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Chapter 28 Respiratory Tract Infections, Neoplasms , and Childhood Disorders. Areas Involved in Respiratory Tract Infections. Upper respiratory tract Nose, oropharynx , and larynx Lower respiratory tract Lower airways and lungs. General symptoms of respiratory disease.

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Chapter 28 Respiratory Tract Infections, Neoplasms , and Childhood Disorders

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areas involved in respiratory tract infections
Areas Involved in Respiratory Tract Infections
  • Upper respiratory tract
    • Nose, oropharynx, and larynx
  • Lower respiratory tract
    • Lower airways and lungs
general symptoms of respiratory disease
General symptoms of respiratory disease
  • Hypoxia : Decreased levels of oxygen in the tissues
  • Hypoxemia : Decreased levels of oxygen in arterial blood
  • Hypercapnia : Increased levels of CO2 in the blood
  • Hypocapnia : Decreased levels of CO2 in the blood
  • Dyspnea : Difficulty breathing
  • Tachypnea : Rapid rate of breathing
  • Cyanosis : Bluish discoloration of skin and mucous membranes due to poor oxygenation of the blood
  • Hemoptysis : Blood in the sputum
common respiratory infections
Common Respiratory Infections
  • Common cold
  • Influenza
  • Pneumonia
  • Tuberculosis
  • Fungal infections of the lung

Upper respiratory tract Infections

The common cold

The most common viral pathogens for the “common cold” are rhinovirus, parainfluenza virus, respiratory syncytial virus, adenovirus and coronavirus.

  • These viruses tend to have seasonal variations in their peak incidence.
  • They gain entry to the body through the nasal mucosa and the surfaces of the eye. They are readily spread from person to person via respiratory secretions.
  • Manifestations of the common cold include:
      • Rhinitis: Inflammation of the nasal mucosa
      • Sinusitis :Inflammation of the sinus mucosa
      • Pharyngitis : Inflammation of the pharynx and throat
      • Headache
      • Nasal discharge and congestion
upper respiratory tract infections
Upper respiratory tract Infections


  • Influenza is a viral infection that can affect the upper or lower respiratory tract.
  • Three distinct forms of influenza virus have been identified: A, B and C, of these three variants, type A is the most common and causes the most serious illness.
  • The influenza virus is a highly transmissible respiratory pathogen.
  • Because the organism has a high tendency for genetic mutation, new variants of the virus are constantly arising in different places around the world. Serious pandemics (spread of infection across a large region) of influenza are seen every 8 to 10 years as a result of this genetic mutation .
upper respiratory tract infections1
Upper respiratory tract Infections


  • Symptoms of influenza infection:
      • Headache
      • Fever, chills
      • Muscle aches
      • Nasal discharge
      • Unproductive cough
      • Sore throat
  • Influenza infection can cause marked inflammation of the respiratory epithelium leading to acute tissue damage and a loss of ciliated cells that protect the respiratory passages from other organisms.
  • As a result, influenza infection may lead to co-infection of the respiratory passages with bacteria.
  • It is also possible for the influenza virus to infect the tissues of the lung itself to cause a viral pneumonia.

Upper respiratory tract Infections

Treatment of influenza:

Bed rest, fluids, warmth

Antiviral drugs

Influenza vaccine :

Provides protection against certain A and B influenza strains that are expected to be prevalent in a certain year.

The vaccine must be updated and administered yearly to be effective but will not be effective against influenza strains not included in the vaccine.

The influenza vaccine is particularly indicated in elderly people, in individuals weakened by other disease and in health-care workers



Upper respiratory tract Infections


Drugs for Treating Influenza:

  • Amantidine
    • Used orally or by aerosol administration
    • Effective only against type A influenza
    • Inhibits viral fusion, assembly and release from the infected host cell
  • Neuraminidase inhibitors (Zanamavir, Oseltamivir)
    • New drugs that can be used by inhalation (Zanamavir) or orally (Oseltamivir)
    • Effective against both type A and B influenza
    • Inhibits the activity of viral neuraminidase enzyme that is necessary for spread of the influenza virus
types of influenza vaccinations
Types of Influenza Vaccinations
  • Trivalent inactivated influenza vaccine (TIIV)
    • Developed in the 1940s
    • Administered by injection
  • Live, attenuated influenza vaccine (LAIV)
    • Approved for use in 2003
    • Administered intranasally
lower respiratory tract infections
Lower respiratory tract Infections


  • Pneumonia is a condition that involves inflammation of lower lung structures such as the alveoli or interstitial spaces.
  • It may be caused by bacteria or viruses such as pneumocystiscarinii.
  • The prevalence and severity of pneumonia have been heightened in recent years due to the emergence of HIV as well as antibiotic resistance.
  • Pneumonia may be classified according to the pathogen that is responsible for the infection.
  • There tend to be distinct organisms that cause pneumonia in the hospital setting vs. the community setting.
lower respiratory tract infections1
Lower respiratory tract Infections


