Chapter 20_1 flashcards
(43 cards)
Upper Respiratory Tract: Functions
Conducts air to lower airways, protects lungs from foreign matter, warms, filters, and humidifies air. [Text]
Lower Respiratory Tract: Function
Participates in gas exchange by oxygenating blood and excreting carbon dioxide at the alveoli. [Text]
Lung Anatomy: Lobes
Left Lung: Two lobes (upper and lower). Right Lung: Three lobes (upper, middle, and lower). [Text, source: 3]
Pulmonary Aspiration: Risk in Right Lung
The right bronchus is more vertical and wider than the left, providing a straighter path, increasing susceptibility of aspiration into the right middle and lower lobes. [Text, source: 4]
Mucociliary Apparatus: Structure & Function
Located in bronchioles; consists of ciliated pseudostratified columnar epithelial cells and goblet cells (secrete mucus). Wavelike cilia motion moves mucus and trapped inhaled particles (dust, pollen, pathogens) upward to be swallowed or expelled. [Text, source: 5]
Factors Affecting Mucociliary Apparatus
Respiratory infections and smoking can damage or paralyze it, increasing infection risk. [Text, source: 5]
Normal Flora: Respiratory Tract
Upper respiratory tract (mouth, nose, throat) is colonized with normal flora. Lower respiratory tract and alveoli do NOT have normal flora (kept clear by mucociliary apparatus). [Text, source: 6]
Gas Exchange: Location & Process
Occurs within respiratory bronchioles, alveolar ducts, and alveoli. Oxygen moves from alveoli into pulmonary capillaries; carbon dioxide moves from capillaries into alveoli for exhalation. [Text, source: 7]
Oxyhemoglobin (HbO2): Definition
Hemoglobin with oxygen attached. Each Hgb molecule can carry four oxygen molecules. [Text, source: 8]
SaO2 (Oxygen Saturation): Definition & Measurement
Percentage of saturation of hemoglobin with oxygen. Measured with a pulse oximeter. Dependent on PaO2. [Text, source: 8]
Oxyhemoglobin Dissociation Curve: General Concept
Represents the relationship between the partial pressure of oxygen in arterial blood (PaO2) and the percentage of saturation of oxygen in the blood (SaO2). Shows Hgb’s affinity for O2 at different PaO2 levels. [Text, source: 9]
Oxyhemoglobin Dissociation Curve: Shift to the Right
Hgb has LESS affinity for O2 (releases O2 more easily to tissues). Occurs in hyperthermia (fever), acidosis (low pH), and high PCO2. [Text, source: 9]
Oxyhemoglobin Dissociation Curve: Shift to the Left
Hgb has GREATER affinity for O2 (holds O2 more tightly). Occurs in hypothermia, alkalosis (high pH), and low PCO2. [Text, source: 9]
Erythropoietin (EPO) & Hypoxia
Hypoxemia (low oxygen levels in bloodstream) is the stimulus for EPO release by the kidneys. EPO stimulates bone marrow to produce RBCs to compensate for hypoxia. [Text, source: 10]
Diaphragm: Function & Innervation
Muscle separating thoracic and abdominal cavities. Moves downward on inspiration (lung expansion), upward on expiration (lung compression). Innervated by phrenic nerve (originates at C4). [Text, source: 11]
Significance of Spinal Cord Injury at C4 or Above
Causes motor and sensory conduction to the diaphragm to be interrupted, leading to respiratory cessation; patient requires respiratory support. [Text, source: 11]
Accessory Respiratory Muscles & Retractions
External/internal intercostals, sternocleidomastoids. Retractions: Visible indentation of intercostal/supraclavicular spaces, indicating increased work of breathing and use of accessory muscles. [Text, source: 12]
Ventilation vs. Perfusion
Ventilation (V): Process of inspiration and expiration of air through pulmonary airways. Perfusion (Q): Movement of blood through pulmonary circulation, providing oxygen to the body. [Text, source: 13]
Ventilation-Perfusion Ratio (V-Q Ratio)
Ratio of air reaching alveoli to amount of blood reaching alveoli. Ideal: V and Q are matched. Measured with V-Q scan. [Text, source: 13]
V-Q Mismatch: Shunt vs. Dead Space
Occurs when air cannot flow into an alveolus or blood flow around an alveolus is altered. Shunt: Area with no ventilation. Dead space: Area with no perfusion. [Text, source: 14]
Pulmonary Embolism (PE) as Cause of V-Q Mismatch
A blood clot in the lung prevents blood flow to the alveolus, hindering gas exchange. [Text, source: 14]
Hypoxia & Pulmonary Vasoconstriction
Hypoxia stimulates pulmonary arterial vasoconstriction. Chronic hypoxia (e.g., in COPD) can lead to chronic pulmonary vasoconstriction, then pulmonary hypertension, increasing workload on the right ventricle. [Text, source: 15]
Control of Breathing: Central Chemoreceptors
Located in the medulla. Sense changes in CO2 and blood pH. Hypercapnia (high CO2) or acidosis (low pH) stimulate increased ventilation. [Text, source: 16]
Control of Breathing: Peripheral Chemoreceptors
Located in aorta and carotid arteries. Respond primarily to decreased arterial oxygen (PaO2). Stimulate breathing via hypoxic drive. [Text, source: 16]
