Download Respiratory

Respiratory System
Respiratory System
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Main functions:
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Provide oxygen to cells
Eliminate carbon dioxide
Works closely with cardiovascular
system to accomplish gas exchange
Gas exchange occurs in lungs
Upper Respiratory
Passageways
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Air enters through nose, past sinus
cavities
Air then passes through pharynx
Pharynx divided into three regions:
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Nasopharynx (upper)
Oropharynx (middle)
Laryngeal (lower)
Lower Respiratory Passageways
and Lungs
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Pharynx conducts air into trachea, through
larynx and glottis
Epiglottis prevents food from entering respiratory
tract
Larynx contains vocal cords (allows speech)
Trachea divides into bronchus
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Smallest tubes = bronchioles
Alveoli = microscopic air sacs where gas exchange
occurs
Breathing
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Ventilation made up of:
 Inspiration
 Phrenic nerve stimulates diaphragm to
contract and flatten
 Chest cavity enlarges
 Change in pressure causes air to be pulled
in
 Expiration
 Breathing muscles relax
 Lungs return to original size
 Air forced out
Pulmonary Ventilation
Gas Transport
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Oxygen in blood
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Attached to hemoglobin in red blood
cells
Released to cells as needed
Carbon dioxide mostly as carbonic
acid
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Amount formed regulates blood pH
Clinical Aspects of
Respiration
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Pulmonary function affected by conditions that:
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Cause resistance to air flow
Limit proper expansion of chest
Conditions directly affecting respiratory system:
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Infection
Injury
Allergy
Aspiration
Cancer
Changes in Ventilation
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Changes in ventilation affect pH of blood
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Alkalosis = too much carbon dioxide exhaled
by hyperventilation (blood too alkaline)
Acidosis = too little carbon dioxide exhaled by
hypoventilation (blood too acidic)
Infections
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Pneumonia
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Caused by several different microorganisms
Leading cause of death in debilitated patients
Tuberculosis
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Caused by Mycobacterium tuberculosis
Symptoms:
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Fever
Weight loss
Weakness
Cough
Hemoptysis (sputum with blood)
Influenza
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Viral disease of respiratory tract
Emphysema
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Overexpansion and destruction of
alveoli
Causes:
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Exposure to cigarette smoke or
pollution
Chronic infection
Classified under chronic obstructive
pulmonary disease (COPD) heading
Asthma
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Narrowing of bronchial tubes
Main factor may be irritation caused by
allergy
Symptom of wheezing indicated by:
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Constriction of bronchial tubes
Edema of bronchial linings
Accumulation of mucus
Extreme “attacks” may result in:
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Dyspnea
Cyanosis
Disorders of Pleura
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Pleurisy = inflammation of pleura, usually with
infection
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Accumulation of substances between layers of
pleura lead to other conditions:
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Main symptom is pain which causes rapid, shallow
breathing
Pneumothorax
Empyema
Hemothorax
Hydrothorax
Fluids removed by thoracentesis
Lung Cancer
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Leading cause of cancer-related deaths
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Major risk factors:
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Usually cannot be detected early
Metastasizes rapidly
Cigarette smoking
Other forms of cancer
Diagnosed by:
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Radiographic studies
CT scans
Sputum examination
Bronchoscope
Respiratory Distress
Syndrome
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Occurs in premature infants
Results from lack of surfactant in lungs
Acute respiratory distress syndrome
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May result from:
 Trauma
 Allergic reactions
 Infection
 Other causes
Involves edema that can cause respiratory
failure
Diagnosis
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Methods for diagnosing respiratory
disorders:
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Radiographs
CT scans
MRI scans
Lung scans
Bronchoscopy
Tests of pleural fluid removed with
thoracentesis
Methods for diagnosing
respiratory disorders
 Examination of arterial blood gases
Evaluating gas exchange, it measures:
Carbon dioxide
Oxygen
Bicarbonate
Blood pH
 Pulse oximetry: Measure oxygen saturation of
arterial blood
 Pulmonary function tests: Spirometer
measures volume of air moved with varying
degrees of effort