Cardiac cycle

The heart is the organ that helps supply blood and oxygen to all parts of the body. It is divided by a partition (or septum) into two halves. The halves are, in turn, divided into four chambers. The heart is situated within the chest cavity and surrounded by a fluid-filled sac called the pericardium. This amazing muscle produces electrical impulses that cause the heart to contract, pumping blood throughout the body. The heart and the circulatory system together form the cardiovascular system. Heart Anatomy The heart is made up of four chambers: • Atria: Upper two chambers of the heart. • Ventricles: Lower two chambers of the heart. Heart Wall The • Epicardium: The outer layer of the wall of the heart. • Myocardium: The muscular middle layer of the wall of the heart. • Endocardium: The inner layer of the heart. Cardiac Conduction Cardiac conduction is the rate at which the heart conducts electrical impulses. Heart nodes and nerve fibers play an important role in causing the heart to contract. • Atrioventricular Bundle: A bundle of fibers that carry cardiac impulses. • Atrioventricular Node: A section of nodal tissue that delays and relays cardiac impulses. • Purkinje Fibers: Fiber branches that extend from the atrioventricular bundle. • Sinoatrial Node: A section of nodal tissue that sets the rate of contraction for the heart. Cardiac Cycle The • Diastole phase: The heart ventricles are relaxed and the heart fills with blood. • Systole phase: The ventricles contract and pum...

Cardiac Cycle:The heart’s primary function is to circulate blood throughout the body in a cycle. Every day, the human heart beats around 100,000 times. The cardiovascular system involves systemic and pulmonary circulation and is responsible for the transport of various substances in human beings, and is composed of the heart, arteries, veins, and blood capillaries. The heart’s valves control blood flow, resulting in structured blood propulsion to the next chamber. The cardiac cycle is a series of heart contractions that pressurise distinct chambers of the heart, forcing blood to flow in one direction. Read on more about the cardiac cycle, meaning, duration, and phases for better understanding. Cardiac Cycle: Meaning The cardiac cycle events are the sequence of events that occur during a heartbeat. The (Sinoatrial) SA node possesses the properties of automaticity and rhythmicity. As a result, it causes action potentials that spread throughout the atrial and ventricular muscle fibres. As a result, depolarization and repolarization occur. Following that, the heart undergoes several changes, which are repeated from beat to beat. The cardiac muscle cells, or cardiomyocytes, that make up the heart muscle are responsible for pumping the blood. Cardiomyocytes, which are separate muscle cells that are striated like skeletal muscle yet pump rhythmically and involuntarily like a smooth muscle. The heart contracts (systole) during each cardiac cycle, pushing blood out and pumping it a...

The electrical system of the heart is critical to how it The movement of electrical signals across the heart is what is traced on an electrocardiogram (EKG). The EKG is also what allows irregularities in the heart's electrical system, and with them any related symptoms and medical conditions, to be assessed. This article explains five components of the cardiac conduction system and how they work. It also discusses how Where Do Electrical Impulses Start in the Heart? The heart generates its own electrical signal. This electrical signal is produced by a tiny structure known as the sinus node, located in the upper portion of the right atrium. The right atrium is one of four The cardiac electrical signal controls the heartbeat in two ways. First, since each electrical impulse generates one heartbeat, the number of electrical impulses determines the heart rate. In a normal sinus rhythm, that rate will be between 60 and 100 beats per minute. The sinus node signal also controls electrical conduction as it "spreads" across the heart. It causes the cells of the Illustration by Mira Norian for Verywell Health The components of the heart's electrical system, including the sinus node (SN) and atrioventricular node (AV node), are illustrated here. You can see the two atria and the two ventricles. Separating them is a layer of fibrous tissue, labeled the AV disc. This tissue keeps the electrical signal passing through the AV node. In this figure: • SN = sinus node • AVN = AV node • RA =...