  • • Community acquired pneumonia (CAP)
  • • Aspiration pneumonia
  • • Hospital
  • –Hospital acquired pneumonia (HAP)
  • –Ventilator associated pneumonia (VAP)
  • –Healthcare associated pneumonia (HCAP)
lower respiratory tract infections2
Lower respiratory tract Infections


Individuals Most at Risk for Pneumonia

  • Elderly
  • Those with viral infection
  • Chronically ill
  • AIDS or immunosuppressed patients
  • Smokers
  • Patients with chronic respiratory disease e.g. bronchial asthma.
potential pathogens
Potential Pathogens
  • Typical
  • Streptococcus pneumoniae
  • Hemophilusinfluenzae
  • Mycobacterium catarrhalis
  • Klebsiellapneumoniae
  • Atypical
  • Chlamydiapneumoniae
  • Legionellapneumophila
  • Mycoplasmapneumoniae.
factors facilitating development of pneumonia
Factors Facilitating Development of Pneumonia
  • Virulence of organism
  • Inoculum size
  • Impaired host defenses

Seen here are two lung abscesses,

    • one in the upper lobe and one in the lower lobe of this left lung.
  • An abscess is a complication of severe pneumonia, most typically from virulent organisms such as S. aureus.
  • Abscesses are complications of aspiration, where they appear more frequently in the right posterior lung.

The area of abscess is yellow tan, and it was very firm.

  • The infectious agent responsible here was Nocardia, which is known to produce chronic abscessing inflammation.
lower respiratory tract infections3
Lower respiratory tract Infections


A second classification scheme for pneumonia is based on the specific structures of the lung that the organisms infect and includes typical and atypical pneumonia.

Typical pneumonia

• Usually bacterial in origin.

• Organisms replicate in the spaces of the alveoli.


• Inflammation and fluid accumulation are seen in the alveoli.

• White cell infiltration and exudation can been seen on chest radiographs.

• High fever, chest pain, chills, and malaise are present.

• Purulent sputum is present.

• Some degree of hypoxemia is present.


Lower respiratory tract Infections


Atypical pneumonia

• Usually viral in origin.

• Organisms replicate in the spaces around the alveoli.


• Milder symptoms than typical pneumonia.

• Lack of white cell infiltration in alveoli.

• Lack of fluid accumulation in the alveoli.

• Not usually evident on radiographs.

• May make the patient susceptible to bacterial pneumonia.


Lower respiratory tract Infections


Treatment of pneumonia:

• Antibiotics if bacterial in origin. The health-care provider should consider the possibility that antibiotic-resistant organisms are present.

• Oxygen therapy for hypoxemia.

• A vaccine for pneumococcal pneumonia is currently available and highly effective. This vaccine should be considered in high-risk individuals.

  • Caused by a mycobacterium, M. tuberculosis
    • Outer waxy capsule makes the organism more resistant to destruction
  • Infects practically any organ of the body; the lungs are most frequently involved
  • Macrophage-directed attack, resulting parenchymal destruction
  • Cell-mediated immune response
    • Confers resistance to the organism
    • Development of tissue hypersensitivity
forms of tuberculosis
Forms of Tuberculosis
  • M. tuberculosis hominis (human tuberculosis)
    • Airborne infection spread by minute droplet nuclei harbored in the respiratory secretions of persons with active tuberculosis
    • Living under crowded and confined conditions increases the risk for spread of the disease.
  • Bovine tuberculosis
    • Acquired by drinking milk from infected cows; initially affects the gastrointestinal tract
    • Has been virtually eradicated in North America and other developed countries
positive tuberculin skin test
Positive Tuberculin Skin Test
  • Results from a cell-mediated immune response
    • Implies that a person has been infected with M. tuberculosis and has mounted a cell-mediated immune response
    • Does not mean the person has active tuberculosis
  • Which of the following involves infection of the entire respiratory tract?
  • Common cold
  • Pneumonia
  • Tuberculosis
  • Cancer


  • Common cold
  • Pneumonia: Pneumonia can involve all respiratory tissues and, due to its virulence, is a major health risk.
  • Tuberculosis
  • Cancer
classification and spread of fungi
Classification and Spread of Fungi
  • Yeasts
    • Are round and grow by budding
  • Molds
    • Form tubular structures called hyphae
    • Grow by branching and forming spores
  • Dimorphic fungi
    • Grow as yeasts at body temperatures and as molds at room temperatures
  • Mechanisms of fungal spread
    • Inhalation of spores
laboratory tests to diagnose histoplasmosis
Laboratory Tests to Diagnose Histoplasmosis
  • Cultures
  • Fungal stain
  • Antigen detection
  • Serologic tests for antibodies

