP. Just as crucial is the elimination of the CO2 produced as a waste product of cell respiration.
Divisions of the Respiratory System
List and describe 3 parts of the upper respiratory tract
- Upper respiratory tract - consists of the parts outside the chest cavity: the air passages of the nose, nasal cavities, pharynx, larynx, and upper trachea.
- Nose; Nasal cavities (separated by nasal septum); Nasal mucosa (lining); 3 shelf-like bones called conchae project from the lateral wall of each nasal cavity;** Olfactory receptors; Paranasal sinuses** (lighten the skull and provide resonance for the voice)
- Pharynx; Uppermost portion is the nasopharynx, which is behind the nasal cavities. The soft palate is elevated during swallowing to block the nasopharynx and prevent food or saliva from going up rather than down. The oropharynx is behind the mouth. The laryngopharynx opens anteriorly into the larynx and posteriorly into the esophagus.
- Larynx - voice box and air passageway. During swallowing, the larynx is elevated and the epiglottis closes over top.
Divisions of the Respiratory System
Describe the parts of the lower respiratory tract
- Lower respiratory tract - consist of the part found within the chest cavity: the lower trachea and the lungs themselves, which include the bronchial tubes and alveoli
- Trachea - the right and left primary bronchi are the branches of the trachea that enter the lungs. Like an upside down tree - branches that get smaller and smaller are the bronchioles. No cartilage is present in the walls of the bronchioles. The smallest bronchioles terminate in clusters of alveoli, the air sacs of the lung (the function units of the lungs). The pleural membranes are the serous membranes of the thoracic cavity. The parietal pleura lines the chest wall, and the visceral pleura is on the surface of the lung. Between the pleural membranes is serous fluid, which prevents friction and keeps the two membranes together during breathing.
Divisions of the Respiratory System
Describe what asthma is and how it comes about
As part of the allergic response, the smooth muscle of the bronchioles constricts. Because there is no cartilage present in their walls, the bronchioles may close completely. As part of inflammation, the lining of the bronchioles swells and the secretion of mucus increases, perhaps markedly, so the already constricted bronchioles may become clogged or completely obstruct the mucus. Chronic asthma is a predisposing factor for emphysema. When obstructed bronchioles prevent ventilation of alveoli the walls of the alveoli begin to deteriorate and break down, leaving large cavities that do not provide much surface area for gas exchange.
Divisions of the Respiratory System
What is Bacterial Pneumonia?
Bacterial pneumonia: a disease in which alveoli become filled with fluid.
Divisions of the Respiratory System
Describe what Pulmonary Surfactant and Repiratory Distress Syndrome are
- Pulmonary surfactant - a lipoprotein secreted by alveolar type II cells, also called septal cells. Surfactant is mixed with the tissue fluid within the alveoli and decreases its surface tension, permitting inflation of the alveoli. Normal inflation of the alveoli in turn permits the exchange of gasses.
- Respiratory distress syndrome: in premature infants whose lungs have not yet produced sufficient quantities of pulmonary surfactant. In adults, this is called acute respiratory distress syndrome.
Divisions of the Respiratory System
Describe the pleural membranes and the respiratory muscle that form the chest cavirty
Pleural membranes and the respiratory muscle that form the chest cavity: the diaphragm (dome-shaped muscle below the lungs) and intercostal muscles (between the ribs - pulls them up and down when breathing)
Mechanism of breathing
Describe Ventilation
The movement of air to and from the alveoli (i.e., inhalation and exhalation)
Mechanism of breathing
Describe 3 types of pressure and pneumothorax
- Atmospheric pressure is the pressure of air around us (760 mm Hg). Intrapleural pressure is the pressure within the potential pleural space between the parietal pleura and visceral pleura (756 mm Hg). Intrapulmonic pressure is the pressure within the bronchial tree and alveoli (fluctuates higher and lower as we breathe)
- Pneumothorax: the presence of air in the pleural space, which causes collapse of the lung on that side. Recall that the pleural space is only a potential space because the serous fluid keeps the pleural membranes adhering to one another, and the intrapleural pressure is always slightly below atmospheric pressure.
