Heart's Electrical System and Blood Flow
Think of your heart as having its own built-in electrical circuit that keeps everything running smoothly. The cardiac conduction system is like the heart's personal electrician - it sends electrical signals that make your heart contract in exactly the right order.
Your heart is myogenic, which means it generates its own electrical impulses without needing signals from your brain. Pretty cool, right? It all starts with the SA node (sinoatrial node), which is basically your heart's natural pacemaker located in the right atrium.
Here's how the electrical wave travels: The SA node fires an electrical impulse that spreads through the atria walls, making them contract and push blood into the ventricles. Then the signal hits the AV node (atrioventricular node), which acts like a traffic light - it delays the signal for about 0.1 seconds to make sure the atria finish contracting before the ventricles start.
Quick Tip: Think of it like a Mexican wave - the electrical impulse spreads through your heart muscle in a coordinated wave pattern!
The signal then travels down the bundle of His and splits into bundle branches before spreading through Purkinje fibres in the ventricle walls. This makes the ventricles contract and pump blood out of your heart. Meanwhile, your blood vessels have specific jobs: the aorta carries oxygenated blood from your heart to your body, whilst the vena cava brings deoxygenated blood back to your heart.