The dense white encircling tumor mass is arising from the visceral pleura and is a mesothelioma.

respiratory disorders in the neonate
Respiratory Disorders in the Neonate
  • Respiratory distress syndrome
  • Bronchopulmonary dysplasia
respiratory disorders in children
Respiratory Disorders in Children
  • Upper airway infections
    • Viral croup
    • Spasmodic croup
    • Epiglottis
  • Lower airway infections
    • Acute bronchiolitis
impending respiratory failure in infants and children
Impending Respiratory Failure in Infants and Children
  • Rapid breathing
  • Exaggerated use of the accessory muscles
  • Retractions
  • Nasal flaring
  • Grunting during expiration
  • The lungs are a common site of secondary tumor development. Why?
  • Due to the highly vascular nature and small capillaries
  • Due to the fragility of the cells
  • Due to the rapid replication of type I alveolar cells
  • Due to dumb luck


  • Due to the highly vascular nature and small capillaries
  • Due to the fragility of the cells
  • Due to the rapid replication of type I alveolar cells
  • Due to dumb luck
gases of respiration
Gases of Respiration
  • Primary function of respiratory system
    • Remove CO2
    • Add of O2
  • Insufficient exchange of gases
    • Hypoxemia
    • Hypercapnia
  • Hypoxemia results from
    • Inadequate O2 in the air
    • Diseases of the respiratory system
    • Dysfunction of the neurological system
    • Alterations in circulatory function
  • Mechanisms
    • Hypoventilation
    • Impaired diffusion of gases
    • Inadequate circulation of blood through the pulmonary capillaries
    • Mismatching of ventilation and perfusion
manifestations of hypoxemia
Manifestations of Hypoxemia
  • Mild hypoxemia
    • Metabolic acidosis
    • Increase in heart rate
    • Peripheral vasoconstriction
    • Diaphoresis
    • Increase in blood pressure
    • Slight impairment of mental performance
manifestations of hypoxemia cont
Manifestations of Hypoxemia (cont.)
  • Chronic hypoxemia
    • Manifestations of chronic hypoxia may be insidious in onset and attributed to other causes
      • Compensation masks condition
    • Increased ventilation
    • Pulmonary vasoconstriction
    • Increased production of red blood cells
    • Cyanosis
  • Increased arterial PCO2
  • Caused by hypoventilation or mismatching of ventilation and perfusion
  • Effects
    • Acid-base balance (decreased pH, respiratory acidosis)
    • Kidney function
    • Nervous system function
    • Cardiovascular function
causes of disorders of lung inflation
Causes of Disorders of Lung Inflation
  • Conditions that produce lung compression or lung collapse
    • Compression of the lung by an accumulation of fluid in the intrapleural space
    • Complete collapse of an entire lung as in pneumothorax
    • Collapse of a segment of the lung as in atelectasis
characteristics and symptoms of pleural pain
Characteristics and Symptoms of Pleural Pain
  • Abrupt in onset
  • Unilateral, localized to lower and lateral part of the chest
  • May be referred to the shoulder
  • Usually made worse by chest movements
  • Tidal volumes are kept small.
  • Breathing becomes more rapid.
  • Reflex splinting of the chest may occur.
pleural effusion
Pleural Effusion
  • Definition
    • An abnormal collection of fluid in the pleural cavity
  • Types of fluid
    • Transudate
    • Exudate
    • Purulent drainage (empyema)
    • Chyle
    • Blood
diagnosis and treatment of pleural effusion
Diagnosis and Treatment of Pleural Effusion
  • Diagnosis
    • Chest radiographs, chest ultrasound
    • Computed tomography (CT)
  • Treatment: directed at the cause of the disorder
    • Thoracentesis
    • Injection of a sclerosing agent into the pleural cavity
    • Open surgical drainage
disorders of the pleura
Disorders of the Pleura
  • Pleural effusion: abnormal collection of fluid in the pleural cavity
    • Transudate or exudate, purulent (containing pus), chyle, or sanguineous (bloody)
  • Hemothorax
  • Pleuritis
  • Chylothorax
  • Atelectasis
  • Empyema
types of pneumothorax
Types of Pneumothorax
  • Spontaneous pneumothorax
    • Occurs when an air-filled blister on the lung surface ruptures
  • Traumatic pneumothorax
    • Caused by penetrating or nonpenetrating injuries
  • Tension pneumothorax
    • Occurs when the intrapleural pressure exceeds atmospheric pressure
  • Definition
    • Incomplete expansion of a lung or portion of a lung
  • Causes
    • Airway obstruction
    • Lung compression such as occurs in pneumothorax or pleural effusion
    • Increased recoil of the lung due to loss of pulmonary surfactant
types of atelectasis
Types of Atelectasis
  • Primary
    • Present at birth
  • Secondary
    • Develops in the neonatal period or later in life
  • Which of the following is a disorder caused by abnormal accumulation of fluid in the pleural space?
  • Pneumothorax
  • Pleural effusion
  • Atelectasis
  • Hypercapnia
  • Pneumothorax
  • Pleural diffusion: Pleural diffusion can be caused by transudate, exudate, chyle, or other fluid.
  • Atelectasis
  • Hypercapnia
physiology of airway disease
Upper respiratory tract

