Respiratory

• Purpose and General Function

  • Transport of oxygen from air to blood
  • Removal of carbon dioxide from the blood
• Two anatomical areas


  • Upper respiratory tract
  • Lower respiratory tract
• Upper respiratory tract


  • Nasal cavity - Warming and moistening of air, Foreign material trapped by mucous secretions
  • Nasopharynx - Pharyngeal tonsils in posterior wall
  • Palatine tonsils - Lymphoid tissue in posterior portion of the oral cavity
  • Oropharynx - Common passage for air and food, Epiglottis protects opening into larynx, Closes over glottis at swallowing to prevent aspiration
  • Larynx - Two pairs of vocal cords
  • Trachea - Lined by pseudostratified ciliated epithelium, C-shaped rings of cartilage
• Lower respiratory tract


  • Bronchial tree - Continuous branching, Trachea branches into right and left primary bronchi, secondary bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveoli - Lined by simple squamous epithelium and surfactant to reduce surface tension and maintain inflation
  • End point for inspired air
  • Site of gas exchange
• Ventilation


  1. Inspiration - Air moves from atmosphere into lungs

  2. Expiration - Air moves from lungs into atmosphere
• Pulmonary volumes


  • Tidal volume - Amount of air exchanged with quiet inspiration and expiration
  • Residual volume - Volume of air remaining in lungs after maximum respiration
  • Vital capacity - Maximal amount of air that can be moved in and out of the lungs with a single forced inspiration and expiration
• Hypercapnia


  Carbon dioxide levels in the blood increase, Carbon dioxide easily diffuses into CSF, Lowers pH and stimulates respiratory center, Increased rate and depth of respirations (hyperventilation), Causes respiratory acidosis - Nervous system depression
• Hypocapnia


  Caused by low carbon dioxide concentration (low partial pressure of carbon dioxide) in blood, May be caused by hyperventilation, Excessive amounts of carbon dioxide expired, Causes respiratory alkalosis
• Gas exchange


  Flow of gases between the alveolar air and blood (external respiration), Gas exchange depends on the relative concentrations (partial pressures) of the gases, Po2 - Partial pressure of oxygen, Pco2 - Partial pressure of carbon dioxide, Each gas in a mixture moves along its partial pressure gradient, independent of other gases (Dalton law)
• Factors affecting diffusion of gases

  • Partial pressure gradient
  • Thickness of the respiratory membrane, Fluid accumulation in alveoli or interstitial tissue impairs gas exchange
  • Total surface area available for diffusion, If part of alveolar wall is destroyed, surface area is reduced, so less exchange
• Diagnostic tests


  • Spirometry - Pulmonary function test (PFT)
  • Arterial blood gas determination
  • Oximetry - Measures O2 saturation
  • Exercise tolerance testing
  • Radiography
  • Bronchoscopy
  • Sputum testing
• General manifestations of respiratory disease

  • Sneezing - Reflex response to irritation in upper respiratory tract, Assists in removing irritant, Associated with inflammation or foreign material
  • Coughing - Irritation caused by nasal discharge, Inflammation or foreign material in lower respiratory tract, Caused by inhaled irritants
  • Sputum - Yellowish-green, cloudy, thick mucus, Often indication of a bacterial infection, Hemoptysis - Blood-tinged (bright red) frothy sputum, usually associated with pulmonary edema
  • Breathing patterns and characteristics - Eupnea (normal rate), Kussmaul respirations (deep rapid respirations - typical for acidosis), Labored respiration or prolonged inspiration or expiration (often associated with obstruction of airways), Wheezing or whistling sounds (indicate obstruction in small airways), Stridor (high-pitched crowing noise - usually indicates upper airway obstruction)
• Bronchiectasis


  A long-term condition where the airways of the lungs become widened, leading to a build-up of excess mucus that can make the lungs more vulnerable to infection
• Respiratory tract infections


  • Upper respiratory tract infections
  • Lower respiratory tract infections
• Upper respiratory tract infections

  • Common Cold - Viral infection, More than 200 possible causative agents, Spread through respiratory droplets, Handwashing and respiratory hygiene important in prevention, Symptomatic treatment, Secondary bacterial infections may occur
  • Sinusitis - Usually bacterial infection, Analgesics for headache and pain, Course of antibiotics often required to eradicate infection
  • Laryngotracheobronchitis (croup) - Common viral infection, particularly in children, Common causative organisms - Parainfluenza viruses and adenoviruses, Infection usually self-limited
  • Epiglottitis - Acute infection, Common in children ages 3 to 7 years, Usually caused by Haemophilus influenzae type B, Rapid onset, fever and sore throat, Drooling and difficulty swallowing
  • Influenza (Flu) - Viral infection, Three groups of influenza viruses - Type A (most prevalent), types B and C, Viruses constantly mutate, Sudden, acute onset with fever, marked fatigue, aching pain in the body, May also cause viral pneumonia, Mild case of influenza may be complicated by secondary bacterial pneumonia, Commonly, deaths in flu epidemics result from pneumonia
  • Scarlet Fever - Bacterial illness that mainly affects children, Causes a distinctive pink-red rash, Caused by group A β-hemolytic Streptococcus (S. pyogenes), Symptoms - Typical "strawberry" tongue, Fever, sore throat, Chills, vomiting, abdominal pain, malaise, Treatment - Antibiotics
• Lower respiratory tract infections


