Mastering (1) Chapter 17

Certain drugs used to treat dysrhythmias, called local anesthetics, work by blocking voltage gated sodium ion channels and slowing the entry of sodium ions into the cell during an action potential. What effects would you see?

Decrease depolarization of the cell

What generates an action potential, which spreads to atrial cells and the AV node?

Sinoatrial (SA) node

What happens before the action potential is conducted to the AV bundle and then to the right and left bundle branches?

The Atrioventricular (AV) node delay

Which of the following happens immediately after the P wave?

The atria contract.

What vessel delivers oxygenated blood to systemic capillaries for gas exchange?

aorta

The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the:

atria.

Which hormone decreases cardiac output by decreasing blood volume and preload?

atrial natriuretic peptide (ANP)

Autorhythmicity in the heart is the responsibility of:

cardiac pacemaker cells.

What largely determines preload?

end-diastolic volume (EDV)

The apex of the heart is __________.

inferior

What characteristic differentiates cardiac muscle cells from skeletal muscle cells?

intercalated discs

What surface groove separates the right and left ventricles?

interventricular sulcus

Unlike skeletal muscle action potentials, cardiac muscle action potentials __________.

involve calcium voltage-gated channels

The pulmonary circuit involves blood flow from the heart to the:

lungs.

Which of the following vessels carries oxygenated blood?

pulmonary vein

What vessel(s) deliver oxygenated blood to the left atrium?

pulmonary veins

What normally serves as the pacemaker of the entire heart?

sinoatrial (SA) node

What two values are needed in order to calculate cardiac output (CO) for a ventricle?

stroke volume (SV) and heart rate (HR)

The vessels that deliver oxygen to the tissues of the body are part of the __________.

systemic circuit

What will immediately follow the phase of the cardiac cycle when the End-systolic volume is low?

the atrioventricular valves open.

Afterload is described as:

the force the ventricles must overcome to eject blood into their respective arteries

The right side of the heart pumps deoxygenated blood into __________.

the lungs

The aortic valve closes when __________.

the pressure in the left ventricle falls below aortic pressure

What valve prevents the backflow of blood from the right ventricle into the right atrium?

tricuspid valve

Blood from the systemic circuit returns to the heart via the __________.

venae cavae

During what phase does blood flow from the ventricles into the pulmonary trunk and aorta?

ventricular ejection phase

What does the Purkinje fiber system consist of?

-AV bundle -Right bundle branch -Left bundle branch -Purkinje fibers

A patient has a heart rate of 70 beats per minute, an EDV of 110 ml, and an ESV of 70 ml. What is the patient's cardiac output?

2.8 L/minute

The ___ _____ spreads from the bundle branches along the purkinje fibers to the ______ _____ of the ventricles.

Action potential; Contractile cells

In regards to the pressure vs time graph dealing with the cardiac cycle, at what point does the Aortic valve open?

B

Heart tissue dies during a myocardial infarction (MI), and a person's survival and recovery depend on the extent of cell death and the chamber(s) involved. In which chamber would the loss of function be most damaging to survival?

Left Ventricle