respiratory system

• Functions of the respiratory system


  • Movement of air for gas exchange
  • Gas exchange between air and blood
  • Produce sounds
  • Protect respiratory surfaces from dehydration and temperature changes, and pathogenic microorganisms
  • Assist in regulation of blood volume, blood pressure and fluid pH

  
• Respiration


  1. Pulmonary ventillation (air movement)

  2. External respiration (gas exchange in lungs)

  3. Transport of gasses (circulation)

  4. Internal respiration (gas exchange at tissues)
• Upper respiratory tract


  • Oral / Nasal cavities
  • Pharynx

  
• Lower respiratory tract


  • Larynx
  • Trachea
  • Bronchi
  • Lungs
  • Bronchioles
  • Alveola

  
• Zones of the respiratory system


  • Conducting Zone (anatomical structures necessary to move air)
  • Respiratory Zone (structures necessary for gas exchange)

  
• Respiratory epithelium


  • Pseudostratified, ciliated, columnar
  • Produce about 1 liter of mucus a day
• Nose and nasal cavity


  • Airway
  • Moistens and warms air
  • Filters air
  • Chamber for speech
  • Smell receptors
• Cartilages of the nose


  • Greater Alar (2)
  • Lateral nasal (2)
  • Lesser Alar (4)

  
• Nostril blockage may cause chronic stuffiness (nasal congestion) and a tendency to get sinus infections
• Septoplasty


  Surgery to correct a deviated nasal septum
• Rhinoplasty


  Cosmetic surgery to reshape the nose
• Popular snore aids like Breath right Strips, Oral spray lubricant, and Head positioning pillow did not show any difference in snoring amount after a week of monitoring
• Nasal sinuses


  • Frontal (4)
  • Maxillary (2)
  • Ethmoid (2)
  • Sphenoid (1)

  
• Regions of the pharynx


  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
• Structures of the larynx


  • Thyroid cartilage
  • Cricoid cartilage
  • Epiglottis
  • Arytenoid (2)
  • Corniculate (2)
  • Cuneiform (2)
  • Thyrohyoid membrane
  • Cricothyroid membrane
  • Cricotracheal membrane
• Vocal fold (vocal cord)


  Vibrates to produce sound
• Vestibular fold


  Helps close the larynx during swallowing
• Glottis


  Opening between the vocal folds
• Intrinsic laryngeal muscles


  • Interarytenoid
  • Lateral cricoarytenoid
  • Posterior cricoarytenoid
  • Cricothyroid
  • Thyroarytenoid (true vocal cord)
• Trachealis muscle


  Runs posteriorly along the trachea
• Bronchi


  • Primary
  • Secondary (Lobar) - 3 right, 2 left
  • Tertiary (segmental) - 9-10 per lung
  • Terminal bronchi
  • Respiratory bronchi (contain alveoli)
• Bronchitis


  Inflammation of the bronchi
• Asthma medications


  • Corticosteroids (reduce swelling and mucus)
  • Bronchodilators (relax bronchi muscles)
• Alveolar sacs


  Collection of alveoli

  
• Alveoli


  • Type I cells (squamous epithelium)
  • Basal lamina
  • Connective tissue
  • Type II cells (cuboid epithelium, secrete surfactant)
  • Macrophages
  • Respiratory membrane (air-blood barrier)

  
• Emphysema


  Progressive lung disease that damages air sacs and airways, obstructing airflow
• Lung lobes


  • Right lung - 3 lobes (superior, middle, inferior)
  • Left lung - 2 lobes (superior, inferior)
• Lung surfaces


  • Apex
  • Costal
  • Diaphragmatic
  • Mediastinal

  
• Structures at the root of the lung


  • Bronchi
  • Arteries (superior)
  • Veins (inferior)

  
• Pleural sac


  Surrounds each lung, with parietal pleura covering the thoracic walls and visceral pleura covering the lung tissue
• Respiratory muscles


  • Diaphragm (lowers)
  • External intercostals (elevate ribs)
  • Pectoralis minor (elevate ribs)
  • Serratus anterior (elevate ribs)
  • Internal intercostals (depress ribs)
  • Abdominal muscles (raise diaphragm)

  
• Neural pathways controlling respiration


  • Upper centers (voluntary control)
  • Pons (pneumotaxic and apneustic centers)
  • Medulla oblongata (respiratory rhythmicity center - dorsal for inspiration, ventral for expiration)
• Respiratory rate and depth can be modified by upper center control, stretch receptors in lungs, and chemoreceptors/baroreceptors

  
• Respiratory system injuries and diseases


  • Pneumothorax (collapsed lung)
  • Pulmonary thromboembolism (blood clot in pulmonary arteries)
  • Irritation of parietal pleura or diaphragm (referred pain to C3-C5 dermatomes)

  
• Lung cancers


  • Bronchogenic carcinoma
  • Small cell carcinoma (highly malignant, fatal)
  • Non-small cell carcinoma
• COPD


  Chronic Obstructive Pulmonary Disease - group of lung diseases that block airflow and make breathing difficult, mainly caused by long-term smoking
• COPD treatments focus on controlling symptoms and minimizing further damage, including oxygen therapy, inhaled/oral steroids to decrease inflammation
• Hiccups


  Spasm that contracts the diaphragm, causing a sudden intake of breath stopped by closure of the vocal cords
• Causes of hiccups


  • Very full stomach
  • Eating too much too quickly
  • Drinking too much alcohol
  • Swallowing too much air
  • Smoking
  • Sudden change in stomach temperature
  • Emotional stress or excitement