Resp_L02_Flashcards
What are the three key factors that control respiration? Which is most important?
PCO2 (most important), PO2, pH.
Describe the pathway by which PCO2, PO2, and pH influence respiration.
PCO2/PO2/pH –> peripheral chemoreceptors –> sensory integration in brain –> central pattern generators (CNS respiratory centers) –> spinal cord/CN VII, IX, X, XI, XII –> respiratory muscles.
What is the accessory pathway by which PCO2 can affect respiration?
PCO2 can directly influence central chemoreceptors which then influence central pattern generators (CNS respiratory centers).
True or false: respiration is directly influened by rate of metabolism.
TRUE
What are the components of the conducting airways?
Trachea, bronchi, and bronchioles up to generation 16 or 17.
What are the components of the respiratory airways/alveolar air spaces?
Bronchioles of generation 16 or 17 to alveoli.
Smooth muscle is a major target for drugs/treatments in the respiratory system. Where is smooth msucle primarily located in the respiratory tree?
Bronchioles
What is anatomic dead space? What does this term signify?
Anatomic dead space comprises of the respiratory tree outside the alveolar air spaces (trachea, bronchi, and up to 16th/17th generation of bronchioles). No gas exchange can occur here.
Where does resistance to airflow mainly come from in the respiratory tree?
Bronchi and bronchioles.
What is the largest contributing characteristic to airway resistance? How is it related to resistance?
Radius of the airway; inversely related.
What type of drugs should particularly be avoided in patients with asthma because they result in M3 activation and reduction of airway size?
Muscarinic agonists
How do sympathetic activators affect airway size? What are two examples of drugs that can be used for this affect?
Decrease resistance by increasing airway radius. Epinephrine & albuterol
What are the 6 components of the respiratory membrane?
Lumen of alveolus to lumen of capillary: fluid lining alveolus, alveolar epithelium, epithelial basement membrane, interstitial space, capillary basement membrane, and capillary endothelial membrane.
What is the function of fibroblasts in the lung interstitium?
Produce collagen and elastin (impart distensibility and elastic recoil of lungs).
What are 3 variable factors that influence gas diffusion across respiratory membrane?
Delta-P: difference in partial pressure of gas between alveoli and blood; A: surface area available for gas diffusion; d: membrane thickness.
What type of capillaries does parietal pleura contain? Do these capillaries produce pleural fluid under normal conditions?
Systemic capillaries; yes.
What type of capillaries does visceral pleura contain? Do these capillaries produce pleural fluid under normal conditions?
Pulmonary capillaries; no.
How is pleural fluid drained from the interpleural space?
Through stoma (openings into lymphatic channels) located in parietal pleura.
What happens when pulmonary capillaries start leaking fluid?
Pleural effusion
What are the two most common reasons for pleural effusion?
Congestive heart failure (most common) and decreased microvascular oncotic pressure (leads to systemic edema).
What is the problem with the lungs in restrictive pulmonary disorders?
Decreased expansion of lungs.
What are the two main factors that determine lung compliance?
Elastic forces of lung tissue (elastin and collagen) and factors influencing surface tension (such as excess fluid accumulation).
How compliant is pulmonary vasculature? Why is this significant?
Highly compliant; need to accommodate entire cardiac output.
What is the physiological shunt of the pulmonary system?
Bronchial circulation (blood to lung tissue itself) does not get oxygenated before mixing with blood in pulmonary veins; this constitutes ~1 - 2% of CO and leads to a decrease in PO2 in pulmonary veins from 100 to ~98.
