LIST THE ELEMENTS OF THE INTRINSIC CONDUCTION SYSTEM IN ORDER, STARTING FROM THE SA NODE.

SA NODE -> ATRIOVENTRICULAR (AV) NODE -> ATRIOVENTRICULAR (AV) BUNDLE -> BUNDLE BRANCHES -> PURKINJE FIBERS

AT WHAT STRUCTURE IN THE TRANSMISSION SEQUENCE IS THE IMPULSE TEMPORARILY DELAYED? WHY?

ATRIOVENTRICULAR (AV) NODE; THIS DELAY IS IMPORTANT BECAUSE IT ENSURES THAT THE ATRIA HAVE EJECTED THEIR BLOOD INTO THE VENTRICLES FIRST BEFORE THE VENTRICLES CONTRACT.

EVEN THOUGH CARDIAC MUSCLE HAS AN INHERENT ABILITY TO BEAT, THE NODAL SYSTEM PLAYS A CRITICAL ROLE IN HEART PHYSIOLOGY. WHAT IS THAT ROLE?

GENERATE ACTION POTENTIALS AT A GREATER FREQUENCY THAN OTHER CARDIAC MUSCLE CELLS, THEY ARE THE PACEMAKER OF THE HEART. THEREFORE, IT SETS THE HEARTRATE UNDER NORMAL CIRCUMSTANCES

DEFINE ECG

THE GRAPHIC RECORDING OF THE ELECTRICAL CHANGES (DEPOLARIZATION FOLLOWED BY REPOLARIZATION) OCCURING DURING THE CARDIAC CYCLE.

DRAW AN ECG WAVE FORM REPRESENTING ONE HEARTBEAT. LABEL THE P, QRS, AND T WAVES; THE P-R INTERVAL; THE S-T SEGMENT, AND THE Q-T INTERVAL.

WHY DOES HEART RATE INCREASE DURING RUNNING?

IN GREATER DEMAND WHEN OUR BODY IS UNDER THAT KIND OF STRAIN. THE HEART MUST BEAT FASTER AND HARDER IN ORDER TO DELIVER THE LARGER AMOUNT OF BLOOD TO MUSCLES BEING USED WHEN RUNNING.

DESCRIBE WHAT HAPPENS IN THE CARDIAC CYCLE IN THE FOLLOWING SITUATIONS.

IMMEDIATELY BEFORE THE P WAVE

HEART IS IN DIASTOLE

DESCRIBE WHAT HAPPENS IN THE CARDIAC CYCLE IN THE FOLLOWING SITUATIONS.

DURING THE P WAVE

DEPOLARIZATION OF ATRIA

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DESCRIBE WHAT HAPPENS IN THE CARDIAC CYCLE IN THE FOLLOWING SITUATIONS.

IMMEDIATELY AFTER THE P WAVE (P-R SEGMENT)

CONTRACTION OF ATRIA

DESCRIBE WHAT HAPPENS IN THE CARDIAC CYCLE IN THE FOLLOWING SITUATIONS.

DURING THE QRS WAVE

DEPOLARIZATION OF VENTRICLES

DESCRIBE WHAT HAPPENS IN THE CARDIAC CYCLE IN THE FOLLOWING SITUATIONS.

IMMEDIATELY AFTER THE QRS WAVE (S-T INTERVAL)

CONTRACTION OF VENTRICLES

DESCRIBE WHAT HAPPENS IN THE CARDIAC CYCLE IN THE FOLLOWING SITUATIONS.

DURING THE T WAVE

REPOLARIZATION OF VENTRICLES

TACHYCARDIA

A HEART RATE OVER 100 BEATS/MIN

BRADYCARDIA

A HEART RATE BELOW 60 BEATS/MIN

FIBRILLATION

RAPID, UNCOORDINATED HEART CONTRACTIONS THAT MAKES HEART USELESS AS A PUMP

WHICH WOULD BE MORE SERIOUS, ATRIAL OR VENTRICULAR FIBRILLATION? WHY?

VENTRICULAR FIBRILLATION, BECAUSE WHEN YOUR IN V-FIB YOUR PRETTY MUCH DEAD UNLESS THEY CAN SHOCK YOUR HEART BACK INTO RHYTHM. WITH ATRIAL FIBRILLATION, IT CAN BE TREATED WITH ANTI-RHYTHMIC DRUGS.

ABNORMALITIES OF HEART VALVES CAN BE DETECTED MORE ACCURATELY BY AUSCULTATION THAN BY ELECTROCARDIOGRAPHY. WHY IS THIS SO?

ABNORMAL HEART VALVES CAUSE EXTRA HEART SOUNDS (S3 AND S4) THAT CAN BE HEARD WITH A STETHOSCOPE. AN ECG JUST MEASURES ELECTRICAL ACTIVITY IN THE HEART, IT REALLY DOESNT HAVE ANYTHING TO DO WITH HOW THE VALVES WORK.