Heart Cells and Electrical Activity

Flashcards based on lecture notes about the heart's cells and electrical activity.

Conducting Cells

Cells responsible for conducting electrical impulses in the heart.

Contractile Cells

Cells that contract in response to electrical conduction in the heart.

Myocyte/Contractile Cell

The cell type that causes contraction and relaxation of the heart.

Contract and Relax

The electrical impulse sent to the muscle via a nerve ending allows the muscle to do what?

Resting Membrane Potential

The state of a muscle cell when it is not contracting and is at rest.

Threshold

What must be reached before an action potential can fire?

Repolarization Phase

The phase after an action potential when the cell returns to its resting state.

Hyperpolarization

The period where the potassium ion channels are slow to close, resulting in a region below the resting membrane potential.

Sodium-Potassium Pump

The ion channel that uses ATP to pump sodium ions out and potassium ions into the cell.

Early and final Repolarization

The two phases of repolarization which are the early repolarization phase and the final repolarization phase.

Plateau Phase

The feature seen in cardiac muscle cells due to the influx of calcium ions.

Sinoatrial (SA) Node

The natural pacemaker of the heart that fires between 60 to 100 action potentials per minute at rest.

Bradycardia

A heart rate less than 60 beats per minute in an adult.

Tachycardia

A heart rate exceeding 100 beats per minute in an adult.

Atrioventricular (AV) Node

The node located between the atrium and ventricle.

Atrioventricular Bundle (Bundle of His)

The bundle located between the atrium and ventricle after the AV node.

Interventricular Septum

Where are the right and left bundle branches located in the heart?

Purkinje Fibers

Fibers located in the lateral walls of the ventricles.

P Wave

What registers a wave when the atria are depolarizing?

Ventricles

The lower chambers of the heart.

It should be open

What happens to the tricuspid valve during atrial contraction?

Depolarize

What must a ventricle do before contraction?

Mitral Valve

Which valve should be closed when the right ventricle is in contraction?

Semilunar Valves

The valves that need to be open during the Ventricular contraction phase.

Heart Sounds

Due to the closure of heart valves

S1

Due to the closure of AV valves.

S2

Due to the closure of semilunar valves.

How do you calculate Pulse Pressure?

• Pulse pressure is the difference between systolic and diastolic pressure.