Electrical activity of the heart Flashcards
what is the electrocardiogram?
it is a record or display of a person’s heartbeat produced by electrocardiography
what does ECG stand for?
electrocardiogram
what is an electrocardiogram used for?
it is a non invasive routine examination of the electrical activity of the heart used to reflect underlying heart conditions
what do the impulses show on an ECG?
the impulses can show signs of structural or metabolic changes like enlargement or hypoxia of cardiac muscle
where do electrical signals in the heart start from?
they start in a group of cells at the top of your heart called the sinoatrial node
where does the electrical signal in the sinoatrial node then travel to?
the electrical signal then travels down through your heart, triggering first your 2 atria and then your 2 ventricles
what happens after the 2 atria and 2 ventricles of the heart have been triggered from the electrical signal which originated in the sinoatrial node?
the lower heat chambers contract or pump
as the sinoatrial node fires electrical impulses, where do these electrical impulses travel to?
the electrical impulses travel through the left and right atrium
what does the electrical activity in the heart cause?
the electrical activity causes the 2 upper chambers of the heart to contract
how can the electrical activity of the heart be recorded?
it can be recorded from the surface of the body as a P wave on the patients ECG
what excitation-contraction coupling in cardiac muscle?
it is the process whereby an action potential triggers myocytes to contract, followed by subsequent relaxation
where is the primary pacemaker site within the heart?
the cells within the sinoatrial node
what are examples of non-pacemaker action potentials in the heart?
arterial myocytes
ventricular myocytes
purkinje cells
describe the membrane potential of non-pacemaker cells
non-pacemaker cells in the heart have a true resting membrane potential that remains near the equilibrium potential for potassium ions
what sends out an electrical impulse in the heart?
the sinoatrial node
