Lungs & Superior Mediastinum

Question 1

superior mediastinum

Answer 1

above sternal angle (about t4 vertebrae)

Lies immediately post. to the manubrium of the sternum

Superior 1/2 of thymus found here

esophagus posterior to trachea

Question 2

inferior mediastinum

Answer 2

below sternal angle (about t4 vertebrae)

Divisions: anterior, middle, posterior

Question 3

pleural cavities

Answer 3

-houses lungs
-superiorly extend above rib 1 into root of neck
-inferiorly extend to just above costal margin
-medial wall is mediastinum

Question 4

Lung boundaries

Answer 4

-Superiorly, extend above rib 1 into root of the neck
-medial wall of each if the mediastinum
-inferiorly extend to alevel just above costal margin
T10 posteriorly
T8 midaxillary line
T6 midclavicular line
-* lung is about 2 rib levels above the pleura

Question 5

Serous membranes of thoracic viscera

Answer 5

Viscera covered with serous membrane
1. Parietal layer- lines walls of cavity
2. Visceral layer- adheres to surface of organ

Small layer of serous fluid between parietal & visceral layer (reduces friction)

Question 6

Pariteal pleura

Answer 6

Covers walls of the pleural cavity
1) costal part
2) diaphragmatic part
3) mediastinal part
4) cervical part

Question 7

visceral pleura

Answer 7

covers surface of lung

Question 8

pleural cavity

Answer 8

space betweeen parietal & visceral layers
- thin layer of serous fluid

Question 9

Pleural recesses

Answer 9

reflection points at which lung does not fully extend into the pleural space. formed of two layerings of parietal pleura.
-Costomediastinal recess (medial)
-Costodiaphragmatic recess (lower corners)

Question 10

Clinical correlation- collapsed lung- penetrating wound

Answer 10

• air will be sucked into the pleural cavity because of the negative pressure
• surface tension adhering visceral to parietal pleura will be broken
• lung will collapse, expelling most of its air because of its inherent elasticity
• when a lung collapses, the pleural cavity (normally a potential space) becomes a real space (in which blood and fluid can enter)

Question 10

hydrothorax (pleural effusion)

Answer 10

entry of fluid into pleural cavity

Question 10

pneumothorax

Answer 10

entry of air into pleural cavity

Question 11

hemothorax

Answer 11

entry of blood into pleural cavity

Question 11

structures within each root of the lung

Answer 11

• 3 lobes on right, 2 lobes on left
• Vagus n. passes posterior to root of lung
• phrenic n. passes anterior

Question 12

Root of lung

Answer 12

• tubular collection of structures that attach to structures in mediastinum
• enclosed in pleural sleeve- continuation between visceral and parietal pleura
• Contents: pulmonary artery, pulmonary veins (2), main bronchus, bronchial vessels, nerves, lymphatics

Question 13

pulmonary ligament

Answer 13

formed by 2 layers of visceral pleura coming together

Question 14

hilum of lung

Answer 14

-wedge-shaped area on teh mediastinal surface of each lung through which structures in teh root enter or exit the lung
-“door way”
-Contents: pulmonary artery (there can appear to be 2 depending on cut), pulmonary veins (2), bronchus, bronchial vessels, nerves, and lympathics

Question 15

R vs. L lung mediastinal surface

Answer 15

R.A.L.S (right, anterior) (left superior) for positioning of pulmonary arteries

“You put the LEFT OVERS, int the fridge RIGHT in FRONT”

Question 16

pulmonary aa.

Answer 16

-Deoxygenated blood from heart
- Give rise to lobar and segmental aa.

Question 17

pulmonary vv.

Answer 17

-oxygenated blood to heart
-formed by lobar and segmental vv.

Question 18

Right lung mediastinal surface

Answer 18

-SVC impression
-Cardiac impression
-Horizontal fissure
-IVC impression
-Brachiocephalic impression
-Esophagus impression
-Arch of azygos impression
-Esophagus impression
-Oblique fissure

Question 19

Left lung mediastinal surface

Answer 19

-Arch of aorta impression
-Thoracic impression
-left subclavian a. impression
-cardiac impression
- oblique fissure
- lingula (middle lobe if it were to have developed)
-Cardiac notch

Question 20

Bronchial tree

Answer 20

-Trachea (extends from C7-T4/5)
-Right and left main bronchi (primary)–> right is wider & more vertical than left
-Lobar bronchi (secondary)–> supplies a lobe
-Segmental bronchi (tertiary)–> supplies bronchopulmonary segments

Question 21

Bronchial tress flow chart

Answer 21

main (primary) bronchi –> lobar (secondary) bronchi –> segmental (tertiary) bronchi –> lots of branching (smaller & smalelr diameter tube; less cartilage; more smooth muscle) –> bronchioles (1 mm or less) –> lots of branching –> terminal bronchioles –> respiratory bronchiole –> alveolar duct –> alveolar sac –> alveoli

Question 22

When you start to lose cartilage on the bronchial tree, what do you gain?

Answer 22

surfactant

Question 23

Bronchopulmonary segment

Answer 23

area of lung supplied by segmental bronchus and its’ accompanying pulmonary a. branch

Question 24

bronchial aa.

Answer 24

originate from thoracic aorta or one of tits branches

Question 25

bronchial vv.

Answer 25

-drain into either pulmonary vv. or left atrium
-azygous v. on the right or superior intercostal v.
- hemiazygos v. on the left

Question 26

lymphatic drainage

Answer 26

-both superficial and deep drain into superior and inferior trachobronchial nodes
-left inferior lobe drains into right superior traceobronchial nodes

Question 27

subpleural lymphatic plexus

Answer 27

lies deep to visceral pleur and drians the lung parenchyma (tissue)

Question 28

bronchopulmonary lymphatic plexus

Answer 28

located in the submucosa of the bronchi and peribronchial CT and draining structures from the root of the lung

Question 29

Innervation of the lungs

Answer 29

Anterior & posterior pulmonary plexus
-postsynaptic sympathetic fibers form paravertebral ganglia (dilates bronchioles)
-presynaptic parasympathetic fibers from vagus nn. (constricts bronchioles)