Trachea and major bronchi

Lower respiratory tract

Bronchi and alveoli

Creation of negative pressure

Effects of CO2/pH

Role of inflammatory mediators

Increase airway responsiveness by

Producing bronchospasm

Increasing mucus secretion

Producing injury to the mucosal lining of the airways

Physiology of Airway Disease
functions of bronchial smooth muscle
Functions of Bronchial Smooth Muscle
  • The tone of the bronchial smooth muscles surrounding the airways determines airway radius.
  • The presence or absence of airway secretions influence airway patency.
  • Bronchial smooth muscle is innervated by the autonomic nervous system.
    • Parasympathetic: vagal control
      • Bronchoconstrictor
    • Sympathetic: 2-adrenergic receptors
      • Bronchodilator
factors involved in the pathophysiology of asthma
Factors Involved in the Pathophysiology of Asthma
  • Genetic
    • Atopy
      • Early vs. late phase
  • Environmental
    • Viruses
    • Allergens
    • Occupational exposure
factors contributing to the development of an asthmatic attack
Factors Contributing to the Development of an Asthmatic Attack
  • Allergens
  • Respiratory tract infections
  • Exercise
  • Drugs and chemicals
  • Hormonal changes and emotional upsets
  • Airborne pollutants
  • Gastroesophageal reflux
classifications of asthma severity
Classifications of Asthma Severity
  • Mild intermittent
  • Mild persistent
  • Moderate persistent
  • Severe persistent
  • Which of the following have not been implicated in the development of asthma?
  • Allergens
  • Respiratory tract infections
  • Diet
  • Drugs and chemicals
  • Hormonal changes and emotional upsets
  • Airborne pollutants
  • Gastroesophageal reflux
  • Allergens
  • Respiratory tract infections
  • Diet: Diet does not affect the respiratory tract other than via allergic reactions.
  • Drugs and chemicals
  • Hormonal changes and emotional upsets
  • Airborne pollutants
  • Gastroesophageal reflux
chronic obstructive airway disease
Chronic Obstructive Airway Disease
  • Inflammation and fibrosis of the bronchial wall
  • Hypertrophy of the submucosal glands
  • Hypersecretion of mucus
  • Loss of elastic lung fibers
    • Impairs the expiratory flow rate, increases air trapping, and predisposes to airway collapse
  • Alveolar tissue
    • Decreases the surface area for gas exchange
causes of chronic obstructive airway disease
Causes of Chronic Obstructive Airway Disease
  • Chronic bronchitis
  • Emphysema
  • Bronchiectasis
  • Cystic fibrosis

Bronchiectasisoccurs when there is obstruction or infection with inflammation and destruction of bronchi so that there is permanent

pulmonary fibrosis
Pulmonary Fibrosis
  • The alveolitis that produces fibroblast proliferation and collagen deposition is progressive over time.
  • Sarcoidosis
characteristics of type a pulmonary emphysema
Characteristics of Type A Pulmonary Emphysema
  • Smoking history
  • Age of onset: 40–50 years
  • Often dramatic barrel chest
  • Weight loss
  • Decreased breath sounds
  • Normal blood gases until late in disease process
  • Corpulmonale only in advanced cases
  • Slowly debilitating disease

There are two major types of emphysema: centrilobular (centriacinar) and panlobular (panacinar).


