Innervation of the heart wall

Question 1

Control of inherent rate of contraction of heart

Answer 1

Pacemaker cells of SA node

Question 2

Control of change of HR

Answer 2

Autonomic nervous system

Question 3

Fibrous and parietal (serous) pericardium innervation

Answer 3

Phrenic nerve

- Carries pain sensation

Question 4

Visceral (serous) pericardium and heart wall parasympathetic innervation

Answer 4

Vagus nerve

Question 5

Visceral (serous) pericardium and heart wall sympathetic innervation

Answer 5

Cervical and upper thoracic ganglia T1-4

- Carries sensory and pain fibres

Question 6

Autonomic motor fibres route to heart

Answer 6

Via cardiac/cardiopulmonary plexus situated at the bifurcation of the trachea

Question 7

Sympathetic (T1-4) target cells (3)

Answer 7

• SA node
• AV node
• Myocytes (contractility)

Question 8

Parasympathetic (CN X) target cells (2)

Answer 8

• SA node

- AV node

Question 9

SA node location

Answer 9

Lies near opening of the SVC in the right atrium

Question 10

AV node location

Answer 10

Lies in the inferior part of the interatrial septum

Question 11

Atrioventricular bundle (of His) location

Answer 11

Lies within each side of the interventricular septum

Question 12

Pain associated with cardiac ischaemia

Answer 12

• Carried back via afferent fibres of sympathetic nerves to T1-4 vertebral levels
• ‘Constricting’ pain is experienced in on the anterior chest wall and on medial side of left arm (related to dermatomal distribution)