Respiratory
Mechanics, volumes, ventilation/perfusion, gas transport and the control of breathing.
34 pages
Exam priority: high
- CO₂ transport and the Haldane effectMechanism · CO₂ travels in blood mostly as bicarbonate
- Control of breathing, chemoreceptors and lung reflexesRegulation · The brainstem sets the rhythm of breathing
- Dead space and alveolar ventilationConcept · Part of every breath stays in the airway tubes and never reaches the alveoli
- Lung volumes, capacities and spirometryMeasurement · The lung has four basic volumes; their sums are the capacities
- Mechanics of breathing: pressures and musclesMechanism · To breathe in, muscles enlarge the chest, pressure inside the lungs drops and air flows in by…
- Obstructive and restrictive patterns, and flow–volume loopsMeasurement · In obstruction the air comes out slowly; in restriction the lung is small
- Oxygen transport and the dissociation curveMechanism · Almost all oxygen rides bound to hemoglobin
- Oxygenation: SpO₂, PaO₂, cyanosis and oxygen therapyMeasurement · A pulse oximeter shows how full of O₂ hemoglobin is; a blood gas measures O₂ pressure
- The alveolar gas equation and the A–a gradientMeasurement · A formula estimates how much oxygen is in the alveoli
- The causes of hypoxemiaMechanism · There are only a few ways to end up with too little oxygen in the blood
- Types of hypoxia and what hypoxia does to the bodyTable to know · Hypoxia means cells get too little oxygen
- Ventilation–perfusion matching and West zonesMechanism · To exchange gas, air and blood must reach the same alveolus
Exam priority: medium
- Abnormal breathing patterns and sleep apneaRegulation · How someone breathes says a lot: cycles that swell and fade, deep breaths from acid, or pauses…
- Airway resistanceConcept · The narrower a tube, the harder it is to push air through
- Alveolar air: composition, slow renewal and how ventilation sets PAO₂ and PACO₂Concept · The air deep in the lungs is not fresh air
- Carbon monoxide, methemoglobin and cyanideMechanism · Three poisons starve tissues of oxygen even when the lungs work: two spoil hemoglobin and one…
- Diffusion across the respiratory membrane and DLCOMechanism · Oxygen crosses from the air sac into the blood through a very thin wall
- Gas laws of breathing: partial pressure, solubility and water vapourConcept · Each gas in air pushes with its own share of the pressure
- Hypercapnia and dyspnea: what excess CO₂ does and why breathlessness is feltMechanism · Too much CO₂ makes the blood acid and, at high levels, sedates the brain
- Hypoxemic and hypercapnic respiratory failureMechanism · The lungs can fail in two ways: they can't get oxygen into the blood (type 1), or they can't…
- Lung and chest wall complianceConcept · Compliance is how much the lung inflates for each unit of pressure
- Oxygen at the tissue level: interstitial and cellular PO₂Mechanism · Oxygen steps down from blood to tissue fluid to cells
- Oxygen content, delivery and extractionMeasurement · Tissues care not just about saturation but about how much oxygen the blood carries and how much…
- Physiology of positive-pressure ventilationMechanism · A ventilator pushes air in with positive pressure
- Physiology of pulmonary edemaMechanism · When lung capillaries leak more fluid than the lymphatics can drain, the air sacs flood and…
- Pleural fluid: formation and drainageMechanism · A tiny layer of fluid between lung and chest wall lets them glide
- Surface tension, surfactant and Laplace's lawConcept · A thin film of fluid lines the air sacs and pulls them shut
- The pulmonary circulation and hypoxic vasoconstrictionRegulation · The right heart pumps all the blood through the lungs at low pressure
- The work of breathingConcept · Breathing costs energy: the lung must be stretched and airway resistance overcome
- Ventilatory responses to CO₂, pH and O₂ and how the carotid body senses O₂Measurement · Breathing rises steeply when CO₂ goes up, less with acid and only late when O₂ falls
For completeness
- Airway defenses, cough and mucociliary clearanceConcept · The nose filters, mucus traps, cilia sweep upward and cough throws it out: that is how the lung…
- How voice is produced: phonation, articulation and resonanceMechanism · Air from the lungs makes the vocal folds vibrate; the throat, mouth and nose shape that buzz…
- The bronchial circulationConcept · The lung has two blood supplies: the pulmonary one to oxygenate blood, and the bronchial one…
- The CO₂ dissociation curve and the respiratory exchange ratioConcept · Blood carries CO₂ almost in proportion to its pressure
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Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Representative model, for educational purposes only.