Respiratory system

Applied Anatomy &Physiology

Anatomy

The respiratory system consists of

1)The Upper airway :

Nose, mouth and larynx

2)The Lower airways

Trachea and the two lungs.

Within the lungs, the bronchi transport air with

oxygen to the alveoli on inspiration and carry

waste gases (e.g. carbon dioxide) away on

expiration.

The acinus is the gas exchange unit of the lung and

consists of branching respiratory bronchioles

leading to clusters of alveoli.

Alveoli are tiny air sacs lined by flattened epithelial

cells and covered in capillaries where gas

exchanges occur

The alveoli and capillaries have extremely

thin walls and come into very close contact

(the alveolar capillary membrane), so gases

can rapidly diffuse between them. There are

approximately 300 million alveoli in each

lung for gas exchange with a total surface

area of 40-80 meter square.

.The lungs has two blood supplies:

1)The bronchial arteries: which arise from theaorta and supply oxygenated blood to thebronchial walls.

2)The pulmonary arteries: which deliverdeoxygenated blood to the capillariessurrounding the alveoli.

Applied Anatomy &Physiology

History

1)Presenting symptoms

2)Past history

3)Drug history

4)Family history

5)Social history

*Respiratory symptoms:1)Cough

2)Wheezing

3)Stridor

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

Cough

Cough is a characteristic sound caused by a forced expulsion against an initially closed glottis.

Acute cough is one lasting less than 3 weeks; chronic cough lasts more than 8 weeks.

The most common cause of acute cough is acute upper respiratory tract viral infection. Acute cough is usually self-limiting and benign, but may occur in more serious conditions

Timing of cough

• 1)nocturnal cough disturbing sleep is a feature of asthma .

• 2)chronic cough which improves during weekends and holidays is a feature of occupational asthma.

• 3)cough during or after swallowing liquids is a feature of neuromuscular diseases

• 4)cough on lying down in evening may be due to GERD

• 5)early morning cough is feature of rhino-sinusitis or post nasal drip .

.Cough features:1)Prolonged wheezy cough: asthma and COPD.2) Paroxysmal dry cough after a viral infection that lasts several months (bronchial hyperreactivity),when chronic dry cough suggest ILD(pulm. fibrosis).3)A feeble non-explosive ‘bovine’ cough: with hoarseness suggests lung cancer invading the left recurrent laryngeal nerve causing left vocal cord paralysis, but may also occur with respiratory muscle weakness due to neuromuscular disorders.4)Harsh, painful cough with hoarseness: laryngeal inflammation.5)A moist cough suggests secretions in the upper and larger airways from bronchial infection and bronchiectasis and when persistent moist ‘smoker’s cough’ in the morning is typical of chronic bronchitis.

*Respiratory symptoms:

1)Cough

2)Wheezing

3)Stridors

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

WheezingWheeze is a high-pitched whistling sound

produced by air passing through narrowed

small airways.

It occurs with expiration.

Timing:

1)Nocturnal wheezing: bronch.asthma

&PNDS

2)In the morning : COPD.

*Respiratory symptoms:1)Cough

2)Wheezing

3)Stridors

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

Stridors

Stridor is a high-pitched, often harsh noise produced by airflow turbulence through a partial obstruction of the airway.

It occurs most commonly on inspiration but also on expiration or biphasically.

Timing with respiration:

1) Inspiratory stridor: indicates narrowing at the vocal cords.

2)Biphasic stridor suggests tracheal obstruction.

3)Stridor on expiration : suggests tracheobronchial obstruction.

Causes of stridors(always need investigations):

1)Infection/inflammation, e.g. acute epiglottitis in young patients.

2)Tumours of the trachea and main bronchi or extrinsic compression by lymph nodes in older adults.

3)Rare causes include anaphylaxis and foreign body inhalation.

*Respiratory symptoms:

1)Cough

2)Wheezing

3)Stridors

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

Sputum ExpectorationSputum is mucus produced from the respiratory tract. The normal lung produces about 100 ml of clear sputum each day, which is transported to the oropharynx and swallowed.

Colour:

1) Clear or ‘mucoid’ sputum: is produced COPD with no active infection and asthma.

2) Yellow sputum: occurs in acute lower respiratory tract infection (live neutrophils) and in asthma (eosinophils).

3) Green purulent sputum (dead neutrophils) indicates chronic infection, e.g. bronchiectasis, because lysedneutrophils release the green-pigmented enzyme, verdoperoxidase.

4) Rusty red sputum : can occur in early pneumococcal pneumonia, as pneumonic inflammation causes lysis of red cells.

Amount (teaspoon or cups):

1)Large volumes of purulent sputum which varies with posture(leaning forward) suggest bronchiectasis. Suddenly coughing up large amounts of purulent sputum on a single occasion suggests rupture of a lung abscess or empyemainto the bronchial tree.

2)Moderate to large volumes of watery sputum with a pink tinge in an acutely breathless patient suggest pulmonary oedema but, if occurring over weeks, suggests alveolar cell cancer.

Taste or smell:

Foul-tasting or smelling sputum suggests anaerobic bacterial infection as in bronchiectasis, lung abscess and empyema. In bronchiectasis a change of sputum taste may indicate an infective exacerbation.

Solid materials:

Casts of the bronchi(asthma), necrotic tumour and inhaled foreign bodies, e.g. food, teeth and tablets.

*Respiratory symptoms:

1)Cough

2)Wheezing

3)Stridors

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

HaemoptysisHaemoptysis is coughing up blood from the respiratory tract and always requires investigation.Clarify whether the blood was coughed up from the

respiratory tract, vomited (GIT) or suddenly appeared in the mouth without coughing(nasopahryngeal).

Amount and appearance :1)Small amounts of blood streaks: most likely infection.2)Large amount of pure blood(frank) bronchiectasis,lungcancer,TB,wegner’s granulomatosis,aortobronchial fistula and lung abcess.

Duration and frequency:1)Recurrent chronic haemoptysis for prolonged period(months): suggest lung cancer or bronchiectasis.2)Acute single episode: most likely infection or lung infarction especially if associated with pleuritic chest pain and dyspnea.

*Respiratory symptoms:

1)Cough

2)Wheezing

3)Stridors

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

Dyspnea

• Is an excessive awareness of breathing &is normal in strenuous physical exercise .

Patient terms

Shortness of breath

Tiredness

Difficulty getting enough air in

Shortness of breathing

*Respiratory symptoms:1)Cough

2)Wheezing

3)Stridors

4)Sputum expectoration

5)Haemoptysis

6)Dyspnea

7)Chest pain

Chest Pain

1)Pleuritic chest pain

2)Chest wall pain

3)Mediastinal chest pain

Pleuritic chest pain:

Is a sharp stabbing pain and is intensified by inspiration or coughing caused by irritation of the parietal pleura.

Causes :

1)Infections as in pneumonia

2)Pulmonary infarction

3)Pneumothorax

4)Connective tissue diseases

Chest wall pain :

Usually localized and related to movement.

Causes :

1)Chronic cough

2)Rib fractures

3)Muscular pain

4)Bony metastasis

5)Herpes Zoster(shingles)

.Mediastinal chest pain:

It is central,retrosternal pain unrelated to respiration or cough.

Causes :

1)Acute MI

2)Pulmonary embolism

3)Oseophageal rupture

4)Aortic dissection

5)Mediastinitis and trachitis