Chapter 19 KIN224 A

The inferior, conical end of the heart is called the

Apex

During the S-T segment, what is occurring within cardiac muscle cells?

Calcium is entering and potassium is leaving ventricular cells.

Which of the following is not one of the three main factors influencing stroke volume?

Chronotropic agents

Around day 21 of development the primitive heart begins to beat. At this stage it contains the four chambers: two atria and two ventricles.

False

What are the cell-to-cell contacts of the cardiac muscle fibers called?

Intercalated discs

What part of the cardiac conduction system is located in the posterior wall of the right atrium, adjacent to the entrance of the superior vena cava?

SA node

Deep to the interventricular sulci is the thick muscular wall that divides the left and right ventricles, known as the interventricular

Septum

Which circuit of the cardiovascular system includes the left ventricle and aorta?

Systemic Circuit

Sympathetic innervation of the heart arises from the ________ segments of the spinal cord.

T1-T5

Normally, the left and right ventricles eject the same amount of blood.

True

The tetralogy of Fallot is

a developmental disorder that is a cardiac septal defect.

Which can be used to characterize blood flow in the human body? a: There is a unidirectional blood flow. b: Arteries always carry oxygenated blood. c: Veins always carry deoxygenated blood. d: Arteries carry blood away from the heart. e: Veins carry blood toward the heart.

a,d,e

Just prior to atrial contraction,

all four chambers are at rest and AV valves are open.

According to the Frank-Starling law

as the volume of blood entering the heart increases, ventricular contractions become more forceful.

The property that allows the heart to initiate each heartbeat itself is called

autorhythmicity

For the repolarization phase of an SA nodal cell action potential

calcium channels close and potassium channels open.

The membrane of a contractile cardiac muscle cell contains

fast voltage-gated sodium channels and slow voltage-gated calcium channels.

Coronary vessels are open when the heart is

relaxed

The posterior interventricular artery is a branch off of the

right coronary artery.

The term "epicardium" is another name for the

visceral layer of the serosal pericardium