Respiratory System Respiratory System n Main functions n

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Respiratory System

Respiratory System

Respiratory System n Main functions: n n Provide oxygen to cells Eliminate carbon dioxide

Respiratory System n Main functions: n n Provide oxygen to cells Eliminate carbon dioxide Works closely with cardiovascular system to accomplish gas exchange Gas exchange occurs in lungs

Upper Respiratory Passageways n n n Air enters through nose, past sinus cavities Air

Upper Respiratory Passageways n n n Air enters through nose, past sinus cavities Air then passes through pharynx Pharynx divided into three regions: n n n Nasopharynx (upper) Oropharynx (middle) Laryngeal (lower)

Lower Respiratory Passageways and Lungs n n Pharynx conducts air into trachea, through larynx

Lower Respiratory Passageways and Lungs n n 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 n n Smallest tubes = bronchioles Alveoli = microscopic air sacs where gas exchange occurs

Breathing n Ventilation made up of: n Inspiration n Phrenic nerve stimulates diaphragm to

Breathing n Ventilation made up of: n Inspiration n Phrenic nerve stimulates diaphragm to contract and flatten n Chest cavity enlarges n Change in pressure causes air to be pulled in n Expiration n Breathing muscles relax n Lungs return to original size n Air forced out

Pulmonary Ventilation

Pulmonary Ventilation

Gas Transport n Oxygen in blood n n n Attached to hemoglobin in red

Gas Transport n Oxygen in blood n n n Attached to hemoglobin in red blood cells Released to cells as needed Carbon dioxide mostly as carbonic acid n Amount formed regulates blood p. H

Clinical Aspects of Respiration n Pulmonary function affected by conditions that: n n n

Clinical Aspects of Respiration n Pulmonary function affected by conditions that: n n n Cause resistance to air flow Limit proper expansion of chest Conditions directly affecting respiratory system: n n n Infection Injury Allergy Aspiration Cancer

Changes in Ventilation n Changes in ventilation affect p. H of blood n n

Changes in Ventilation n Changes in ventilation affect p. H of blood n n Alkalosis = too much carbon dioxide exhaled by hyperventilation (blood too alkaline) Acidosis = too little carbon dioxide exhaled by hypoventilation (blood too acidic)

Infections n Pneumonia n n n Caused by several different microorganisms Leading cause of

Infections n Pneumonia n n n Caused by several different microorganisms Leading cause of death in debilitated patients Tuberculosis n n Caused by Mycobacterium tuberculosis Symptoms: n n n Fever Weight loss Weakness Cough Hemoptysis (sputum with blood) Influenza n Viral disease of respiratory tract

Emphysema n n Overexpansion and destruction of alveoli Causes: n n n Exposure to

Emphysema n n Overexpansion and destruction of alveoli Causes: n n n Exposure to cigarette smoke or pollution Chronic infection Classified under chronic obstructive pulmonary disease (COPD) heading

Asthma n n n Narrowing of bronchial tubes Main factor may be irritation caused

Asthma n n n Narrowing of bronchial tubes Main factor may be irritation caused by allergy Symptom of wheezing indicated by: n n Constriction of bronchial tubes Edema of bronchial linings Accumulation of mucus Extreme “attacks” may result in: n n Dyspnea Cyanosis

Disorders of Pleura n Pleurisy = inflammation of pleura, usually with infection n n

Disorders of Pleura n Pleurisy = inflammation of pleura, usually with infection n n Accumulation of substances between layers of pleura lead to other conditions: n n n Main symptom is pain which causes rapid, shallow breathing Pneumothorax Empyema Hemothorax Hydrothorax Fluids removed by thoracentesis

Lung Cancer n Leading cause of cancer-related deaths n n n Major risk factors:

Lung Cancer n Leading cause of cancer-related deaths n n n Major risk factors: n n n Usually cannot be detected early Metastasizes rapidly Cigarette smoking Other forms of cancer Diagnosed by: n n Radiographic studies CT scans Sputum examination Bronchoscope

Respiratory Distress Syndrome n n n Occurs in premature infants Results from lack of

Respiratory Distress Syndrome n n n Occurs in premature infants Results from lack of surfactant in lungs Acute respiratory distress syndrome n n May result from: n Trauma n Allergic reactions n Infection n Other causes Involves edema that can cause respiratory failure

Diagnosis n Methods for diagnosing respiratory disorders: n n n Radiographs CT scans MRI

Diagnosis n Methods for diagnosing respiratory disorders: n n n Radiographs CT scans MRI scans Lung scans Bronchoscopy Tests of pleural fluid removed with thoracentesis

Methods for diagnosing respiratory disorders n n n Examination of arterial blood gases Evaluating

Methods for diagnosing respiratory disorders n n n Examination of arterial blood gases Evaluating gas exchange, it measures: n Carbon dioxide n Oxygen n Bicarbonate n Blood p. H Pulse oximetry: Measure oxygen saturation of arterial blood Pulmonary function tests: Spirometer measures volume of air moved with varying degrees of effort