Lesson 3: The Cardiac Cycle Flashcards
what is a heartbeat also known as
a cardiac cycle
explain the first phase of the cardiac cycle
the atrioventricular valves open and the atria contract at the same time, moving the blood into the ventricles. the atrioventricular valves then close and the atria rests
explain the second phase of the cardiac cycle
the semilunar valves open and the ventricles contract at the same time, moving the blood into the arteries. the semilunar valves close and the ventricles rest
what is the last phase of the cardiac cycle
the heart relaxes before starting the process again
what is it called when a portion of the heart is active
it is in systole
what is it called when a portion of the heart is inactive
it is in diastole
what is the contraction of the heart controlled by
specialized cardio-nervous tissue found in the RIGHT atrium
what are the two types of nodal tissue
sinoatrial node(SA node) and the atrioventricular node(AV node)
what is the function of the nodal tissue
to send and receive electrical signals that initiate and regulate heart contraction
where is the SA node found
in the upper dorsal(back) region of the right atrium
where is the AV node found
the lower portion of the right atrium
where are the nodal tissues located
in the right atrium
what is the specific function of the SA node
it sends out an impulse every 0.85 seconds causing the atria to contract. it keeps the heartbeat regular
what is the specific function of the AV node
receives the signal from the SA node and sends its own signal to the Purkinje fibres that cause the ventricles to contract
would the heart continue to beat without the SA node
yes
