Anatomy of the Respiratory System

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Questions and Answers

What is a potential consequence of prolonged hyperventilation syndrome?

Tachycardia

Bronchospasm

Respiratory acidosis

Tetany (correct)

What characterizes pleurisy?

Stitching pain that increases with inspiration (correct)

Accumulation of pus in the pleura

Inflammation of lung tissue

Pain that decreases with inspiration

Which of the following conditions could result in dyspnea due to weakness of respiratory muscles?

Guillan Barre syndrome (correct)

Asthma

Pneumonia

Congestive heart failure

Which type of pneumonia involves patchy inflammation of both lungs?

Broncopneumonia Signup and view all the answers

What symptom is commonly associated with left-sided heart failure?

Orthopnea Signup and view all the answers

Which mechanism is primarily responsible for the removal of particles larger than 10 micrometers from the respiratory tract?

Nasal filtration Signup and view all the answers

What happens to mucociliary transport due to cigarette smoke and air pollution?

It is damaged and reduced Signup and view all the answers

Which symptom is associated with myopericarditis?

Dry cough Signup and view all the answers

Which condition could cause sudden onset dyspnea?

Acute pulmonary edema Signup and view all the answers

What is a consequence of congenital defects in mucociliary transport?

Recurrent infections Signup and view all the answers

Platypnea is characterized by breathlessness in which position?

Upright Signup and view all the answers

What is a common symptom of aortic dissection?

Sudden onset chest pain Signup and view all the answers

Which of the following is NOT a symptom of respiratory failure?

Dyspepsia Signup and view all the answers

Which of the following is a non-specific soluble factor present in lung secretions?

Antitrypsin Signup and view all the answers

What is the primary mechanism behind orthopnea?

Increased venous return Signup and view all the answers

Which of the following conditions typically does NOT produce dyspnea with normal cardiac and chest examination?

Acute pneumothorax Signup and view all the answers

What is the role of the cilia in the respiratory epithelium?

They push the mucus blanket towards the mouth Signup and view all the answers

Which cellular component is primarily responsible for producing lysozyme?

Granulocytes Signup and view all the answers

Which of the following conditions is characterized by sudden severe chest pain and is associated with smoking?

Pulmonary embolism Signup and view all the answers

What effect does sitting up have on dyspnea in patients?

Reduces respiratory muscle strain Signup and view all the answers

What is a less frequent symptom of mediastinal syndrome?

Stridor Signup and view all the answers

Which investigation method is typically used to diagnose conditions related to the respiratory system?

Plain X-ray chest Signup and view all the answers

Which symptom should be a concern for hypoxic corpulmonale?

Lower limb edema Signup and view all the answers

What is the primary function of the nose in the respiratory system?

To facilitate smell and respiration Signup and view all the answers

Which bronchus is more vertical, causing inhaled materials to more likely enter the corresponding lung?

Right main bronchus Signup and view all the answers

What is the main structural difference between bronchi and bronchioles?

Bronchi have thicker walls and cartilage, while bronchioles do not Signup and view all the answers

What does FEV1 represent in pulmonary function tests?

Forced expiratory volume in one second Signup and view all the answers

What is the total surface area provided by the alveoli in the lungs?

40-80 m² Signup and view all the answers

Which test primarily reflects large airway flow?

Peak expiratory flow rate (PEFR) Signup and view all the answers

Which type of cells line the alveoli and provide a thin barrier for gas exchange?

Type I pneumocytes Signup and view all the answers

How many lobes does the left lung have?

2 lobes Signup and view all the answers

What should a good sputum sample ideally contain?

Inflammatory cells Signup and view all the answers

Which statement about FEV1 and PEFR correlation is true?

The correlation decreases significantly in asthma Signup and view all the answers

What is the role of the pores of Kohn in the alveolar wall?

Facilitate communication between adjacent alveoli Signup and view all the answers

What components make up the pleural sac surrounding the lungs?

Visceral and parietal layers Signup and view all the answers

Which technique is used to directly visualize the tracheo-bronchial tree?

