Best Answer: The definitions will tell you the differences. The nucleus, in a eukaryotic cell, contains the DNA for cell function and, therefore, is the control center of the cell (It is NOT a brain).It also contains the nucleolus which is the site where ribosomes are manufactured.he nucleus, in a eukaryotic cell, contains the DNA for cell function and, therefore, is the control center of the cell (It is NOT a brain). It also contains the nucleolus which is the site where ribosomes are manufactured.
The heart contains four chambers. The two upper chambers are the atria and the two lower chambers are the ventricles. On the cranial surface of each atrium is a pouch-like appendage called an auricle which is thought to increase the capacity of the atrium slightly.
The heart is the hollow, muscular organ in the thoracic cavity (chest) that maintains the circulation of blood throughout the body. It is surrounded by a membrane called the pericardium.lood passes from the left atrium through the mitral valve and into the left ventricle. The left ventricle, the largest and most muscular of the four chambers, is the main pumping chamber of the heart.