Heart Histology

Question 1

What are the three vessel tunics of blood vessels?

Answer 1

1. tunica intima
2. tunica media
3. tunica adventitia

Question 2

Tunuca intima is analogous to what part of the heart? What type of tissue is it?

Answer 2

endocardium

made of simple squamous epithelial lining (endothelium)

also includes the subendothelial connective tissue layer

Question 3

The tunica media is analogous to what part of the heart? COmpsoed of what type of tissue?

Answer 3

myocardium

it’s composed primarily of smooth muscle cells arranged concentrically around the lumen

Question 4

THe tunica adventitia is analogous to what part of the heart? Composed of what tissue?

Answer 4

epidardium

composed of fibroelastic connective tissue arranged longitudinally

Question 5

What are the three layers of the heart?

Answer 5

endocardium on the inside, myocardium in the middle, epicardium on the outside

Question 6

What are the layers of the endocardium inner lining of the heart?

Answer 6

1. endothelium - simple squamous
2. thing subendothelial layer (find collagenous and elastic fibers)
3. layer of denser CT with elastic fibers
4. Subendocardial layer - loose CT with small blood vessels, nerves and purkinje fibers

Question 7

The myocardium is composed of cardiac myocytes connected into contractile sheets by what?

Answer 7

intercalated discs

Question 8

Why is the spiral arrangement of the muscle fibers around the chambers of the heart significant?

Answer 8

means blood is “wrung” out of the ventricles during contraction

Question 9

Besides the cardiac myocytes, what else helps comprise the myocardium?

Answer 9

the endomysium - fine CT found between adjacent cells

specialized cardiac muscle cells - attached to fibrous skeleton, specialized for endocrine secretion, specialized for impulse generation/conduction, etc.

Question 10

Wha are the two layers of epicardium?

Answer 10

inner fibrous layer and outer serous layer (visceral layer of the pericardium)

Question 11

What does the inner fibrous layer contain?

Answer 11

loose CT
numerous fat cells
bundles of nerve fibers
arteries and veins - coronary vessels

Question 12

What tissue is the outer serous layer of the epicardium made from?

Answer 12

simple squamous epithelium

Question 13

Where ist he SA node?

Answer 13

wall of the superior vena cava adjacent to its junction with the right atrium

Question 14

Where is the AV node?

Answer 14

lies in the interatrial septum near the opening of the coronary sinus

Question 15

In what layer of the heart are purkinje fibers found?

Answer 15

in the deepest layer of the endocardium

Question 16

Depolarization of the purkinje fibers leads to contraction of what?

Answer 16

the ventricular walls (starting at the apex) and the papillary muscles

Question 17

What is the cardiac skeleton made of?

Answer 17

tough, dense connective tissue

Question 18

What structure is the cardiac skeleton in general?

Answer 18

four valve rings joined together - atria and arterial trunks attach to the superior surface and ventricles and AV valve leaflets fasten to the inferior aspect.

Question 19

Valves are formed by what layer of the heart/

Answer 19

endocardium (covered by endothelium)

Question 20

What is at the core of the valves?

Answer 20

dense fibro-elastic connective tissue