Bronchoscopy Signup and view all the answers

Which of the following is a common hematological examination finding in allergic disorders?

Eosinophilia Signup and view all the answers

What is a primary use of broncho-alveolar lavage?

For sampling bronchial cells Signup and view all the answers

What is the typical percentage of FEV1 relative to FVC in normal subjects?

75% Signup and view all the answers

What is a potential cause of positional dyspnea when a patient lies on the healthy side?

Trepopnea Signup and view all the answers

Which characteristic of sputum suggests the presence of a lung abscess or bronchiectasis?

Large volumes and purulent Signup and view all the answers

What differentiates hemoptysis from hematemesis?

Hemoptysis does not involve melena. Signup and view all the answers

Which type of cough is characterized by the absence of sputum?

Dry cough Signup and view all the answers

In which condition is pink-tinged sputum commonly observed?

Pulmonary edema Signup and view all the answers

Which of the following is a respiratory cause of hemoptysis?

Pulmonary infarction Signup and view all the answers

What does foul-smelling sputum typically suggest in a lung condition?

Anaerobic infection Signup and view all the answers

Which of the following is NOT a cause of hemoptysis?

Asthma Signup and view all the answers

Study Notes

Anatomy and Physiology of the Respiratory System

The respiratory system facilitates smell and respiration.
The nose is considered the oral cavity, the pharynx, and the larynx.
The oral cavity extends from the lips to the tonsils.
The trachea (windpipe) is 10-12 cm long and positioned slightly to the right of the midline.
The trachea divides at the carina, under the junction of the manubrium and second costal cartilage.
The right main bronchus is more vertical than the left, so inhaled material tends to end up in the right lung.
The right main bronchus divides into the upper, intermediate, middle, and lower lobe bronchus.
The left main bronchus divides into upper and lower lobe bronchus.
Lobar bronchi divide further into segmental and sub-segmental bronchi.
The first seven divisions of bronchi contain cartilage and smooth muscles, as well as epithelial linings with cilia and goblet cells.
The submucosal tissues contain mucus-secreting glands.
The next 16-18 divisions (bronchioles) progressively become thinner and have no appreciable cartilage or muscle layer.
They have a single layer of ciliated cells but few goblet cells, and include granulated Clara cells that produce a surfactant-like substance.
Bronchioles finally divide within the acinus into smaller respiratory bronchioles that have alveoli arising from the surface.
Respiratory bronchioles supply approximately 200 alveoli via alveolar ducts.
The term "small airways" refers to bronchioles of less than 2 mm in diameter.
There are approximately 300 million alveoli in each lung with a total surface area of 40-80 square meters.
Alveoli are lined mainly by type I pneumocytes with very thin cytoplasm for efficient gas exchange.
Pores of Kohn are holes in the alveolar wall facilitating communication between alveoli of adjoining lobules.
The right lung has 3 lobes (upper, middle, and lower)
The left lung has 2 lobes (upper and lower).
The lungs are enclosed in the pleural sac, which has two layers: visceral and parietal, with a thin film in between.

Defense Mechanisms of the Respiratory Tract

Physical and physiological mechanisms
- Humidification: Prevents dehydration of the epithelium.
- Particle removal: Particles larger than 10 µm are removed in nostrils and nasopharynx (e.g., pollen grains); particles 5-10 µm become impacted in the carina.
Particle expulsion: Coughing, sneezing, or gagging.
Respiratory tract secretions: Pseudostratified columnar ciliated cells line the respiratory epithelium down to small airways.
- Each cell has approximately 200 cilia that beat at 1000 beats per minute to move mucus towards the mouth.
Factors damaging mucocilliary transport: Cigarette smoke, air pollution, bacterial and viral infections.
Congenital defects in mucocilliary transport can lead to recurrent infections and bronchiectasis (immotile cilia syndrome and cystic fibrosis).
Humoral and cellular mechanisms
- Non-specific soluble factors: Antitrypsin is present in lung secretions and is derived from plasma.
- Antioxidant defenses: Superoxide dismutase and low molecular weight antioxidants (ascorbate and urate) are in the epithelial lining fluid.
- Non-specific soluble factors: Lysozyme in granulocytes, lactoferrin in epithelial cells and neutrophils, interferon (produced by cells in response to viral infection), complement (secretions derived from plasma), surfactant protein A (enhances phagocytosis by macrophages), and defensins (bactericidal peptides from neutrophils).
- Alveolar macrophages: Phagocytosis, cell killing, cytokine secretion, and immuno-regulation, are important for the immune response. They are the dominant cell type in airways (90%).
- Lymphoid tissue: Contains lymphocytes throughout the airways, contributing to local immunity through differentiation into IgA-secreting plasma cells

