Introduction

The frog heart preparation allows a number of important properties of cardiac muscle to be investigated relatively easily. Contractions of the denervated heart can be recorded and the effect of chemicals such as adrenaline and acetylcholine, which mimic the effects of stimulating autonomic nerves, can be measured. Electrical conduction can be studied using Stannius ligatures and properties such as the refractory period can be investigated by stimulating the heart electrically while it is contracting.