The Pericardium & Heart Wall

Question 1

Layers of the pericardium

Answer 1

1. FIBROUS LAYER
2. PARIETAL: outer serous
3. PERICARDIAL CAVITY: thin serous fluid
4. VISCERAL EPICARDIUM: simple squamous epith., basement, coronary arteries
5. MYOCARDIUM: arterial wall, smc + elastic, intercalated disc, gap junctions
6. ENDOCARDIUM: simple squ. epithelium, basement membrane => gives rise to valves

Question 2

Role of fibrous pericardium

Answer 2

protect from sudden changes of overfilling

Question 3

Pericardium innervatiion

Answer 3

FIBROUS + PARIETAL: Phrenic nerve (lateral), PAIN (motorsensory)

VISCERAL: T1-T4 nerves, Vagal (via cardiac plexus) (symp.)

Question 4

Arterial Blood Supply of Pericardium

Answer 4

FIBROUS + PARIETAL: pericardiacophrenic artery, internal thoracic artery (branch subclavian artery)

VISCERAL EPI: coronary arteries

Question 5

Attachments of pericardium

Answer 5

*base lays over the diaphragm and is attached to the central tendon of the diaphragm by the pericardiacophrenic ligament

*

Question 6

Functions of the Pericardium

Answer 6

• Fixes heart
• Prevents overfilling
• Lubrication
• Protects inner heart from infection (d/t fibrous layer)

Question 7

COMPONENTS OF HEART WALL

Answer 7

1. EPICARDIUM simple squamous lining, connective tissue and fat. SECRTION of lubricating fluid into the pericardial cavity.
2. MYOCARDIUM:
3. SUBENDOCARDIUM: loose fibrous tissue, containing the vessels and nerves of conducting system ; The purkinje fibres
4. ENDOCARDIUM: lining, valves; simple squamous

Question 8

Heart Wall Extrinsic Innervation

Answer 8

1. Autonomic vagus nerve (parasymp) = HR and T1-4 (sympathetic) = contraction routed via CARDIOPULMONARY NERVE PLEXUS via CARINA
2. T1-T4 sympathetic pain and sensory

Question 9

Basis of referred pain

Answer 9

T1-T4 also supply the dermatomes of inner aspect of left upper arm + impulses are stronger than autonomic therefore pain from heart interpreted as coming from source.