Pericardium and Heart Nervous Innervation

Question 1

Label the pericardium layers:

Answer 1

Question 2

The external heart and the roots of the great vessels are immediately covered with:

Answer 2

visceral pericardium of the epicardium

Question 3

Formation of the pericardial cavity:

Answer 3

1. visceral pericardium covers heart and great vessels.
2. visceral pericardium reflects off great vessels to become parietal pericardium on both sides.
3. pericardial cavity in between visceral and parietal pericardium.

Question 4

The parietal layer of epicardium is fused to the inner surface of:

Answer 4

the fibrous pericardium

Question 5

The fibrous pericardium is continuous with:

Answer 5

• adventitial layer of great vessels.
• superior fascia of diaphragm.

NOT ELASTIC; LEADS TO CARDIAC TAMPONADE

Question 6

Cardiac tamponade:

Answer 6

• A rapid accumulation of fluid in the pericardial cavity will not expand outward due to the fibrous pericardium.
• Heart will become compressed, negatively affecting diastole. Cardiac output will be reduced.

Question 7

The two pericardial sinuses formed by the epicardium reflections:

Answer 7

1. transverse sinus
2. oblique sinus

Question 8

Transverse sinus openings and boundaries:

Answer 8

• open at both ends.
• Anterior: bounded by ascending aorta and pulmonary trunk
• Posterior: bounded by SVC

Question 9

Oblique sinus openings and boundaries:

Answer 9

• blind recess: closed superiorly and laterally but open inferiorly.
• Bounded by IVC and the four pulmonary veins (all “inflow vessels”).

Question 10

Cell type of cardiac conduction system:

Answer 10

modified cardiac muscle cells (Purkinje fibers)

Question 11

Pacemaker cells’ function and location:

Answer 11

• fastest depolarizing cells in the heart.
• set heart rate.
• located in sinoatrial node.

Question 12

Location and content of sinoatrial node:

Answer 12

• subepicardium of right atrium near entrance of SVC.
• Contains pacemaker cells.

Question 13

What separates the atrial conductive system from the ventricular conducting system?

Answer 13

cardiac fibrous skeleton.

Question 14

What connects the atrial conductive system to the ventricular conducting system?

Answer 14

atrioventricular (AV) bundle

Question 15

Location and function of atrioventricular node:

Answer 15

• Location: subendocardium of right side of interatrial septum.
• Function: Retards wave of depolarization as it passes through node to the atrioventricular bundle into the ventricles.

Question 16

Location and function of atrioventricular bundle:

Answer 16

• Location: leave AV node and pass through cardiac fibrous skeleton to reach the interventricular septum.
• Function: connects atrial and ventricular conductive systems.

Question 17

Path of heart conduction:

Answer 17

1. pacemaker cells in sinoatrial nodes depolarize. Atria contract.
2. depolarization retarded by AV node.
3. depolarization travels through AV bundle past fibrous cardiac skeleton into interventricular septum.
4. AV bundle divides into right and left bundle branches.
5. Right bundle branch gives off moderator band to anterior papillary muscles.
6. Ventricles contract.

Question 18

The right and left atrioventricular bundle branches travel in:

Answer 18

• interventricular septum
• right bundle branch gives off moderator band

Question 19

Label all:

Answer 19

Question 20

Role of sympathetic and parasympathetic innervation to the heart:

Answer 20

• modulates cardiac cycle (via SA node) and force of contraction.

Question 21

Heart sympathetics.

Preganglionic and postganglionic cell body locations:

Answer 21

• Preganglionic: upper thoracic spinal cord (T1-T4).
• Postganglionic: cervical and upper thoracic sympathetic ganglia.

Question 22

Heart parasympathetics.

Preganglionic and postganglionic cell body locations:

Answer 22

• Preganglionic: brain stem. Travel on vagus nerve.
• Postganglionic: cardiac plexus (wall of heart).

Question 23

Path nerve fibers that monitor cardiac reflexes and do not reach conscious levels:

Answer 23

• course with vagus nerve and enter the CNS at medulla.

Question 24

Path of sensory nerve fibers that monitor heart ischemia and reach conscious levels:

Answer 24

• run with sympathetics to dorsal root ganglia in T1-T4.
• pain felt in T1-T4 dermatomes.

Question 25

Heart ischemia will lead to what kind of pain?

Answer 25

• pain/discomfort (angina) in T1-T4 dermatomes.
• upper chest and medial arm.