How do the atria and ventricles differ in feeling or touch?

Question

the reason is because we are dissecting pigs and i forgot to check. This is a question in my study guide.

Answer 1

We-elll...it's all muscle.  The ventricles have thicker walls, but truthfully unless the organ was dissected and I was feeling the thickness of the walls I don't think I could tell just from touching which was which.  You might be able to tell on the insides from touch because the ventricles have the chordae tendinae in them ( the tendons connecting to the tricuspid and  mitral valves) and the trabeculae carnae (ridges of muscle projecting from the inner surface of the ventricles), but again, that would necessitate dissection.

From the outside, it's pretty much all white meat.

Answer 2

Marie made many good points, but I have a few more to add.

Both the left and right atria have thin walls, and the blood inside is quite low in pressure (0-10 mmHg), so you can easily indent the walls with your finger -- in fact, people doing internal cardiac massages can rip the heart open if they are not careful.

Anyway, you may also be able to feel the atrial appendages -- depending on how much pericardial fat there is.

The right ventricle is more muscular than the atria, but still relatively low-pressured (about 30 mmHg in systole), so it feels quite firm, but not rock-hard.  If you have a blood pressure cuff, inflate it a bit, and push while watching the gauge, and you'll know what 30 mmHg feels like.

The left ventricle, as you know, is the most muscular of the four chambers, and because it's highly pressurized in systole (120 mmHg) it feels like Arnold's biceps....

Just out of curiosity, why do you ask this question?