Heart Physiology in Review

QUESTION:

Reflect

What are the four chambers of the heart?

ANSWER:

The left and right atria and ventricles.

QUIZ QUESTION::

Order the steps of cardiac conduction.

ANSWER CHOICES:

5

3

1

2

4

6

Steps	Order
Impulse generation in the Sinus Node
Atrial depolarization
AV node impulse conduction
Ventricular depolarization begins
Atrial repolarization
Ventricular repolarization

SOLUTION:

Steps	Order
Atrial repolarization	5
AV node impulse conduction	3
Impulse generation in the Sinus Node	1
Atrial depolarization	2
Ventricular depolarization begins	4
Ventricular repolarization	6

What phenomenon is responsible for carrying the electrical signal in the heart?

Heart cell contraction.

Electrons move along a heart cell.

Neurons conduct the electrical signal through various parts of the heart.

Ions moving across the heart cell membrane.

SOLUTION:

Ions moving across the heart cell membrane.

Glossary

• Atria: The upper chambers of the heart that pass blood to the ventricles.
• Ventricles: The main chambers of the heart that pump blood throughout the body
• Depolarization: The movement of charges across a cell membrane that causes the inside of the cell to become less negatively charged.
• Repolarization: The movement of charges across the cell membrane that restore the negative resting charge inside the cell.
• Cardiac conduction system: A group of specialized cardiac cells that send signals to the heart, causing it to contract. The main components that we discussed in this course were the sinoatrial (SA) node and the atrioventricular (AV) node. Other components include the bundle of His, left and right bundle branches, and the Purkinje fibers, which propagate the signal from the AV node throughout the ventricles.
• Sinus node: The natural pacemaker of the heart. Responsible for generating the impulse that causes the heart to beat.
• AV node: Part of the cardiac conduction system that propagates the impulse from the atria to the ventricles after a delay.