Centrilobular emphysema

    • "dirty holes”
  • This pattern is typical for smokers.
characteristics of type b chronic bronchitis
Characteristics of Type B Chronic Bronchitis
  • Smoking history
  • Age of onset 30–40 years
  • Barrel chest may be present
  • Shortness of breath predominant early symptom
  • Rhonchi often present
  • Sputum frequent early manifestation
characteristics of type b chronic bronchitis cont
Characteristics of Type B Chronic Bronchitis (cont.)
  • Often dramatic cyanosis
  • Hypercapnia and hypoxemia may be present
  • Frequent cor pulmonale and polycythemia
  • Numerous life-threatening episodes due to acute exacerbations
types of chronic obstructive pulmonary disease
Types of Chronic Obstructive Pulmonary Disease
  • Emphysema
    • Enlargement of air spaces and destruction of lung tissue
    • Types: centriacinarand panacinar
  • Chronic obstructive bronchitis
    • Obstruction of small airways
  • Permanent dilation of the bronchi and bronchioles
  • Secondary to persisting infection or obstruction
  • Manifestations
    • Atelectasis
    • Obstruction of the smaller airways
    • Diffuse bronchitis
    • Recurrent bronchopulmonary infection
    • Coughing; production of copious amounts of foul-smelling, purulent sputum; hemoptysis
    • Weight loss and anemia are common.
cystic fibrosis
Cystic Fibrosis
  • Definition
    • An autosomal-recessive disorder involving fluid secretion in the exocrine glands and the epithelial lining of the respiratory, gastrointestinal, and reproductive tracts
  • Cause
    • Mutations in a single gene on the long arm of chromosome 7 that encodes for the cystic fibrosis transmembrane regulator (CFTR), which functions as a chloride (Cl-) channel in epithelial cells
manifestations of cystic fibrosis
Manifestations of Cystic Fibrosis
  • Pancreatic exocrine deficiency
  • Pancreatitis
  • Elevation of sodium chloride in the sweat
  • Excessive loss of sodium in the sweat
  • Nasal polyps
  • Sinus infections
  • Cholelithiasis
diffuse interstitial lung diseases
Diffuse Interstitial Lung Diseases
  • Definition
    • A diverse group of lung disorders that produce similar inflammatory and fibrotic changes in the interstitium or interalveolar septa of the lung
  • Types
    • Sarcoidosis
    • Occupational lung diseases
    • Hypersensitivity pneumonitis
    • Lung diseases caused by exposure to toxic drugs
occupational lung diseases
Occupational Lung Diseases
  • Pneumoconioses
    • Caused by inhalation of inorganic dusts and particulate matter
  • Hypersensitivity diseases
    • Caused by inhalation of organic dusts and related occupational antigens
  • Byssinosis: occurs in cotton workers; has characteristics of the pneumoconioses and hypersensitivity lung disease
pulmonary embolism
Pulmonary Embolism
  • Development
    • A blood-borne substance lodges in a branch of the pulmonary artery and obstructs the flow
  • Types
    • Thrombus: arising from deep vein thrombosis
    • Fat: mobilized from the bone marrow after a fracture or from a traumatized fat depot
    • Amniotic fluid: enters the maternal circulation after rupture of the membranes at the time of delivery
pulmonary hypertension
Signs and symptoms of secondary pulmonary hypertension

Dyspnea and fatigue

Peripheral edema


Signs of right heart failure (corpulmonale)

A disorder characterized by an elevation of pressure within the pulmonary circulation

Pulmonary arterial hypertension

Pulmonary Hypertension
cor pulmonale
  • Right heart failure resulting from primary lung disease and long-standing primary or secondary pulmonary hypertension
  • Involves hypertrophy and the eventual failure of the right ventricle
  • Manifestations include the signs and symptoms of primary lung disease and the signs of right-sided heart failure.
causes of acute respiratory distress syndrome
Causes of Acute Respiratory Distress Syndrome
  • Aspiration of gastric contents
  • Major trauma (with or without fat emboli)
  • Sepsis secondary to pulmonary or nonpulmonary infections
  • Acute pancreatitis
  • Hematologic disorders
  • Metabolic events
  • Reactions to drugs and toxins
causes of respiratory failure
Causes of Respiratory Failure
  • Impaired ventilation
    • Upper airway obstruction
    • Weakness of paralysis of respiratory muscles
    • Chest wall injury
  • Impaired matching of ventilation and perfusion
  • Impaired diffusion
    • Pulmonary edema
    • Respiratory distress syndrome
treatment of respiratory failure
Treatment of Respiratory Failure
  • Respiratory supportive care directed toward maintenance of adequate gas exchange
  • Establishment of an airway
  • Use of bronchodilating drugs
  • Antibiotics for respiratory infections
  • Ensure adequate oxygenation
  • Which of the following has been implicated as a causative factor in right ventricular failure?
  • Corpulmonale
  • Pneumothorax
  • Cystic fibrosis
  • Acute respiratory distress syndrome


  • Corpulmonale: Corpulmonale will result in right ventricle failure due to the increase in workload.
  • Pneumothorax
  • Cystic fibrosis
  • Acute respiratory distress syndrome
  • The most common port of entry for cold viruses is _______.
  • Inhalation
  • Small cuts
  • Food
  • Conjunctival surface of the eyes
  • Fingers

The most common port of entry for cold viruses is _______.

