Lungs Pleural Cavities and Respiratory Muscles

What is the basic function of the lungs?

Conduct air to alveoli and allow gas exchange

Where are the lungs located?

In the thoracic cavity within pleural membranes

What is the shape and position of the lungs?

Cone-shaped with apex under clavicle and base resting on diaphragm

What is the hilum of the lung?

Medial region where bronchi, blood vessels, nerves, and lymphatics enter/exit

How many lobes does the right lung have?

Three: superior, middle, and inferior

How many lobes does the left lung have?

Two: superior and inferior, with cardiac notch

What is the cardiac notch?

Medial depression in the left lung to accommodate the heart

What are bronchopulmonary segments?

Subdivisions of lobes, each served by a tertiary bronchus; 10 in right, 8–9 in left lung

What is a lobule in the lung?

Smallest visible lung subdivision, each containing a bronchiole and its branches

What are the pleural cavities?

Serous membrane cavities that isolate and protect the lungs in the thoracic cavity

What is the parietal pleura?

Outer membrane lining thoracic wall, diaphragm, and mediastinum

What is the visceral pleura?

Inner membrane directly attached to the lung surface

What is the pleural cavity?

Space between pleural membranes filled with pleural fluid, maintained at low pressure

What are the functions of the pleural cavity?

Reduces friction, isolates lungs, assists in ventilation

What are the respiratory muscles?

Skeletal muscles around the thoracic cavity responsible for ventilation

What are the primary inhalation muscles?

Diaphragm and external intercostals

What are the primary exhalation muscles?

None – exhalation at rest is passive

What muscles assist in forceful inhalation?

Sternocleidomastoid, scalenes, pectoralis minor, serratus anterior

What muscles assist in forceful exhalation?

Internal intercostals, transversus thoracis, rectus abdominis