what is nodal tissue ?Are they present only in heart?

Nodal tissue is a special type of tissue which can act both as muscle tissues and nerve tissue. This tissue can contract like muscles and also generates impulses like nerves.

Yes, nodal tissues are only present in heart which when contract, generate nerve impulses throughout the heart. Heart has two types of nodes made up of nodal tissues – Sinoatrial node (pacemaker) and Atrioventricular node (AV node).