Mechanism of breathing
Describe the Inhalation (inspiration) steps
Motor impulses from the medulla travel along the phrenic nerves to the diaphragm and along the intercostal nerves to the external intercostal muscles > The diaphragm contracts, moves downward, and expands the chest cavity from top to bottom > The external intercostal muscles pull the ribs up and out, which expands the chest cavity from side to side and front to back > As the chest cavity is expanded, the parietal pleura expands with it > Intrapleural pressure becomes even more negative as a sort of suction is created between the pleural membranes > The adhesion created by the serous fluid, however, permits the visceral pleura to be expanded, too, and this expands the lungs as well > As the lungs expand, intrapulmonic pressure falls below atmospheric pressure, and air enters the nose and travels through the respiratory passages to the alveoli > Entry of air continues until intrapulmonic pressure is equal to atmospheric pressure; this is normal inhalation
Mechanism of breathing
Describe the Exhalation steps and what Emphysema is
- Exhalation: Inhalation is an active process that required muscle contraction, but normal exhalation is a passive process, with relaxation of muscles.
- Emphysema: a form of chronic obstructive pulmonary disease (COPD), is a degenerative disease in which the alveoli lose their elasticity and cannot recoil (making it hard to exhale).
Pulmonary volumes (lung capacity):
List and describe 6 types of pulmonary volumes
- Tidal volume - the amount of air involved in one normal inhalation and exhalation
- Minute respiratory volume - the amount of air inhaled and exhaled in 1 minutes
- Inspiratory reserve - the amount of air, beyond tidal volume, that can be taken in with the deepest possible inhalation
- Expiratory reserve - the amount of air, beyond tidal volume, that can be expelled with the most forceful exhalation
- Vital capacity - the amount of air involved in the deepest inhalation followed by the most forceful exhalation
- Residual air (volume) - the amount of air that remains in the lungs after the most forceful exhalation. Important to ensure that there is some air in the lungs at all times, so that exchange of gasses is a continuous process, even between breaths.
Pulmonary volumes (lung capacity):
What is Forced expiratory volume (FEV)
Measured to diagnose emphysema. Deep exhalation, rapid/forceful exhalation with volume measured at 1, 2, and 3 second intervals. Any widespread damage to alveoli will decrease the FEV.
Pulmonary volumes (lung capacity):
Define: Alveolar ventilation; Anatomic dead space; Physiological dead space; and Compliance
- Alveolar ventilation - the amount of air that actually reaches alveoli and participates in gas exchange. The remaining air still within the respiratory passages is called anatomic dead space, and is normal. Physiological dead space is not normal and is the volume of non-functioning alveoli that decrease gas exchange - caused by bronchitis, pneumonia, tuberculosis, emphysema, asthma, pulmonary edema, and a collapsed lung.
- The compliance of the thoracic wall and the lungs, that is, their normal expansibility, is necessary for sufficient alveolar ventilation. Lung compliance, the natural expansibility of healthy air-filled lungs, will be decreased by any condition that increases physiological dead space.
Exchange of Gases
Describe: Partial pressure; Pulmonary edema; Pneumonia
- The partial pressure of gas is the pressure it exerts within a mixture of gasses. Because partial pressure reflects concentration, a gas will diffuse from an area of higher partial pressure to an area of lower partial pressure. Disorders of gas exchange often involve the lungs, that is, external respiration (e.g., pulmonary edema and pneumonia
- Pulmonary edema: accumulation of fluid in the alveoli. Most often caused by congestive heart failure where the left side of the heart doesn’t pump efficiently > doesn’t fully empty > blood flow backs up into veins and capillaries > as capillaries filter blood, tissue builds up in the alveoli > poor gas exchange in alveoli > dyspnea (shortness of breath) - treat by improving heart pump.
- Pneumonia: an infection of the lung. Alveolar cells secrete fluid in response to bacteria, which accumulates in their sacs + neutrophils accumulate as they try to destroy the bacteria > alveoli become too filled with crap (consolidation) which decreases gas exchange.
