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Gas exchange - Coggle Diagram

- - - - Acidosis
      - Fever
      - Hypercapnia
      - Increased oxygen unloading to tissues
    - - Alkalosis
      - Hypothermia
      - Increased oxygen affinity
  - - - ↓ haemoglobin
      - ↓ oxygen carrying capacity
      - ↓ oxygen delivery despite normal SpO₂
- - - - Increased PaCO₂
      - Changes in pH
  - - - Suppresses respiratory centre
      - ↓ respiratory drive
      - Hypoventilation
      - ↑ PaCO₂
    - - Bradypnoea
      - Reduced GCS
      - Respiratory acidosis
      - Hypercapnia
  - - - Carotid bodies
      - Aortic bodies
    - - ↓ PaO₂
      - ↑ PaCO₂
      - ↓ pH
    - - Hypoxaemia
        
        Stimulates respiratory rate (RR)
        
        Increased work of breathing
    - - Tachypnoea
      - Dyspnoea
      - Low SpO₂
      - Accessory muscle use
- - - - Nasal hairs trap particles
      - Filters dust and microorganisms
      - Rich blood supply warms air
    - - Passageway for airflow
      - Connects upper airway to larynx
    - - Maintains airway patency
      - Epiglottis prevents aspiration
      - Protects lower airway
    - - Boyle’s Law
        
        Pressure inversely proportional to volume
        
        Inspiration:
        
        Thoracic volume ↑
        
        Intrapulmonary pressure ↓
        
        Air enters lungs
        
        Expiration:
        
        Thoracic volume ↓
        
        Pressure ↑
        
        Air exits lungs
        
        Clinical Examples
        
        Upper airway obstruction → stridor
        
        Laryngeal oedema → respiratory distress
        
        Smoking damages cilia → infection risk
        
        Reduced GCS → aspiration risk
        
        Assessment Findings
        
        Stridor
        
        Increased work of breathing
        
        Accessory muscle use
        
        Tachypnoea
        
        Reduced SpO₂
        
        Cyanosis
        
        Abnormal breath sounds
        
        Gas Exchange
        
        Effective upper airway function supports ventilation
        
        Ventilation allows oxygen delivery to alveoli
        
        Supports normal oxygen and carbon dioxide exchange
    - - Nasal Cavity
        
        Mucus humidifies air
        
        Cilia move trapped particles upward
        
        Supports mucociliary clearance
  - - - Trachea
        
        Main airway conducting air to bronchi
        
        Supported by cartilage rings to maintain airway patency
        
        Lined with ciliated epithelium
    - - Divide airflow into right and left lungs
      - Continue mucociliary clearance
      - Contain smooth muscle that regulates airway diameter
    - - Small conducting airways
      - Major site of airway resistance
      - Smooth muscle controls bronchoconstriction and bronchodilation
      - Deliver air to alveoli
    - - Boyle’s Law
        
        Inspiration:
        
        Thoracic volume ↑
        
        Pressure ↓
        
        Air moves into lower airways
        
        Expiration:
        
        Thoracic volume ↓
        
        Pressure ↑
        
        Air exits lungs
        
        Clinical Examples
        
        Asthma → bronchoconstriction → wheeze
        
        COPD → airway narrowing and mucus production
        
        Bronchitis → inflammation and mucus accumulation
        
        Smoking → impaired ciliary function
        
        Assessment Findings
        
        Wheeze
        
        Crackles
        
        Increased respiratory rate
        
        Increased work of breathing
        
        Reduced air entry
        
        Prolonged expiration
        
        Hypoxaemia
        
        Elevated PaCO₂ in severe obstruction
  - - - Type I pneumocytes
        
        Thin cells for gas diffusion
      - Type II pneumocytes
        
        Produce surfactant
        
        Surfactant Function
        
        Reduces surface tension
        
        Prevents alveolar collapse during expiration
        
        Improves lung compliance
        
        Reduces work of breathing
        
        Physiology of Alveoli
        
        Oxygen diffuses from alveoli into blood
        
        Carbon dioxide diffuses from blood into alveoli
        
        Adequate ventilation
        
        Adequate perfusion
        
        Intact alveolar membrane
        
        Pressure gradient
        
        Ventilation-Perfusion Relationship (V/Q)
        
        Ventilation delivers oxygen to alveoli
        
        Perfusion delivers blood to alveoli
        
        Normal V/Q ratio ≈ 0.8
        
        Matching required for effective gas exchange
        
        Physiological Laws
        
        Fick’s Law
        
        2 more items...
        
        Dalton’s Law
        
        3 more items...
        
        Henry’s Law
        
        2 more items...
        
        Laplace’s Law
        
        2 more items...
        
        Clinical Examples
        
        Pulmonary oedema
        
        1 more item...
        
        ARDS
        
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        Pulmonary fibrosis
        
        1 more item...
        
        Neonatal respiratory distress syndrome
        
        1 more item...
        
        Assessment Findings
        
        7 more items...
        
        Prevent alveolar collapse
      - Alveolar-capillary membrane
        
        Thin membrane allowing rapid diffusion
  - - - Gas Exchange Process
        
        Oxygen:
        
        Alveoli → pulmonary capillary blood
        
        Carbon dioxide:
        
        Pulmonary capillary blood → alveoli
        
        Occurs across alveolar-capillary membrane
      - Perfusion
        
        Blood flow through pulmonary capillaries
        
        Requires adequate cardiac output
        
        Essential for oxygen delivery to tissues
      - Ventilation-Perfusion (V/Q) Relationship
        
        Ventilation supplies oxygen to alveoli
        
        Perfusion supplies blood to alveoli
        
        Effective gas exchange requires matching of both
      - Physiological Laws
        
        Fick’s Law
        
        Gas diffusion depends on:
        
        Surface area
        
        Membrane thickness
        
        Pressure gradient
        
        Large capillary surface area improves diffusion
        
        Dalton’s Law
        
        Gases move according to partial pressure gradients
        
        Oxygen moves from high alveolar PO₂ to lower capillary PO₂
        
        Carbon dioxide moves from blood to alveoli
        
        Henry’s Law
        
        Amount of gas dissolved in blood proportional to pressure
        
        Explains oxygen dissolved in plasma
        
        Clinical Examples
        
        Pulmonary embolism
        
        Reduced perfusion to alveoli
        
        High V/Q mismatch
        
        Pulmonary hypertension
        
        Increased pulmonary vascular resistance
        
        Shock
        
        Reduced pulmonary perfusion
        
        ARDS
        
        Damage to alveolar-capillary membrane
        
        Assessment Findings
        
        Hypoxaemia
        
        Tachypnoea
        
        Cyanosis
        
        Reduced PaO₂
        
        Increased work of breathing
        
        Elevated lactate in poor perfusion states
- - - - COPD
        
        CO₂ retention
        
        Hypercapnia
        
        Respiratory acidosis
    - - Elevated PaCO₂
      - Drowsiness
      - Headache
      - Confusion
      - Reduced respiratory drive in severe hypercapnia
- - - - Alveoli → pulmonary capillary blood
  - - - Pulmonary capillary blood → alveoli