Chapter 4 Respiratory System

1. Chapter 4Respiratory System

2. Respiratory System • Consists of the respiratory and conducting parts • Respiratory part • Site of gas exchange • Consists of bronchioles, alveolar ducts, and alveoli • Conductingpart • Provides rigid conduits for air to reach the sites of gas exchange • Includes all other respiratory structures (e.g., nose, nasal cavity, pharynx, trachea) • Respiratory muscles: diaphragm and other muscles that promote ventilation

3. Major Functions of the Respiratory System • To supply tissues with oxygen and dispose of carbon dioxide • Respiration: four distinct processes must happen • Pulmonary ventilation:moving air into and out of the lungs • External respiration: gas exchange between the lungs and the blood • Internal respiration: gas exchange between blood and tissues • Transport: transport of oxygen and carbon dioxide between the lungs and tissues

4. General Anatomy • Upper respiratory tract: • The nose, Mouth, pharynx, and Larynx. • Lower respiratory tract: • The trachea, Bronchi, Alveoli, and Lungs. • The thoracic cavity consists of: • Right and left pleural cavities (the parietal pleura lines the thoracic cavity, and the visceral pleura adheres directly to the lung tissue. • Mediastinum.

5. Respiratory Zone • Begins as terminal bronchioles, feed into respiratory bronchioles. • Respiratory bronchioles lead to alveolar ducts, then to terminal clusters of alveolar sacs composed of alveoli • Approximately 300 million alveoli: • Account for most of the lungs’ volume • Provide great surface area for gas exchange

6. Respiratory Zone

8. Gross Anatomy of the Lungs • Lungs occupy all of the thoracic cavity except the mediastinum • Root or Hilum: site of vascular and bronchial attachments • Costal surface: anterior, lateral, and posterior surfaces in contact with the ribs • Apex: narrow superior tip • Base: inferior surface that rests on the diaphragm

10. Hilum of the lungs

11. Blood Supply to Lungs • Lungs are perfused by pulmonary and bronchial arteries. 1- Pulmonary arteries: • Supply systemic venous blood to be oxygenated • Ultimately feed into the pulmonary capillary network surrounding the alveoli • Pulmonary veins: carry oxygenated blood back to the heart 2- Bronchial arteries: • Provide systemic blood to the lung tissue • Arise from aorta and enter the lungs at the hilum. • Supply all lung tissue except the alveoli

13. Pleurae • Thin, double-layered serosa • Parietal pleura • Covers the thoracic wall and superior face of the diaphragm • Continues around heart and between lungs • Visceral pleura • Covers the external lung surface • Divides the thoracic cavity into three chambers • The central mediastinum • Two lateral compartments, each containing a lung

14. Mediastinum • Divided into: anterior, middle, and posterior portions. • Anterior mediastinum contains: the thyroid and thymus glands. • Middle mediastinum contains: heart and great vessels, esophagus, and trachea. • Posterior mediastinum contains: descending aorta and spine.

15. Imaging techniques used to investigate chest pathology include: • Plain X-Ray film • Computed Tomography (CT Scan) • Magnetic Resonance Imaging (MRI) • Ultrasound (US) • Angiography Chest X-Ray Review

16. Radiographic signs • Silhouette sign: opacity near the heart so you can not detect the heart boarder easily. • Notes from the radiographs: opacity frontal and heart frontal so lesion is frontal.

17. Negative Silhouette • Lesion Posterior.

18. Q. Lesion anterior or posterior?

19. Air Bronchogram • Opacity in the lung contains a tree filled with air (bronchi contains air but alveoli opaque). • Lesion arises from the lung not chest wall or pleura or mediastinum. • Air bronchogram=alveolar pathology=consolidation (lung filled with liquid).

20. Pulmonary nodule: well defined lesion less than 3cm. • Mass: well defined lesion more than 3cm.

21. To interpret chest x-raydifferentiate between • Focal lesion • Diffuse lesion

22. Focal lesions • Nodules • Masses • Cavities: well defined lesion (sphere-shape) filled totally with air or partially (air+liquid). • Patches: ill defined lesion (opacity) contains air bronchogram.

24. Nodules maybe due tomost common • Tuberculoma • Hamartoma • Bronchogenic carcinoma • Metastases (multiple nodules or solitary) • AVM (Arterio-Venus Malformation). • Hydatid cyst

25. Benign nodule (Hamartoma and Tuberculoma): If we have pulmonary nodule and the edge is smooth and contains calcification. A.V.M. bilateral

26. Lung Tubercloma: The term tuberculoma of the lung is used here to describe a rounded, homogeneous radiographic opacity, with well-defined borders, one centimetre or morein diameter.

27. How we can differentiate? • Tubercluma: usually single, smooth edge, calcified, less than 3 cm. • Hamartoma: usually single, smooth edge, popcorn calcification, less than 3 cm. • AVM: nodule connected to the hilum by feeding artery and draining vein.

28. Hamartoma: is a benign, focal malformation that resembles a neoplasm in the tissue of its origin. This is not a malignanttumor, and it grows at the same rate as the surrounding tissues. It is composed of tissue elements normally found at that site, but which are growing in a disorganized mass. They occur in many different parts of the body and are most often asymptomatic and undetected unless seen on an image taken for another reason • Lung Hamartoma: The most common hamartomas occur in the lungs. About 5–8% of all solitary lung nodules, about 75% of all benign lung tumors, are hamartomas.

29. Lung HamartomaBenign nodule is characterized by the presence of calcium but the presence of calcium in the mass can not be considered as a sign of benign lesion.

30. Bronchogenic carcinoma • Speculated margin nodule= malignancy. • Upper lobe distribution 70%.

31. Bronchogenic carcinoma • Lateral view showing the speculated margin.

32. Hydatid cyst • Single or multiple lesions filled with water. • Thin non enhancing margin. • Abscess: thick enhancing margin, usually contains air.

33. X- ray lung abscess

34. CT is needed to show if the lesions are cystic or solid

35. Patch • An ill defined lesion with air bronchogram. • Air bronchogram: air filled bronchi passing through opaque lung. • Pulmonary lesion. • Alveolar pathology. • Consolodation. • Patch may be due to: • Pneumonia or infarction.

36. Pneumonia • is an inflammatory condition of the lung affecting primarily alveoli. • It is usually caused by infection with viruses or bacteria. • Typical symptoms include a cough, chest pain, fever, and difficulty breathing

37. Pneumonia is accompanied by Consolidation

38. Diffuse lung disease • We have 4 radiographic pattern: • Reticular pattern e.g. Pneumonia, Bronchitis: Confluent small ill-defined densities produce a reticular pattern.

39. 2. Ground glass pattern: increase in density in areas of ground glass and air trapping in lower lobes in patients with hypersensitivity pneumonitis (inflammation of lung tissue). Pneumonia is pneumonitis combined with consolidation (is a region of (normally compressible) lung tissue that has filled with liquid) due to infection.

40. 3. Cystic lesions: air filled cysts.

41. 4. Nodular pattern