Ventricular Contraction Essay

The focus of the investigation explored the fundamental properties of cardiac muscle on a cane toad’s (Bufo marinus) heart and the adaptive ability of the heart to produce a response when subject to different conditions of temperature, stretch on contractile force, substances of acetylcholine, adrenaline and atropine, and increased frequency of stimulus. Regarding Figure 1, the regular heartbeat and contraction force of the toad was identified to demonstrate the difference between atrial contractions and ventricular contractions in a normal environment. In cardiac, skeletal, and some smooth muscle tissue, contraction occurs through a spectacle known as excitation contraction coupling (Freeman et al., 2014). This process converts electrical stimulus from the neurons into a mechanical response, to facilitate muscle movement (McCorry, 2007). The spontaneous, rhythmic generation of action potentials in the intrinsic pacemaker centres of the heart is the basis of the autonomous heartbeat rhythm (Sarnoff et al., 1960).
The application of warm Ringer solution on the heart remained unchanged and consistent in each contraction
The direct application of acetylcholine on the heart decreases the heart rate and the force of contraction (Figure 5). This change in heart rate is described by the membrane becoming hyperpolarised and the decrease in prepotentials due to the action of acetylcholine on muscarinic receptors and potassium channels (Pal and Pal, 2006). Acetylcholine produces parasympathetic effects by binding to muscarinic cholinergic receptors, which activate G-proteins and opens potassium channels known as hyperpolarisation, while closing sodium and calcium channels (Pal and Pal, 2006). The action of acetylcholine in inhibiting impulse formation, conduction and in weakening auricular contraction, exhibits a stimulating effect, particularly on the ventricle (McDowall,