Lung Lobes, Structure, and Identification

Okay, here are the updated study notes, incorporating the new information provided:

Lung Lobes and Structure

• Lungs have lobes, which are separate parts with their own blood and nerve supply.
• Lungs also have bronchopulmonary segments, allowing removal of a segment without affecting others.
• The left lung has two lobes, while the right lung has three lobes.
• The left lung has two lobes due to the heart projecting over to the left side, taking up space.
• The lobes have separate blood vessels and airways; if a blood clot clogs an artery to one lobe, other lobes can still function.
• The left lung has a superior (upper) lobe and an inferior (lower) lobe, split by the oblique fissure.
• The right lung has an upper, middle, and lower lobe with an oblique and horizontal fissure.
• Horizontal fissures are not always well-defined in cadavers.

Lung Identification and Location

• The shape of the lung is a key indicator: look for the apex (top), base (diaphragm side), costal surface (rounded, rib side), and mediastinal surface (next to the mediastinum).
• The apex of the lung extends above the first rib, making it vulnerable to injuries in the shoulder area.
• The liver pushes up under the right lung, limiting lung expansion on that side.
• The anterior edge of the lung is very thin, filling space between the heart and thoracic cage.
• The cardiac notch and lingula (tongue-like projection) are features of the left lung, accommodating the heart.

Examining the Lungs

• The upper lobe of the left lung can be heard on the anterior chest.
• To hear the lower lobe of the left lung, listen laterally, posteriorly, and low down on the chest.
• The lungs are covered in visceral pleura, while the thoracic cage is lined with parietal pleura, forming a continuous, airtight membrane.
• The horizontal fissure of the right lung is around nipple level (fourth intercostal space).
• Anterior to the horizontal fissure on the right lung is the middle lobe and inferior-posterior is the lower lobe

Lung Surfaces and Hilum

• The base of the lung is the domed surface that sits on the diaphragm.
• The costal surface shows impressions from the ribs.
• The hilum (root) of the lung is where the parietal and visceral pleura meet, containing pulmonary arteries, pulmonary veins, and airways.
• Pulmonary arteries carry deoxygenated blood from the heart to the lungs
• Pulmonary veins carry oxygenated blood from the lungs to the heart.
• During gaseous exchange in the lungs, hemoglobin changes and becomes bright red
• The heart and great vessels are located within the mediastinum, a connective tissue space in the thorax.
• The mediastinal surface of the lung is where the mediastinum meets the pleura.

Hilum Structures and Orientation

• The pulmonary trunk splits into the left and right pulmonary arteries.
• Blood returns from the lungs to the left atrium via pulmonary veins.
• The trachea is posterior to the blood vessels.
• The bronchus is posterior to the pulmonary artery and vein.
• Pulmonary artery branches superiorly at the hilum.
• Pulmonary vein branches inferiorly at the hilum.
• The left main bronchus is located in the middle and posteriorly at the hilum.