Respiratory System Flashcards
Describe anatomical differences between the lungs.
The right lung is larger and contains three lobes (superior, middle, and inferior lobes). The left lung is smaller because the heart occupies part of the left thoracic cavity. The left lung has only two lobes (superior and inferior).
Identify the pathway an air molecule takes after being inhaled through the nose/mouth.
An air molecule travels through the pharynx (oropharynx), through the larynx (voice box), into the trachea. The air molecule then passes through either the right or left primary bronchi, to the secondary bronchi, to the tertiary bronchi (each getting smaller in diameter). Once past the tertiary bronchi, the air molecule passes through the bronchioles before ending at the alveoli. It is at the alveoli where oxygen is unloaded (into the blood) and carbon dioxide is loaded (back into the respiratory system for excretion).
How does gas exchange occur at the alveolar level?
Gas exchange happens through diffusion as a result of differing partial pressure of oxygen in the blood versus in the alveolus AND partial pressure of carbon dioxide in the blood versus the alveolus.
Describe the functions of the diaphragm.
The diaphragm is the primary muscle used in conducting air flow. When the diaphragm contracts it becomes flattened drawing air into the lungs (inhalation). When the diaphragm relaxes, it returns to a dome shape forcing air out of the lungs (exhalation).
Other muscles involved in inspiration include scalenes, external intercostals, pectorals minor, sternocleidomastoid, and erector spine.
Muscles involved in forced expiration are the internal intercostal muscles and contracting abdominal muscles.
Provide a few instances in which air moves in and out of the nose/mouth and is considered non-respiratory.
Speaking, yawning, sneezing, coughing, and the valsalva maneuver.
What factors can affect gas exchange?
Gas exchange is affected by concentration gradients (i.e., the amount of each gas in the blood versus the alveolus).
The thickness and surface area of the alveolar membrane.
Oxygen is transported via the blood (specifically bound to hemoglobin on erythrocytes). What is the normal arterial concentration of oxygen on erythrocytes?
Approximately 98.5% of oxygen is bound to hemoglobin and approximately 1.5% is dissolved in the matrix.
List functions of the nose.
The nose warms, cleans/filters, and moistens inhaled air. It also is responsible for detecting odors and in assisting with voice amplification.
Describe the ways carbon dioxide is transported.
90% of CO2 is transported as carbonic acid. 5% is transported as carbaminohemoglobin and 5% is transported as dissolved gas in the blood.
An individual experiencing hypoxia is experiencing a lack of oxygen; this can be due to various reasons. List 2-3 reasons hypoxia may occur.
Hypoxia can occur due to:
1. inadequate pulmonary gas exchange; known as hyperemic hypoxia
2. inadequate circulation; known as ischemic hypoxia
3. anemia; known as anemic hypoxia
4. metabolic poisoning; known as histotoxic hypoxia
An individual showing signs of cyanosis (or blueness of skin) might be suffering from any of these conditions related to hypoxia.
How can smoking be associated with chronic obstructive pulmonary diseases?
Smoking can cause the cilia lining the bronchioles to decrease in function and/or decrease in number. This, in turn, causes an increase in mucous; an increase in mucous and the inability to move it, causes the bronchioles to become inflamed. Also known as chronic bronchitis.
Smoking can also cause alveolar membranes to breakdown and/or become scarred. This causes a decrease in surface area available to allow the diffusion of gasses to take place. Further, lung tissue becomes less elastic and more fibrotic. In this case, this pathology is known as emphysema.
Describe the difference between tidal respiratory volume and total lung capacity.
Tidal respiratory volume is the amount of air inhaled and exhaled during a normal non-forced breath. Total lung capacity is the amount of air that occupies the lungs during one forced inhalation and forced exhalation.
