5. The Heart

Question 1

What are the 4 layers of heart tissue?

Answer 1

Pericardium, Epicardium, Myocardium, Endocardium

Question 2

What are the 2 layers of pericardium?

Answer 2

Parietal = Fibrous outer sac
Visceral = Thick as coronary vessels to reduce friction

Question 3

Describe Pericardium

Answer 3

Flattened layer of simple squamous resting on a thin layer of fibrous connective tissue.

Question 4

What is the epicardium?

Answer 4

Underlying adipose connective tissue, blood vessels and nerves.

Question 5

What is the Myocardium?

Answer 5

Cardiac myocytes joined by intercalated discs

Question 6

How are Atrial myocytes different?

Answer 6

Smaller due to lower pressure and secrete ANP to lower blood pressure (endocrine)

Question 7

Describe Perkinje fibres

Answer 7

Modified muscles cells with a large vacuole storing glycogen that appears magenta with PAS.

Question 8

Describe Endocardium

Answer 8

Thin layer of fibrous connective tissue lying on simple squamous epithelium

Question 9

SAN and AVN cells

Answer 9

Small, irregular myocytes adapted for impulse conduction with many blood and nerves.

Question 10

Describe valves

Answer 10

Thick collagen fibres, occasional elastic covered by endothelial cells.

Question 11

What accumulates in cardiac myocytes with age?

Answer 11

Perioxidation of lipids form yellow/brown lipofuscin pigment

Question 12

What are Weibel-Palade bodies?

Answer 12

Endothelial cells in the heart control how blood clots form