Histology

Question 1

Describe the fibrous skeleton of the heart

Answer 1

four fibrous rings surround the valves, made of dense irregular connective tissue. These rings provide attachment points for all four valves. The membranous portion of the interventricular septum is devoid of cardiac muscle, instead it is dense connective tissue which contains a portion of the conducting system of the heart. The entire skeleton is an insulator which allows for proper channeling of electrical impulses across the heart.

Question 2

Describe the coronarly vasculature

Answer 2

Two coronary arteries and cardiac veins. Right and left coronary arteirs arise from the ascending aorta and circle the base of the heart. The cardiac veins drain to the coronar sinus on the posterior suface and then into the right atrium.

Question 3

3 Layers of the heart.

Answer 3

Epi, myo and endocardium.

The epicardium give rise to visceral and parietal layers of the pericardium.

Question 4

Layers within the heart valves

Answer 4

Spongiosa

Fibrosa

Ventricularis

Question 5

Histologic characteristics of the conducting sytem

Answer 5

Nodal cells are modified muscle fibers that are smaller than surrounding cardiac muscle cells.

Whereas Purkinje fibers are larger than surrounding ventricular muscle cells.

Question 6

What are these?

Answer 6

Endothelial cells of the Aorta

Question 7

What are these?

Answer 7

More endothelial cells of the aorta. Note those that are attached vs those that are seperated.

What would they look like en-face?

Question 8

What are these?

Answer 8

1. Tunica Adventitia
2. Tunica Media
3. Tunica Intima

Question 9

What is this?

Answer 9

Cross section of the heart wall showing

Epicardium containing vasculature and adipose tissue

Myocardium

and a vauge circle around endocardium

Note the vassels in the epicardium, which may be the coronary arteries and sinus.