Heart & Pericardial Sac - Ach

Question 1

What are the four subdivisions of the mediastinum? What is in each division?

Answer 1

• Middle:
  
  • pericardium, heart, roots of the great vessels
• Superior: (above T4-T5/sternal angle plane)
  
  • great veins, aorta & branches, parts of trachea, esophagus, vagus nerve, recurrent laryngeal nerves, thoracic duct, thymus
• Anterior:
  
  • anterior to fibrous pericardium, but posterior to sternum
  • thymus
• Posterior:
  
  • esophagus, descending aorta, thoracic duct

Question 2

What are the two layers of the pericardium?

Answer 2

• FIBROUS
  
  • outer pericardium, fatty and blends with central tendon of diaphragm
• SERIOUS
  
  • inner pericardium, two layers lubricated by serous fluid

Question 3

What is the innervation and blood supply to the Fibrous Pericardium?

Answer 3

• innervated by Phrenic Nerves
• supplied by Pericardiacophrenic Arteries

Question 4

What are the two layers of the Serous Pericardium?

Answer 4

• Parietal Pericardium
  
  • backside of Fibrous pericardium
• Visceral Pericardium
  
  • on heart, AKA Epicardium

Question 5

What is the innervation and blood supply to the Serous Pericardium?

Answer 5

• innervated by Coronary Plexus
• supplied by Coronary Arteries

Question 6

Reflections of the visceral pericardium onto the great vessels form what two sinuses?

Answer 6

• Transverse Pericardial Sinus
  
  • used in cardiac surgery to clamp aorta and pulmonary trunk
• Oblique Pericardial Sinus
  
  • cul-de-sac bordere by pulmonary veins and IVC

Question 7

Where and why is pericardial pain referred?

Answer 7

• Where?
  
  • skin of the ipsilateral supraclavicular region (top of the shoulder of the same side)
    
    • C3-C5 dermatomes
• Why?
  
  • pain impulses conducted from the pericardium by the somatic phrenic nerves result in referred pain sensations

Question 8

What vein leads into the Coronary Sinus and is the greatest tributary of the Coronary Sinus?

Answer 8

Great Cardiac Vein

Question 9

Where do the Small and Middle Cardiac Veins drain into the Coronary Sinus?

Answer 9

Right before the Coronary Sinus drains into the Right Atrium.

Question 10

What blood vessels descends in the Anterior Interventricular Sulcus?

Answer 10

LAD

Question 11

Where do 40-50% of Coronary occlusions occur?

Answer 11

Anterior IV artery (LAD)

Question 12

The SA node is supplied by what blood vessel in 60% of people?

Answer 12

Right Coronary Artery

Question 13

What blood vessel descends in the Posterior Interventricular Sulcus?

Answer 13

Posterior Interventricular Artery

(off of the RCA)

Question 14

Where does the Sympathetic nerve supply to the heart come from?

Answer 14

• Postganglionic fibers from the Cervical Ganglia and Upper Thoracic Ganglia
  
  • terminate in the SA and AV nodes
    
    • increase rate
    • increase force of contraction
    • dilate coronary arteries

Question 15

Where does the Parasympathetic nerve supply to the heart come from?

Answer 15

• Preganglionic fibers of the Vagus Nerve (CN X)
  
  • pass through Cardiac Plexus
  • synapse onto postganglionic neurons in ganglia in the walls of the atria
    
    • decrease rate
    • decrease force of contraction
    • constrict coronary arteries