Explain Why The SA (SA Node) Is In The Right Atrium Of The Heart

The SA (sinoatrial node) is a pacemaker that is in the right atrium of the heart. SA node control the heart rate using the electrical impulses that sends to the heart muscles and this is how the heart pumping blood out to the entire body and how the heart contract. The stages of the pathway of action potential: 1) The Action Potential is in the Sinoatrial node (SA). Action potential then travels from the SA node to the AV (atrioventricular node) by crossing to the wall of the atrium. 2) Then the action potentials slowly pass through the AV node and it give time for the atria to contract. 3) Then it’s rapidly passes through the atrioventricular bundle that extends to the AV node to the fibrous skeleton and into the interventricular septum. 4)
5) The Purkinje fibers carried the action from the bundle branches to the ventricular walls. 6) The ends of the Purkinje fibers allow the ventricular muscles cells to contract because the action potential is rapidly passes through the AV bundle to the end of the Purkinje and this cause a rapid conduction and its providing a very strong contraction to the ventricular muscle. The intercalated discs are a network that allows the rapid transmission of the electrical impulses and this allows the action potentials to travel to one cardiac muscle cells to the next. Sympathetic Nervous System carry the nerve impulses from the brain (medulla oblongata) to the heart and it releases hormones (that increases the heart rate). Parasympathetic Nervous System also releases hormones that slow down the heart rate. The hormone is called acetylcholine. The neurotransmitters are involved in sympathetic nervous system are: acetylcholine (sympathetic ganglion) and norepinephrine (post-ganglionic) and for the parasympathetic nervous system are: acetylcholine (preganglionic) and norepinephrine (noradrenaline) or epinephrine