Lungs

Dr. Sama ul Haque

Objectives

Define mediastinum.

Discuss the anatomical structure of lungs.

Enlist the relations of right and left lungs.

Give the blood and nerve supply of the lungs.

Mediastinum

Definition:

A median septum or median partition between the two pleural cavities.

Superior boundary:Superior thoracic apertureInferior boundary:DiaphragmAnterior boundary: SternumPosterior boundary:Bodies of vertebrae T1 to T12Lateral boundaries: Mediastinal parietal pleura(left and right).

Boundaries of the Mediastinum

Gross Anatomy of the Lungs

Each lung has a conical shape, concave base rests upon

the muscular diaphragm.

Its superior region is called Apex.

Toward the midline, the lungs are separated from each

other by the Mediastinum.

The relatively broad, rounded surface in contact with

the thoracic wall is called the Costal surface of the

lung.

LungsLeft lung

divided into 2 lobes by oblique fissure

smaller than the right lung.

cardiac notch accommodates the heart

Right Lung

divided into 3 lobes by oblique and horizontal fissure

Lungs and Pleura

(Anterior view)

Lungs and Pleura

(Posterior view)

Lungs An apex A base 3 borders:

Anterior Posterior Inferior

2 surfaces: Medial and costal.

Medial surface: Mediastinal & vertebral

Apex And Base of the lung Apex: It extends up 1 inch

above and behind the medial third of the clavicle.

Base: It is concave in shape .It is related to:1- Diaphragmatic pleura.2- Right copula of the

diaphragm.3- Liver (right lung) . Liver, stomach (fundus),

and spleen (left lung).

Borders of the lungA. Anterior border

It is a sharp border. The lower part of the anterior border of the left lung contains the cardiac notch (just below the cardiac notch there is a projection called the lingula).

B. Posterior border

It is a rounded border.

C. Inferior border

Lobes &Fissures of the lungs

Three lobes: Superior Middle Inferior

Fissures: Oblique fissure Transverse fissure

Two lobes Superior Inferior

Fissure: Oblique fissure

Right lung Left lung

Lobes and fissures of Lungs

Mediastinal Surface of the Right Lung Cardiac impression (Right atrium). Superior vena cava. Inferior vena cava. Right subclavian artery. Right brachiocephalic vein Azygos vein. Esophagus. Trachea. Thymus

Mediastinal Surface of the Left Lung Cardiac impression (Left ventricle). Arch of Aorta. Descending aorta. Left subclavian artery. Left brachiocephalic vein Thoracic duct. Esophagus. Trachea. Thymus

Hilum of the lungsIt gives passage to the It gives passage to the

structures forming the structures forming the Root of the lung.

1. Bronchus2. Pulmonary artery3. Pulmonary veins4. Hilar lymph nodes.5. Bronchial vessels. 6. Pulmonary plexuses 7. Pulmonary ligament

Hilum of left lung

Hilum of right lung

Difference between the right and left lungs

Right Lung Left Lung

Size and weight Larger and heavier Smaller and lighter

Length and breadth Shorter and wider Longer and narrower

LobesFissures

ThreeTwo

Two lobes One fissure

Anterior border No cardiac notch Cardiac notch and lingula.

Bronchial

Tree

Bronchopulmonary Segments

Bronchopulmonary Segments

Respiratory Bronchioles, Alveolar Ducts, and Alveoli

Lungs contain small sacs called alveoli.

They have a thin wall specialized to promote

diffusion of gases between the alveolus and

the blood in the pulmonary capillaries.

Respiratory Bronchioles, Alveolar Ducts, and Alveoli

Gas exchange can take place in the respiratory

bronchioles and alveolar ducts as well as in the

alveoli, each lung contains approximately 300

to 400 million alveoli.

The spongy nature of the lung is due to the

packing of millions of alveoli together.

Respiratory Bronchioles

Alveolar Ducts

And

Alveoli

Blood supply of Lungs

Pulmonary circulation:

Bronchial circulation:

Bronchial arteries supply oxygenated blood to lungs, bronchial veins carry

away deoxygenated blood from lung tissue.

Pulmonary Circulation

Nerve supply

Anterior and posterior pulmonary plexuses.

a. Sympathetic component:

(T2 to T5 sympathetic ganglia).

b. Parasympathetic component (vagi)

Thank YouThank You