Heartbeats

What is the primary misconception about the use of defibrillators in cardiac arrest?

• They can only be used by doctors

• They restart a stopped heart

• They are used to perform CPR

• They stop the heart to reset its rhythm

How are cardiac muscle cells different from skeletal muscle cells?

• Cardiac cells are larger and multinucleate

• Skeletal cells have more mitochondria

• Skeletal cells are interconnected and branched

• Cardiac cells are interconnected and have one or two central nuclei

What percentage of a cardiac cell is made up of mitochondria?

• 5 to 10 percent

• 40 to 50 percent

• 25 to 35 percent

• 10 to 15 percent

What is the function of pacemaker cells in the heart?

• To contract the heart muscle

• To generate their own electrical impulses

• To filter blood

• To pump blood throughout the body

What causes the cells in the sinoatrial node to fire off action potentials?

• External electrical stimulation

• Leaky sodium and potassium channels

• Signals from the brain

• Mechanical pressure

Why is there a delay when the electrical signal reaches the AV node?

• To slow down the heart rate

• To generate a stronger electrical impulse

• To give time for the atria to finish contracting

• To allow the ventricles to contract first

What is the role of the AV node in the heart's electrical system?

• To delay the signal, allowing the atria to contract before the ventricles

• To generate the heart's initial electrical impulse

• To filter the blood before it enters the ventricles

• To pump blood into the atria

What is the main purpose of a defibrillator?

• To provide oxygen to the heart

• To pump blood manually

• To correct fibrillation by resetting the heart's rhythm

• To increase the heart rate

What analogy is used to describe the function of a defibrillator?

• Turning off a light switch

• Restarting a computer

• Conductor silencing an orchestra

• Resetting a clock

Why can't CPR correct fibrillation on its own?

• It only works on healthy hearts

• It's only a temporary solution

• It can't generate electrical impulses

• It doesn't provide enough oxygen