Module 4

Mediastinum

contains all structures between the lungs and their pleural coverings

Where does the mediastinum extend from?

the sternum to the thoracic vertebrae and from the thoracic aperture
to the diaphragm

Pleura

reduces friction allowing respiration. Each lung covered by visceral
pleura inside the lung. Parietal pleura covers the outside of the lung

Potential space

where two pieces of tissue are pressed closely together. Obliterating
the actual space between the two

Endothoracic fascia

underneath all the intercostal muscle that provides a connective
tissue site, allowing the parietal pleura to attach to the chest wall.

Pleural sac

a potential space where the parietal pleura in "glued" by
serous fluid to the visceral pleura covering a lung

Transient

only lasting for a short time

Expansion of thoracic walls

increase chest volume and creates a transient negative pressure
within the pleural cavity. This is transferred to the visceral
pleura-covered lung, creating a negative pressure within the lungs.

Air at atmospheric pressure

flows into each lung and the lungs expand

What happens when the chest wall and parietal pleura move?

visceral pleura and lungs move

Root of the lung

point where visceral is continuous with parietal pleura

What does the root of the lung contain?

primary bronchus, pulmonary vessels, autonomic nerves, and lymphatic vessels

Parietal pleura is named

regionally for the wall that it covers

Costal pleura

lines the inside of the chest wall

Diaphragmatic pleura

lines the outside of the diaphragm
Ex: mediastinal and cervical pleura

Costodiaphragmatic recess

the inferior most portion of the pleura. Where pleural effusions occur.

In quiet respiration

the lung does not completely fill the pleural cavity so that an
inferior extension of the pleural cavity is formed below the lower
border of each lung. Here, the costal and diaphragmatic parietal
pleura are in contact.

Pleural effusion

accumulation of fluid in the pleural cavity that will compress a lung
and compromise respiration

Anteriorly, the costodiaphragmatic recess is located

between and sixth and eighth rib.
Laterally- 8th and 10th rib
Posteriorly- 10th and 12th rib

How is fluid withdrawn from a pleural cavity?

by introducing a needle (thoracentesis or pleural tap) through the
inferior part of an intercostal space adjacent to the
costodiaphragmatic recess.

When the chest wall expands and the diaphragm descends,

thoracic volume increases and thoracic pressure decreases allowing
air to enter each lung

How many lobes does the right lung have?

3

How many lobes does the left lobe have?

2

Why does the left lung have two lobes?

the last space is occupied by the heart

What are the lung lobes separated by?

oblique fissures

Right lung has __________ fissure

horizontal

Pulmonary arteries are the only arteries in the body that

carry deoxygenated blood. Sent into the lungs to be oxygenated and
carried out by the pulmonary veins

Pulmonary artery location

right anterior left superior in comparison to the main bronchus
branches of each lung

Where are pulmonary veins located?

anteriorly and inferiorly to both the bronchus and pulmonary arteries
in both lungs

Depressions at the top of the lungs are caused by

the azygous vein, esophagus, superior vena cava, and inferior vena
cava. Positioned more on the right side of the mediastinum

Phrenic nerve is coursing through

the anterior of the right lung

Right vagus nerve posterior to

right lung

Aortic arch/thoracic aorta and esophagus cause

depressions on left lungs. Phrenic nerve anterior, vagus nerve posterior