Lecture 12: Mediastinum

Question 1

Describe the superior mediastinum

Answer 1

The region SUPERIOR to the horizontal line running from the sternal angle to the T4 vertebra

Question 2

What is found in the superior mediastinum (8 things)

Answer 2

Thymus
Great vessels
Trachea
Esophagus
Thoracic duct
Phrenic nerves
Vagus nerves
Sympathetic trunks

Question 3

Describe the inferior mediastinum

Answer 3

Region inferior to the line from the sternal angle to the T4 vertebra

Question 4

What is the inferior mediastinum bound by (inferiorly)

Answer 4

Diaphragm

Question 5

Describe the anterior mediastinum

Answer 5

Sternum to pericardial sac

Question 6

What is found in the anterior mediastinum?

Answer 6

Thymus and/or adipose tissue

Question 7

What is found in the middle mediastinum?

Answer 7

Pericardium and heart

Question 8

What is found in the posterior mediastinum?

Answer 8

Pericardial sac - thoracic vertebrae

Question 9

What are the contents of the posterior mediastinum?

Answer 9

Esophagus
Thoracic duct
Aorta (descending thoracic)
Azygos (& hemi) veins
Nerves (sympathetic trunk, vagus)

Question 10

What is the bilobed organ found in the superior mediastinum?

Answer 10

Thymus

Question 11

What is the importance of the thymus

Answer 11

Site for T-lymphocyte maturation and differation

Question 12

After puberty, what happens to thymus?

Answer 12

Replaced with adipose tissue

Question 13

Where does the trachea split into L/R primary bronchi?

Answer 13

Level of sternal angle

Question 14

What is the fibromuscular tube found in the mediastinum?

Answer 14

Esophagus

Question 15

What are the three constrictions in the esophagus?

Answer 15

Arch of aorta
Left primary bronchus
Diaphragm

Question 16

Why would these esophageal constrictions be important to know? What is their clinical significance?

Answer 16

Individuals with swallowing problems likely will experience blockage/greatest difficulty along these three constrictions
If something (like a large pill) gets lodged in the esophagus, it is most likely to get lodged in one of these three constrictions

Question 17

What comes off of the aortic arch?

Answer 17

Brachiocephalic artery
Left common carotid artery
Left subclavian artery
(ABCS)

Question 18

What comes off the brachiocephalic artery?

Answer 18

Right common carotid artery
Right subclavian artery

Question 19

What comes off the descending thoracic aorta?

Answer 19

Posterior intercostal arteries
Bronchial arteries
Esophageal arteries

Question 20

What are the important veins of the mediastinum?

Answer 20

Left/Right brachiocephalic veins
SVC
IVC
Azygos vein
Hemiazygos vein

Question 21

What nerves are found anterior to the root of the lung

Answer 21

Phrenic nerves

Question 22

What nerve is found along the fibrous pericardium?

Answer 22

Phrenic

Question 23

What nerve is posterior to the root of the lung

Answer 23

Vagus

Question 24

What nerve comes off of vagus?

Answer 24

Reccurent Laryngeal Nerves

Question 25

Thoracic splanchnic nerves come from

Answer 25

Sympathetic trunks

Question 26

What are the thoracic splanchnic nerves?

Answer 26

Greater, lesser, & least

Question 27

What are the two major lymphatic structures of the mediastinum

Answer 27

Thoracic duct R. Lymphatic duct

Question 28

Define lymph

Answer 28

Fluid from arterioles/capillaries enters the extra-cellular space. This fluid will collect large proteins and other cellular junk. (AKA - material that is unable to pass through the walls of veins)

Question 29

What structures collect lymph and carry it from the tissues into progressively larger vessels?

Answer 29

Lymphatic vessels

Question 30

T/F: Lymph vessels do not have veins

Answer 30

False

Question 31

Where do lymph vessels lead to?

Answer 31

Lymph nodes

Question 32

What happens when lymphocytes encounter antigens?

Answer 32

They multiply and produce antibodies, this will enlarging the node.

Question 33

Lymph from the lower limb and abdomen/pelvis goes where?

Answer 33

Cisterna chyli

Question 34

What is the flow of lymph from the cisterna chyli?

Answer 34

Thoracic duct --> left subclavian vein

Question 35

Where does the thoracic duct orginate?

Answer 35

In the abdomen at cisterna chyli

Question 36

The right lymphatic duct drains lymph from

Answer 36

Right upper limb, neck, and head

Question 37

What's the innervation of the thoracic viscera?

Answer 37

ANS vis cardiac plexus

Question 38

What pathway of ANS does the thoracic viscera follow?

Answer 38

Pathway/Option 2

Question 39

What is the vascular supply to the lungs

Answer 39

I. Pulmonary system II. Bronchial (systemic) system

Question 40

Describe the pulmonary system (vascular supply) to the lungs

Answer 40

Blood to/from lungs for reoxy

Question 41

Describe the bronchial (systemic) system to the lungs

Answer 41

Supply bronchi and larger bronchioles

Question 42

Where do bronchial arteries branch from?

Answer 42

Thoracic aorta

Question 43

Describe bronchial veins

Answer 43

They drain into the azygos vein or accessory hemiazygos vein - sometimes drain into pulmonary veins

Question 44

Describe the lymphatics of the lungs

Answer 44

Lymph from bronchopulmonary lymph nodes goes to the tracheobronchial lymph nodes then to L/R bronchomediastinal lymph trunks and finally to right lymphatic duct or thoracic duct

Question 45

What supplies innervation to the lungs?

Answer 45

ANS

Question 46

What is the pulmonary plexus?

Answer 46

Nerves that consist of sympathetic and parasympathetic axons

Question 47

What is the parasympathetic innervation to the lungs?

Answer 47

CN X - Vagus

Question 48

What is the main function of CN X in the lungs

Answer 48

Bronchoconstrictor

Question 49

What is the sympathetic innervation of the lungs

Answer 49

T1-T5

Question 50

What is the main function of lung sympathetic innervation

Answer 50

Bronchodilator

Question 51

What ANS component is believed to be the cause of referred visceral pain (referred pain)

Answer 51

Afferent component

Question 52

Define referred visceral pain

Answer 52

visceral pain not felt in the viscera itself, but in a dermatome supplied by the same segments of the spinal cord

Question 53

Visceral pain for stomach

Answer 53

Epigastrum (T5-T9)

Question 54

Visceral pain for appendix

Answer 54

Umbilicus (T10)

Question 55

Visceral pain for heart

Answer 55

Upper left part of trunk (T1-T5)