  • Inhalation
  • Small cuts
  • Food
  • Conjunctival surface of the eyes
  • Fingers


factors affecting the signs and symptoms of respiratory tract infections
Factors Affecting the Signs and Symptoms of Respiratory Tract Infections
  • The function of the structure involved
  • The severity of the infectious process
  • The person’s age and general health status
rhinitis and sinusitis
Rhinitis and Sinusitis
  • Rhinitis
    • Inflammation of the nasal mucosa
  • Sinusitis
    • Inflammation of the paranasal sinuses
types of sinuses
Types of Sinuses
  • Paranasal sinuses
    • Air cells connected by narrow openings or ostia with the superior, middle, and inferior nasal turbinates of the nasal cavity
  • Maxillary sinus
    • Inferior to the bony orbit and superior to the hard palate
    • Its opening is located superiorly and medially in the sinus, a location that impedes drainage.
  • Frontal sinuses
    • Open into the middle meatus of the nasal cavity
transmission of common cold
Transmission of Common Cold
  • Viral infection of the upper respiratory tract
    • Rhinoviruses, parainfluenza viruses, respiratory syncytial virus, coronaviruses, and adenoviruses
  • Fingers are the greatest source of spread
  • Coughing, sneezing
    • The nasal mucosa and conjunctival surface of the eyes are the most common portals of entry for the virus.
types of sinuses cont
Types of Sinuses (cont.)
  • Sphenoid sinus
    • Just anterior to the pituitary fossa behind the posterior ethmoid sinuses
    • Its paired openings drain into the sphenoethmoidal recess at the top of the nasal cavity.
  • Ethmoid sinuses
    • Comprise 3–15 air cells on each side, with each maintaining a separate path to the nasal chamber
allergic rhinosinusitis
Allergic Rhinosinusitis
  • Occurrence
    • Occurs in conjunction with allergic rhinitis
    • Mucosal changes are the same as allergic rhinitis
  • Symptoms
    • Nasal stuffiness, itching and burning of the nose, frequent bouts of sneezing, recurrent frontal headache, watery nasal discharge
  • Treatment
    • Oral antihistamines, nasal decongestants, and intranasal cromolyn


  • Inhalation
  • Small cuts
  • Food
  • Conjunctival surface of the eyes: The eyes and the nasal mucosa are the most common ports of entry.
  • Fingers
types of influenza viruses
Types of Influenza Viruses
  • Type A
    • Most common type
    • Can infect multiple species
    • Causes the most severe disease
    • Further divided into subtypes based on two surface antigens: hemagglutinin (H) and neuraminidase (N)
  • Type B
    • Has not been categorized into subtypes
lung cancer
Causative factors



Familial predisposition

Primary lung tumors (95%) vs. bronchial, glandular, lymphoma

Secondary via metastasis

Lung Cancer
categories of bronchogenic carcinomas
Categories of Bronchogenic Carcinomas
  • Squamous cell lung carcinoma (25–40%)
    • Closely related to smoking
  • Adenocarcinoma (20–40%)
    • Most common in North America
  • Small cell carcinoma (20–25%)
    • Small round to oval cells, highly malignant
  • Large cell carcinoma (10–15%)
    • Large polygonal cells, spread early in development

This is another sqamous cell carcinoma that extends from hilum to pleura.

  • The black areas represent anthracotic pigment trapped in the tumor.
categories of the manifestation of lung cancer
Categories of the Manifestation of Lung Cancer
  • Those due to involvement of the lung and adjacent structures
  • The effects of local spread and metastasis
  • The nonmetastaticparaneoplastic manifestations involving endocrine, neurologic, and connective tissue function
  • Nonspecific symptoms such as anorexia and weight loss
classifications of rhinosinusitis
Classifications of Rhinosinusitis
  • Acute rhinosinusitis
    • May be of viral, bacterial, or mixed viral-bacterial origin
    • May last from 5 to 7 days up to 4 weeks
  • Subacute rhinosinusitis
    • Lasts from 4 weeks to less than 12 weeks
  • Chronic rhinosinusitis
    • Lasts beyond 12 weeks
function of the respiratory system
Function of the Respiratory System
  • Gas exchange
    • Oxygen from air to lungs
    • Carbon dioxide from blood to atmosphere
  • Host defense
    • Barrier to outside environment
  • Metabolic organ
    • Synthesizes and metabolizes different components
structural organization of the respiratory system
Structural Organization of the Respiratory System
  • Consists of the air passages and the lungs
  • Divided into two parts by function:
    • Conducting airways, through which air moves as it passes between the atmosphere and the lungs
    • Respiratory tissues of the lungs, where gas exchange takes place
structures of the airways

