J Chapter 18: Thorax & Lungs

J Chapter 18: Thorax & Lungs

1. Name the components of the thoracic cage

   • Sternum 12 pairs of ribs 12 thoracic vertebrae

2. Describe the surface landmarks on the thorax.

   • Suprasternal notch - feel this hollow U-shaped depression just above the sternum in-between the clavicles
   • Sternum - breast bone that has three parts, manubrium, the body, and the xiphoid process
   • Sternal angle (angle of louis) - articulation of the manubrium and obeyed of the sternum, it is continuous with the second rib
   • Coastal angle - right and left coastal margins from an angle where they meet at the xiphoid process
   • Vertebra prominens - start here. flex your head and feel for the most prominent bony spur protruded at the base of the neck spinous process - count down these knows on the vertebrae which sack together to from the spinal column
   • Inferior border of the scapula - lower tip is usually at the seventh or eighth rib
   • Twelfth rib - palpate midway between the spine and the persons side to identify its free tip

3. List the contents of the mediastinum.

   • Esophagus, trachea, heart, and great vessels

4. Describe the borders of the lung.

   • The posterior border is smooth and rounded (in contrast to the anterior and inferior borders, which are sharp). It is formed by the costal and mediastinal surfaces meeting posteriorly. The lung root is a collection of structures that suspends the lung from the mediastinum.
   • In the anterior chest the apex of lung tissue is 3 to 4 cm above the inner third of the clavicles The base rests on the diaphragm at about the 6th rib in the midclavicular line Laterally lung tissue extends from the apex of the axilla down to the 7th or 8t rib Posteriorly the location of C7 mark the apex of the lung tissue and T10 usually correspond to the base

5. Describe the anatomic demarcation of the five lobes of the lungs

   • Right lung has 3 lobes: Superior, Middle, and Inferior lobe. Apex is nearest the head, and base is near the stomach (opposite of the heart's base and apex) Left lung has 2 lobes

6. Describe the pleurae and their function

   • Pleurae are serous membranes that form an envelope b/w the lungs and chest wall
   • Visceral pleura lines the outside of the lungs
   • Parietal pleura lining the inside of the chest wall and diaphragm

7. List the structures that compose the respiratory dead space

   • Dead spaces is space that is filled with air but is not available for gaseous exchange
   • about 150ml in the adult
   • Trachea and bronchi

8. Discuss the location and functions of the trachea and bronchial tree.

   • The tubes that make up the bronchial tree perform the same function as the trachea: they distribute air to the lungs. The alveoli are responsible for the primary function of the lungs, which is exchanging carbon dioxide and oxygen.
   • Trachea lies anterior to the esophagus and is 10 to 11 cm in length, begins at cricoid cartilage in the neck

9. Summarize the mechanics of respiration.

   • Normally, our breathing pattern changes without our awareness in response to cellular demands. This involuntary control is mediated by the respiratory centre in the brainstem (pons and medulla). The major feedback loop is humoral regulation, or the change in carbon dioxide and oxygen levels in the blood, and less, importantly, the hydrogen ion level. Normal stimulus to breathe for most of us is an increase of carbon dioxide in the blood, or hypercapnia.

10. Discuss developmental care associated with the thoracic cavity.

    • Coastal cartilages become calcified thus thorax is less mobile, muscle strength declines
    • Small airway closure which yields a decreased vital capacity and increased residual volume
    • With aging, histologic changes occur therefore there is less surface area available for gas exchange