Cardiac Cycle and Conduction

Front

What is the cardiac cycle?

Back

The cardiac cycle is the sequence of events that occur during one heartbeat, including the contraction (systole) and relaxation (diastole) of the heart chambers.

Front

What is the role of the SA node in the cardiac conduction system?

Back

The SA node, or sinoatrial node, is the natural pacemaker of the heart that initiates the electrical impulses that trigger heartbeats.

Front

What is the function of the AV node?

Back

The AV node, or atrioventricular node, receives impulses from the SA node and delays them before passing them to the ventricles, allowing for coordinated contraction.

Front

What are Purkinje fibers?

Back

Purkinje fibers are specialized conductive fibers that distribute electrical impulses throughout the ventricles, causing them to contract.

Front

What happens during ventricular systole?

Back

During ventricular systole, the ventricles contract, pumping blood out of the heart to the lungs and the rest of the body.

Front

What is the sequence of conduction through the heart?

Back

The sequence is: SA node → AV node → AV bundle → Bundle branches → Purkinje fibers.

Front

What is the significance of the Bundle of His?

Back

The Bundle of His, or AV bundle, conducts impulses from the AV node to the bundle branches, playing a crucial role in the heart's electrical conduction system.

Front

What occurs during diastole?

Back

During diastole, the heart muscle relaxes, allowing the chambers to fill with blood.

Front

How does the autonomic nervous system affect heart rate?

Back

The autonomic nervous system regulates heart rate through sympathetic (increases heart rate) and parasympathetic (decreases heart rate) pathways.

Tags

NGSS.HS-LS1-3

Front

What is the difference between systole and diastole?

Back

Systole refers to the contraction phase of the heart, while diastole refers to the relaxation phase.