Anatomy Review: Respiratory Structures
Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings
Page 1. Introduction
• As they function, our cells use oxygen and produce carbon dioxide.
• The respiratory system brings the needed oxygen into and eliminates carbon dioxide from the body by
working closely with the cardiovascular system. • The blood transports these gases, carrying oxygen to the tissues and carbon dioxide to the lungs.
Page 2. Goals
• To review the major organs of the respiratory system.
• To examine the structures of the respiratory zone of the lungs.
• To explore the microscopic anatomy of an alveolus.
Page 3. Overview: Respiratory System Organs • Let's review the organs of the
respiratory system by following the
flow of air.
• Air enters the nose by passing
through two openings called the
external nares, or nostrils.
• Within the nose, the air passes
through the nasal cavity, and then
travels through the pharynx, a
muscular tube which carries both
food and air throughout most of its
• Air then enters the larynx.
• After passing through the larynx,
air enters the trachea, which is held
open by incomplete rings of cartilage. • The trachea divides into a right and
a left primary bronchus, which carry the air into the lungs. • Although not part of the respiratory system, the diaphragm and the intercostal muscles play important roles
• Label the diagram:
Page 4. Demonstration of Pleurae and
• Each lung is surrounded by two layers of
serous membrane known as the pleurae.
• The relationship between the pleurae and the lungs can be demonstrated by pushing a fist
into a water-filled balloon. The balloon represents the pleurae, and the fist represents the lung.
• As the fist pushes into the balloon, notice how the balloon wraps around it, and the opposite surfaces of the
balloon almost touch.
• The inner part of the balloon which wraps around the fist represents the visceral pleura. The visceral pleura is the part of the pleura which covers the surface of the lungs.
• The outer part of the balloon represents the parietal pleura, which lines the mediastinum, the diaphragm,
and the thoracic wall.
• Notice that the visceral and parietal pleurae are actually a continuation of the same membrane. • The water-filled space between the two layers represents the pleural cavity, which contains pleural fluid.
Page 5. Visceral and Parietal Pleura
• The visceral pleura and parietal pleura enclose each lung in a separate sac. The frosty layer you see here
covering the lung is the portion of the parietal pleura that lines the anterior thoracic wall.
• The visceral pleura covers the surface of the lungs and the cut edges of the parietal pleura.
• The pleural cavity is an extremely thin, slit-like space between the pleurae, separating them by a thin layer
of pleural fluid. The pleural fluid assists in breathing movements by acting as a lubricant.