Major Manifestations of Lung Disease: Dyspnea

Dyspnea associated with increased work of breathing: Accessory muscles of respiration (sternomastoids and scalene) and nasal flaring in children.
Airway obstruction: Chronic bronchitis, emphysema, bronchial asthma, stridor.
Decreased pulmonary compliance (stiff lungs): Pulmonary edema, pulmonary fibrosis.
Restricted chest expansion: Kyphoscoliosis, lung resection, painful lesions (e.g., rib fracture, pleural pain), and pregnancy.
Dyspnea associated with hyperventilation: Massive pulmonary embolism (decreased perfusion of well-aerated alveoli, increased dead space), interstitial lung diseases, and pneumonia. hypoxia stimulates the respiratory center leading to hyperventilation.
Metabolic acidosis: Increased hydrogen ions stimulate the respiratory center (e.g., diabetic ketoacidosis and renal failure).
Hyperventilation syndrome: Severe and prolonged hyperventilation can lead to respiratory alkalosis, tetany, and possible epileptic fits.
Hysterical dyspnea: Associated with hyperventilation and sighing.
Dyspnea associated with weakness of respiratory muscles (decreased ventilation): Spinal cord injuries (above C4), Guillain-Barré syndrome, poliomyelitis, and myasthenia gravis.
Dyspnea of cardiac origin: Heart failure (early symptom, associated with orthopnea and paroxysmal nocturnal dyspnea (PND)), pericardial effusion, constrictive pericarditis, and acute left-sided heart failure (cardiac asthma).

Dyspnea with normal heart and chest

Anemia
Fevers (whatever the cause)
Thyrotoxicosis
Diabetic ketoacidosis
Renal failure
Hysterical dyspnea (not uncommon)

Causes of Sudden Onset Dyspnea (within minutes)

Acute pulmonary edema
Massive pulmonary embolism
Laryngeal edema or spasm
Foreign body inhalation
Pneumothorax

Positional Dyspnea

Orthopnea: Dyspnea on lying flat, relieved by sitting
Pathogenesis (lying flat): Increased venous return, increased pulmonary congestion, high position of diaphragm, compression by enlarged liver/ascites, limited chest expansion.
- Sitting up: Helps venous drainage of head and neck, decreases venous return from lower body, relieves compression of abdominal viscera on diaphragm, improves diaphragm and intercostal muscle performance.
Platypnea: Breathlessness in upright position, relieved by lying down, due to marked fall in blood oxygen saturation; causes include intracardiac shunt (ASD), pulmonary parenchymal ventilation/perfusion mismatch (COPD), pulmonary arteriovenous shunts.
Trepopnea: Dyspnea lying on one side of the body, occurring in unilateral chest disease when the affected side is down.

Major Manifestations of Lung Disease: Cough

Definition: Explosive expiration to clear the tracheobronchial tree of secretions and foreign bodies.
Types: Dry (without sputum) or productive (with sputum).