  • Bronchiolitis - Caused by the respiratory syncytial virus (RSV), Transmitted by oral droplet, Virus causes necrosis, inflammation in small bronchi and bronchioles, Signs - Wheezing and dyspnea, rapid shallow respirations, cough, rales, chest retractions, fever, malaise, Treatment - Supportive and symptomatic
  • Pneumonia - Classification based on causative agent, anatomical location, pathophysiologic changes, epidemiologic data
  • Severe Acute Respiratory Syndrome (ARDS) - Acute respiratory infection, Causative microbe - SARS-associated coronavirus (Covid 19= SARS-Cov2), Transmission by respiratory droplets - close contact, First signs - Fever, headache, anorexia, possibly diarrhea, Later signs - Effect on lungs evident - dry cough, marked dyspnea, areas of interstitial congestion, hypoxia, mechanical ventilation may be required, High fatality rate, Risk factors - Travel to endemic or epidemic area, Close contact with an infected traveler
  • Tuberculosis - Disease caused by germs that are spread from person to person through the air, Usually affects the lungs, but can also affect other parts of the body, Caused by Mycobacterium tuberculosis, Occurs more frequently with people living in crowded conditions, immunodeficiency, malnutrition, alcoholism, HIV infection, chronic disease, conditions of war (example of Gaza, Palestine), Primary infection is asymptomatic, Secondary or re-infection with TB occurs when cell-mediated immunity is impaired, Signs and symptoms - Anorexia, malaise, fatigue, weight loss, afternoon low-grade fever and night sweats, prolonged cough becoming increasingly severe and productive, sputum becomes purulent
• 62 percent of homes destroyed
• 75,000 tonnes of explosives have been dropped on Gaza
• 1.1 million people facing 'catastrophic' lack of food
• 1.09 million people have been infected with diseases
• 26 hospitals destroyed and hundreds of medics killed
• Absence of food, water, Hospital, medication
• Mycobacterium tuberculosis


  Usual cause of tuberculosis
• Tuberculosis


  • Somewhat resistant to drying and many disinfectants
  • Can survive in dried sputum for weeks
  • Destroyed by ultraviolet light, heat, alcohol, 45
• Primary infection


  1. Primary infection is asymptomatic

  2. When organism first enters the lungs

  3. Engulfed by macrophages—local inflammation

  4. If cell-mediated immunity is inadequate, mycobacteria reproduce and begin to destroy lung tissue

  5. This form of disease is contagious!
• Secondary or re-infection with TB

  1. Occurs when client's cell-mediated immunity is impaired because of: Stress, Malnutrition, HIV infection, Age

  2. Mycobacteria begin to reproduce and infect lung

  3. Active TB, which can be spread to others!
• Secondary or active stage

  • Anorexia
  • Malaise
  • Fatigue
  • Weight loss
  • Afternoon low-grade fever and night sweats develop
  • Cough is prolonged and becomes increasingly severe and, as cavitation develops, more productive
  • Sputum becomes purulent and often contains blood
• If cell-mediated immunity is adequate

  1. Some bacilli migrate to lymph nodes

  2. Granuloma—formation of tubercle (contains live bacilli)—tubercle may be visible on chest radiograph

  3. Bacilli may remain viable in a dormant stage for years
• Tuberculin (skin) test


  Indicates first exposure or primary infection
• Active infections


  Indicated by chest radiograph, sputum culture and sensitivity
• Treatment


  1. Long-term treatment with a combination of drugs

  2. Length of treatment varies from 6 to 12 months
• Effective treatment


  • Requires monitoring and follow-up and is expensive
  • TB is becoming an increasingly serious problem because of: Homelessness and crowding in shelters, HIV infection, Lack of health care, Multidrug resistant TB
• Histoplasmosis


  • Fungal infection caused by Histoplasma capsulatum
  • Spores can be inhaled on dust particles
  • Common opportunistic infection
  • First stage often asymptomatic
  • Second stage: Granuloma formation and necrosis, Cough, fatigue, fever, night sweats
  • Treatment—antifungal agents
• Granuloma


  An aggregation of macrophages that forms in response to chronic inflammation
• Anthrax


  • Bacterial infection by gram-positive bacilli
  • Spores can be viable for long periods of time
  • Skin, respiratory, or digestive tract
  • Cutaneous form, Inhalation form, Gastrointestinal form
• Obstructive Lung Diseases


  • Cystic Fibrosis
  • Lung Cancer
  • Obstructive Sleep Apnea
  • Asthma
• Cystic Fibrosis


  • Inherited (genetic) disorder
  • Gene located on chromosome 7
  • Tenacious mucus from exocrine glands
  • Primary effects seen in lungs and pancreas
  • Lungs: Mucus obstructs airflow in bronchioles and small bronchi, Permanent damage to bronchial walls
• Lung Cancer


  • About 90% of cases are related to smoking
  • Bronchogenic carcinoma: Most common type of primary malignant lung tumor, Arises from bronchial epithelium
  • Squamous cell carcinoma (NSCLC): Usually develops from epithelial lining of a bronchus
  • Adenocarcinomas and bronchoalveolar cell carcinomas: Usually found on periphery of lung
• Types of Lung Cancer

  • Non small cell carcinoma (NSCLC) (80-85%)
  • Small cell carcinoma (15-20%)
• Small cell carcinoma


  • Commonly seen among heavy smokers
  • Grows and spreads faster then (NSCLC)
  • Responds better to chemotherapy
  • In most cases diagnosis is done after metastasis
  • Common sites of metastasis is other lung, lymph node, liver, bone and brain