Heart and Mediastinum

Question 1

What are the three layers of the pericardium sac?

Answer 1

1. Fibrous pericardium (most external)
2. Parietal layer of serous pericardium
3. Visceral layer of serous pericardium (most internal)

Question 2

What are the innervations of the pericardium (somatic and autonomic)?

Answer 2

• Somatic: Phrenic nn. (C3-5)

- Autonomic: Vagus nn. (parasympathetics) and Cardiopulmonary splanchnic nn. (sympathetics)

Question 3

What are the blood supplies of the pericardium?

Answer 3

Pericardiacophrenic aa. and vv.

Question 4

Describe the flow of blood through the heart.

Answer 4

Deoxygenated: comes into heart from SVC/IVC to right atrium then through the tricuspid valve to the right ventricle then through the pulmonary valve and into the lungs via the pulmonary trunk and two pulmonary arteries
- IN LUNGS -
Oxygenated: comes into heart from lungs via pulmonary veins to the left atrium then through the bicuspid valve into the left ventricle then through the aortic valve into the aorta and to the rest of the body

Question 5

What is happening in the ventricles during diastole and systole?

Answer 5

• Diastole: ventricles filling (AV valves open)

- Systole: ventricle emptying (AV valves closed, pulmonary and artery valves open)

Question 6

Describe the path taken for referred cardiac pain.

Answer 6

Pain follows sympathetic pathway then travels to the posterior horns of T1-4
- Pain is sometimes felt in the entire chest and down the medial arms

Question 7

What are the three branches that come off the aortic arch?

Answer 7

• Brachiocephalic trunk (right common carotid and right subclavian come off here)
• Left common carotid a.
• Left subclavian a.

Question 8

What are the branches of the descending thoracic aorta and how many are there of each?

Answer 8

• Bronchial aa. (1 pair)
• Esophageal (3-5)
• Posterior intercostal aa. (9 pairs)
• Subcostal aa. (1 pair)

Question 9

Do the Azygos system veins have valves?

Answer 9

NO

Question 10

At what vertebral levels do the Accessory hemiazygos v. and Hemiazygos v. branch from the Azygos v.?

Answer 10

• Accessory hemiazygos v.: T8

- Hemiazygos v.: T9

Question 11

Where does the thoracic duct drain into?

Answer 11

Thoracic duct drains into the left venous angle

Question 12

Where does the right lymphatic duct drain into?

Answer 12

Right lymphatic duct drains into the right venous angle

Question 13

What veins make up each of the venous angles?

Answer 13

• Left venous angle: left subclavian v. and left internal jugular v.
• Right venous angle: right subclavian v. and right internal jugular v.

Question 14

What are the three plexuses that the Vagus nn. are involved in?

Answer 14

• Cardiac plexus
• Pulmonary plexus
• Esophageal plexus