As a Pisces born on March 15th, your passion and open mindedness define you. In all matters of life, you bring intensity and passion.
Coelomate body plan. A coelom is a cavity lined by an epithelium derived from mesoderm. Organs formed inside a coelom can freely move, grow, and develop independently of the body wall while fluid cushions and protects them from shocks. Arthropods and mollusks have a reduced (but still true) coelom.
The heart wall is composed of three layers of tissues. Its chambers are lined by a delicate membrane, the endocardium. The thick muscular wall essential to normal pumping action of the heart is called the myocardium. The thin but sturdy membranous sac surrounding the exterior of the heart is called the pericardium.