Causes of Cough

Inflammation: Bacterial or viral infections, cigarette smoking, post-nasal discharge, gastric reflux.
Mechanical: Inhalation of dust, compression, intraluminal foreign bodies, extra-luminal granuloma (tumor)
Chemical: Inhalation of irritants (e.g., gases, cigarette smoke)
Thermal: Inhalation of very hot or very cold air
Non-pulmonary causes: Heart failure, drugs (e.g., ACE inhibitors)

Expectorations

Volume: Purulent sputum or large amounts suggest lung abscess or bronchiectasis.
Changes: Postural (lung abscess), seasonal (asthma)
Color: Yellow or green, common sign of infection
Consistency: Frothy, pink-tinged sputum suggests pulmonary edema.
Odor: Foul, smelling of anaerobic infection in suppurative lung diseases.

Hemoptysis

Definition: Coughing up blood from the lower respiratory tract (blood above larynx = false hemoptysis).
Types: Blood-tinged, streaked, or frank hemoptysis.
Causes of hemoptysis:
- Respiratory causes: Infections, tumors, vascular (pulmonary infarction/embolism/vasculitis), foreign body, bronchoscopy, lung biopsy, chest trauma, pulmonary TB, pneumonia, bronchial adenoma, bronchial carcinoma, tracheal tumors, metastases
- Cardiac causes: Mitral stenosis, cardiac asthma
- General causes: Bleeding tendency, anticoagulation

Chest Pain

Analysis of chest pain: Onset, course, duration, character, site, radiation, severity, provocation, relief, frequency, special times of occurrence (associated symptoms).
Causes of chest pain:
- Cardiac: Myocardial infarction, pulmonary embolism, pericarditis, aortic dissection
- Respiratory: Acute pleurisy, pneumothorax, acute massive lung collapse
- Mediastinal: Non-cardiac chest pain (e.g. from gastro-esophageal reflux disease, esophageal spasm, mediastinitis, mediastinal tumors)
- Chest wall: Localized aching/tenderness, skin/breast abscess, rib fracture/osteomyelitis, spine as Potts disease, intercostal muscles/nerves, (e.g., Herpes zoster vesicles), some diabetics

Other Symptoms

Symptoms of Toxemia (tuberculosis): Fever, night sweats, anorexia, weight loss
Symptoms of Systemic Congestion: Dyspepsia, right hypochondrial pain, lower limb edema (hypoxic cor pulmonale).
Symptoms of Respiratory Failure: Hypoxia (fatigue, headache), hypercapnia (headache, somnolence, altered sleep rhythm, disturbed consciousness)
Symptoms of Mediastinal Syndrome: Chest pain, cough, hoarseness, dyspnea, stridor, dysphagia, Horner's syndrome
Horner's Syndrome: Ptosis (drooping eyelid), miosis (constricted pupils), anhidrosis (lack of sweating).
Herpes Zoster (shingles): Skin rash, pain

Investigations of Respiratory Disease

Imaging: Plain X-ray chest, High-resolution CT, CT-angiogram (CTA), MRI, Scintigraphic imaging (ventilation-perfusion lung scans; Gallium imaging).
Arterial Blood Gases: Measurement of partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) on arterial blood (essential for respiratory failure and severe asthma).
Pulse oximetry: Non-invasive device to estimate functional oxyhemoglobin saturation.
Respiratory function testing: Spirometry, including FEV1, FVC, FEV1/FVC ratio, Peak Expiratory Flow Rate (PEFR), tidal volume, inspiratory reserve volume, vital capacity.
Obstructive vs. restrictive lung disease: Pulmonary function tests can distinguish obstructive from restrictive lung diseases by assessing the changes in vital capacity and expiratory volume.
Biological Specimens: Sputum (Gram's stain/culture, culture for mycobacteria, fungi/viruses; immunofluorescent stain for Pneumocystis carinii in HIV patients; cytologic staining for malignant cells)
Other Procedures: Percutaneous needle aspiration (CT guided), thoracocentesis, bronchoscopy (flexible or rigid to visualize tracheo-bronchial tree), retrieval of foreign bodies.

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Description

This quiz explores the anatomy and physiology of the respiratory system. It covers key components such as the nose, pharynx, larynx, trachea, and bronchi, along with their functions in respiration and olfaction. Test your knowledge and understanding of how these structures work together to facilitate breathing.