THE LUNGS

lungs

. The —-- occupy the entire thoracic cavity except for the most central area

apex

The narrow, superior portion of each lung.

base

The broad lung area resting on the diaphragm.

left lung

which part of the lung has two lobes.

right lung

which part of the lung has three lobes.

visceral pluera

The surface of each lung is covered with a visceral serosa called the pulmonary, or ——

parietal pleura

the walls of the thoracic cavity are lined by the ——.

pleural fluid

a slippery serous secretion which allows the lungs to glide easily over the thorax wall during breathing movements and causes the two pleural layers to cling together.

pleural space

The lungs are held tightly to the thorax wall, and the —— is more of a potential space than an actual one.

bronchioles

The smallest of the conducting passageways are the ——.

alveoli

The terminal bronchioles lead to the respiratory zone structures, even smaller conduits that eventually terminate in —— , or air sacs.

respiratory zone

which includes the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli, is the only site of gas exchange.

conducting zone structure

serves as conduits to and from the respiratory zone.

stroma

The balance of the lung tissue, its ——, is mainly elastic connective tissue that allows the lungs to recoil passively as we exhale.

alveolar pores

connecting neighboring air sacs and provide alternative routes for air to reach alveoli whose feeder bronchioles have been clogged by mucus or otherwise blocked.

respiratory membrane

Together, the alveolar and capillary walls, their fused basement membranes, and occasional elastic fibers construct the —— (air-blood barrier), which has gas (air) flowing past on one side and blood flowing past on the other.

alveolar macrophages

sometimes called “dust cells”, wander in and out of the alveoli picking up bacteria, carbon particles, and other debris.

cuboidal cells

scattered amid the epithelial cells that form most of the alveolar walls are chunky ——-.

surfactant

a lipid (fat) molecule called ——-, which coats the gas exposed alveolar surfaces and is very important in lung function.