Nasal passages

Mouth and pharynx





Mucociliary blanket

Respiratory tissues

Alveolar bundle

Respiratory membrane

Structures of the Airways
  • Depends on the conducting airways
    • Nasopharynx and oropharynx
    • Larynx
    • Tracheobronchial tree
  • Function
    • Moves air out of the lungs but does not participate in gas exchange
structure and function of the larynx
Structure and Function of the Larynx
  • Structure
    • Connects the oropharynx with the trachea
    • Located in a strategic position between the upper airways and the lungs
  • Functions
    • Helps produce speech
    • Protects the lungs from substances other than air
structures of the lungs
Structures of the Lungs
  • Soft, spongy, cone-shaped organs located side by side in the chest cavity
    • Separated from each other by the mediastinum and its contents
    • Divided into lobes (3 in the right lung, 2 in the left)
  • Apex: upper part of the lung; lies against the top of the thoracic cavity
  • Base: lower part of the lung; lies against the diaphragm
composition of the alveolar structures
Composition of the Alveolar Structures
  • Type I alveolar cells
    • Flat, squamous epithelial cells across which gas exchange takes place
  • Type II alveolar cells
    • Produce surfactant, a lipoprotein substance that decreases the surface tension in the alveoli and allows for greater ease of lung inflation
lung circulation
Lung Circulation
  • Pulmonary circulation
    • Arises from the pulmonary artery
    • Provides for the gas exchange function of the lungs
  • Bronchial circulation
    • Arises from the thoracic aorta
    • Supplies the lungs and other lung structures with oxygen
    • Distributes blood to the conducting airways
    • Warms and humidifies incoming air
ventilation and gas exchange
Ventilation and Gas Exchange
  • Ventilation
    • The movement of gases into and out of the lungs
  • Inspiration
    • Air is drawn into the lungs as the respiratory muscles expand the chest cavity.
  • Expiration
    • Air moves out of the lungs as the chest muscles recoil and the chest cavity becomes smaller.
  • Which of the following is directly responsible for gas exchange?
    • Trachea
    • Bronchi
    • Bronchial circulation
    • Pulmonary circulation
    • Respiratory membrane
  • Trachea
  • Bronchi
  • Bronchial circulation
  • Pulmonary circulation
  • Respiratory membrane: The respiratory membrane is the anatomical site of gas exchange in the lungs. It is located in the alveoli.
properties of gases
Properties of Gases
  • Respiratory pressures
  • Atmospheric pressure
    • Partial pressures
  • Humidity
    • Temperature effects
respiratory pressures
Respiratory Pressures
  • Intrapulmonary pressure or alveolar pressure
    • Pressure inside the airways and alveoli of the lungs
  • Intrapleural pressure
    • Pressure in the pleural cavity
  • Intrathoracic pressure
    • Pressure in the thoracic cavity
lung compliance
Lung Compliance
  • Lung compliance
    • C = ΔV/ΔP
    • The change in lung volume (ΔV) that can be accomplished with a given change in respiratory pressure (ΔP)
airway resistance
Airway Resistance
  • The volume of air that moves into and out of the air-exchange portion of the lungs
  • Directly related to the pressure difference between the lungs and the atmosphere
  • Inversely related to the resistance the air encounters as it moves through the airways
lung volumes
Lung Volumes
  • Tidal volume (TV)
    • Amount of air that moves into and out of the lungs during a normal breath
  • Inspiratory reserve volume (IRV)
    • The maximum amount of air that can be inspired in excess of the normal TV
lung volumes cont
Lung Volumes (cont.)
  • Expiratory reserve volume (ERV)
    • Maximum amount of air that can be exhaled in excess of the normal TV
  • Residual volume
    • The air that remains in the lungs after forced respiration
lung capacities
Lung Capacities
  • Vital capacity: equals the IRV plus the TV plus the ERV
    • The amount of air that can be exhaled from the point of maximal inspiration
  • Inspiratory capacity: equals the TV plus the IRV
    • The amount of air a person can breathe beginning at the normal expiratory level and distending the lungs to the maximal amount
lung capacities cont
Lung Capacities (cont.)
  • Functional residual capacity: the sum of the RV and ERV
    • The volume of air that remains in the lungs at the end of normal expiration
  • Total lung capacity: the sum of all the volumes in the lungs
pulmonary function studies
Pulmonary Function Studies
  • Maximum voluntary ventilation
    • The volume of air a person can move into and out of the lungs during maximum effort lasting for 12–15 seconds
  • Forced expiratory vital capacity (FVC)
    • Involves full inspiration to total lung capacity followed by forceful maximal expiration
pulmonary function studies cont
Pulmonary Function Studies (cont.)
  • Forced expiratory volume (FEV)
    • The expiratory volume achieved in a given time period
  • Forced inspiratory vital flow (FIF)
    • The respiratory response during rapid maximal inspiration
  • Which of the following make up the vital capacity?
  • IRV +ERV
  • Vt + ERV
  • Vt + IRV + ERV
  • Vt + IRV – Residual volume


