Lecture 9 (mediastinum) pt 1

Question 1

How does blood enter and exit the left side of the heart?

Answer 1

Enter: Pulmonary veins
Exit: Aorta

Question 2

How does blood enter and exit the right side of the heart?

Answer 2

Enters: SVC and IVC
Exits: Pulmonary artery

Question 3

Thoracic cavity surrounded by the thoracic wall, diaphragm to superior thoracic aperture. What are the two cavities within it?

Answer 3

1) Central mediastinal cavity
2) Right and left pulmonary cavities

Question 4

What is within the central mediastinal cavity?

Answer 4

Pericardium, pericardial cavity, heart & great vessels, trachea, esophagus

Question 5

What two things are within the right & left pulmonary cavities?

Answer 5

Lungs and the pleural cavities

Question 6

What two things make up the pleural cavities? Describe what each covers and reflects

Answer 6

1) Parietal pleura: covers walls, diaphragm & reflects onto the root of the lungs and mediastina
2) Visceral pleura: covers viscera and reflects into the fissures

Question 7

1) What is the central compartment of the thoracic cavity?
2) What pleura are found here?
3) What thoracic viscera does this compartment contain?

Answer 7

1) Mediastinum
2) Mediastinal pleura
3) All the viscera in thorax except lungs

Question 8

What are the inferior and superior borders of the mediastinum called? What makes up the inferior part?

Answer 8

1) Superior thoracic aperture
2) Inferior thoracic aperture: diaphragm

Question 9

The sternum/costal cartilage of the mediastinum are found ____________________ to thoracic vertebral bodies

Answer 9

anteriorly

Question 10

1) Where are the anterior and posterior boundaries of the superior mediastinum?
2) Where is the transverse thoracic plane?

Answer 10

1) Superior thoracic aperture (first rib, clavicle, & jugular notch) to sternal angle anteriorly; to T5 posteriorly.
2) Runs anterior-posterior horizontally, from sternal angle anteriorly to superior endplate of T5 posteriorly

Question 11

1) What are the boundaries of the inferior mediastinum?
2) What further divides the inferior mediastinum?

Answer 11

1) Transverse thoracic plane superiorly, to diaphragm
2) Pericardium

Question 12

What are the 3 divisions of the inferior mediastinum, and what do they contain?

Answer 12

1) Anterior mediastinum: clear space
2) Middle mediastinum: heart
3) Posterior mediastinum: esophagus and descending thoracic aorta

Question 13

True or false: apex of lungs extends above clavicles

Answer 13

True

Question 14

Why is the diaphragm higher on the right side?

Answer 14

To make room for the liver

Question 15

Describe the esophageal plexus of nerves:
1) What is it made up of?
2) What does it modulate?

Answer 15

1) Made up of postsynaptic sympathetic and presynaptic parasympathetic fibers
2) Gives branches to the esophagus to modulate the enteric nervous system (smooth muscles of GI viscera)

Question 16

What does the cardiopulmonary plexus supply?
Where does it go?

Answer 16

1) To the heart itself and smooth muscles of airways
2) Follow vessels through the hilum as part of the root of the lung

Question 17

What does the vagus nerve do once it gives off the left and right recurrent laryngeal nerves? (3 things)

Answer 17

1) Forms net around trachea as a part of pulmonary plexus and around esophagus as part of esophageal plexus
2) Then anterior and posterior vagus nerves form vagal trunk at the esophageal hiatus (along with sympathetic fibers)
3) Goes into esophagus, bronchial smooth tissue, and cardiac muscle

Question 18

What does the pericardium fuse with?

Answer 18

Tunic adventitia

Question 19

What is the pericardium (pericardial sac)?
What does it enclose? (2 things)

Answer 19

Double walled fibro-serous membrane that encloses:
1) Heart
2) Roots of the Great vessels (fuses with tunica adventitia)
(similar to pleura enclosing the lungs)

Question 20

1) What is the outside layer of the pericardial sac? What does it blend with?
2) What is the internal surface of the external layer made of? What is it also called?
3) What is it reflected on the heart and great vessels as?

Answer 20

1) Fibrous (external layer) pericardium; blends with central tendon.
2) Serous membrane; parietal layer of serous pericardium
3) Visceral layer of serous pericardium

Question 21

What are the two layers of the serous (inner) layer of the pericardial sac, and what are they attached to?
What is between them?

Answer 21

1) Outer parietal layer: adhered to the fibrous layer
2) Inner visceral layer: adhered to the heart, aka epicardium
Pericardial cavity is between them

Question 22

What is the visceral layer of the pericardium also called?

Answer 22

Epicardium (outer layer of the myocardium)

Question 23

1) What is the pericardial cavity?
2) What is the transverse pericardial sinus?
3) What is the other pericardial sinus?

Answer 23

1) Potential space with thin film of serous fluid
2) Reflection of pericardium
3) Oblique pericardial sinus

Question 24

What structure of the heart is similar to the pleura of the lungs?

Answer 24

The pericardium

Question 25

What would fluid in the pericardial cavity cause?

Answer 25

The heart wouldn’t be able to move to fully fill; CO would drop and so would venous return

Question 26

Why does cardiac tamponade (fluid in pericardium) affect diastole?

Answer 26

Fibrous pericardium doesn’t stretch

Question 27

What are the 3 layers of the pericardium?

Answer 27

1) Fibrous (gray)
2) Parietal serous
3) Visceral serous (aka epicardium)

Question 28

What is the epicardium also called?

Answer 28

Visceral pericardium