Frog Heart DEMO

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 (epinephrine) 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.

Aims

To better understand the important properties of heart muscle.

This will be achieved by studying the results of a number of simple experiments on the denervated frog heart:

• Autonomic nervous control of the heart - effect of adrenaline (sympathomimetic) and acetylcholine (parasympathomimetic).
• Adaptation of the amphibian heart to changes in environmental temperature.
• The electrical properties of cardiac muscle - the refractory period.
• The electrical conducting pathway in the frog heart - experiments with Stannius ligatures.