  • IRV +ERV
  • Vt + ERV
  • Vt + IRV + ERV: These are the basic components of the vital capacity.
  • Vt + IRV – Residual volume
processes of pulmonary gas exchange
Processes of Pulmonary Gas Exchange
  • Ventilation
    • The flow of gases into and out of the alveoli of the lungs
  • Perfusion
    • The flow of blood in the adjacent pulmonary capillaries
  • Diffusion
    • Transfer of gases between the alveoli and the pulmonary capillaries
types of air movement in the lung
Types of Air Movement in the Lung
  • Bulk flow
    • Occurs in the conducting airways
    • Controlled by pressure differences between the mouth and that of airways in the lung
  • Diffusion
    • The movement of gases in the alveoli and across the alveolar capillary membrane
types of dead space
Types of Dead Space
  • Anatomic dead space
    • That contained in the conducting airways
  • Alveolar dead space
    • That contained in the respiratory portion of the lung
  • Physiologic dead space
    • The anatomic dead space plus the alveolar dead space
types of shunts
Types of Shunts
  • Anatomic shunt
    • Blood moves from the venous to the arterial side of the circulation without moving through the lungs
  • Physiologic shunt
    • Mismatching of ventilation and perfusion with the lung
    • Results in insufficient ventilation to provide the oxygen needed to oxygenate the blood flowing through the alveolar capillaries
matching ventilation and perfusion
Matching Ventilation and Perfusion
  • Required for exchange of gases between the air in the alveoli and the blood in pulmonary capillaries
  • Two factors interfere with the process:
    • Dead air space and shunt
  • The blood oxygen level reflects the mixing of blood from alveolar dead space and physiologic shunting areas as it moves into the pulmonary veins.
factors affecting alveolar capillary gas exchange
Factors Affecting Alveolar–Capillary Gas Exchange
  • Surface area available for diffusion
  • Thickness of the alveolar-capacity membrane
  • Partial pressure of alveolar gases
  • Solubility and molecular weight of the gas
oxygen and carbon dioxide transport
Oxygen and Carbon Dioxide Transport
  • PO2 of arterial blood normally is above 80 mm Hg.
    • In chemical combination with hemoglobin
      • 98–99%
      • Oxyhemoglobin
      • Binding affinity of hemoglobin for oxygen
    • In the dissolved state
oxygen and carbon dioxide transport cont
Oxygen and Carbon Dioxide Transport (cont.)
  • The PCO2 is in the range of 35–45 mm Hg.
    • Dissolved in carbon dioxide (10%)
    • Attached to hemoglobin (30%)
    • Bicarbonate (60%)
      • Acid-base balance is influenced by the amount of dissolved carbon dioxide and the bicarbonate level in the blood
control of breathing
Control of Breathing
  • Respiratory center
    • Pacemaker center
      • Pneumotaxic center
      • Apneustic center
    • Phrenic nerve
control of breathing cont
Control of Breathing (cont.)
  • Automatic regulation of ventilation
    • Controlled by input from two types of sensors or receptors
      • Chemoreceptors: monitor blood levels of oxygen and carbon dioxide and adjust ventilation to meet the changing metabolic needs of the body
      • Lung receptors: monitor breathing patterns and lung function
control of breathing cont1
Control of Breathing (cont.)
  • Voluntary regulation of ventilation
    • Integrates breathing with voluntary acts such as speaking, blowing, and singing
    • These acts, initiated by the motor and premotor cortex, cause a temporary suspension of automatic breathing.
cough reflex
Cough Reflex
  • Neurally mediated reflex that protects the lungs
    • Accumulation of secretions
    • Entry of irritating and destructive substances
cheyne stokes
  • Abnormal pattern of breathing
    • Characterized by oscillation of ventilation between apnea and hyperpnea
    • Compensate for changing serum partial pressures
mechanisms involved in dyspnea
Stimulation of lung receptors

Increased sensitivity to changes in ventilation perceived through central nervous system mechanisms

Reduced ventilatory capacity or breathing reserve

Stimulation of neural receptors in the muscle fibers of the intercostals and diaphragm and of receptors in the skeletal joints

Associated conditions

Primary lung diseases

Heart disease

Neuromuscular disorders

Mechanisms Involved in Dyspnea
  • Which of the following accurately describes your breathing pattern after running to class?
  • Cheyne-Stokes
  • Normal
  • Dyspnea
  • Eupnea
  • Hypoxemia
  • Cheyne-Stokes
  • Normal
  • Dyspnea: Dyspnea is simply labored breathing; it is not necessarily pathological in nature.
  • Eupnea
  • Hypoxemia
stages of lung development
Stages of Lung Development
  • Embryonic period
  • Pseudoglandular period
  • Canicular period
  • Saccular period
  • Alveolar period