Week 4 Semester 2

Electrocardiogram (ECG, EKG)

A recording of electrical changes that occur in the myocardium during the cardiac cycle

Tachycardia

Abnormally fast heartbeat, >100 beats/min at rest

Bradycardia

Abnormally slow heartbeat, < 60 beats/min at rest

The force the heart must overcome to pump blood is known as ________.

Afterload

Why will the Dr attach these 4 new blood vessels to the Aorta?

Aorta pumps out freshly O2 blood and this will route it down to feed the heart muscle

The Dr. is giving the pt cold blood every so often to keep it "preserved" during surgery. Why does the heart start to "wiggle" with this shot of cold blood?

As it warms, the heart is using the O2 in the blood

Most blood enters the ventricle during ________.

Atrial diastole

In which septum is it normal to find openings in the adult?

Atrioventricularr

Premature beat

Beat that occurs before expected in normal cardiac cycle; often originates from ectopic regions of heart (other than SA node)

Which primitive area of the heart will give rise to the right ventricle?

Bulbus cordis

Which of the following is a positive inotrope?

Ca2+

The influx of which ion accounts for the plateau phase?

Calcium

The two tubes that eventually fuse to form the heart are referred to as the ________.

Cardiogenic tubes

The first heart sound represents which portion of the cardiac cycle?

Closing of the atrioventricular valves

Ectopic Pacemaker

Damage to SA node may lead to AV node taking over, and act as secondary pacemaker; 40-60/min, instead of 70-80

Which of the following events is recorded in an ECG tracing?

Depolarization of ventricular muscle.

The earliest organ to form and begin function within the developing human is the ________.

Heart

In a healthy young adult, what happens to cardiac output when heart rate increases above 160 bpm?

It decreases.

What happens to preload when there is venous constriction in the veins?

It increases

The myocardium would be the thickest in the ________.

Left Ventricle

The cardiovascular centers are located in which area of the brain?

Medulla oblongata

Of the three germ layers that give rise to all adult tissues and organs, which gives rise to the heart?

Mesoderm

Which of the following is unique to cardiac muscle cells?

Only cardiac muscle is capable of autorhythmicity

Which component of the heart conduction system would have the slowest rate of firing?

Purkinje fibers

An ECG tracing reveals upright P waves preceding each QRS complex, but they have varied shapes and sizes. The QRS complexes are narrow but the R-R intervals are irregular. Which of the following can be concluded regarding this rhythm?

The AV node or common bundle of His is pacing the heart.

An ECG tracing reveals mostly normal cycles, but occasionally a single isolated QRS complex appears following a T wave. These extra complexes have a wide, bizarre shape but they are all similar. Which of the following would be an accurate explanation for these bizarre complexes?

They are premature complexes generated by multiple ectopic pacemakers in the ventricles.

The pulmonary trunk and aorta are derived from which primitive heart structure?

Truncus arteriosus

Ventricular relaxation immediately follows ________.

Ventricular repolarization

Major components of the cardiac conduction system

Whorled networks of muscle in walls of ventricles; when Purkinje fibers stimulate muscle cells, ventricles contract with twisting motion

myocardial contractile cells

bulk of the cells in the atria and ventricles; conduct impulses and are responsible for contractions that pump blood through the body

He said to run blood through a tube for too long changes the way blood coagulates. What does coagulate mean?

clots

The gradual blockage of the coronary arteries by the buildup of cholesterol is called..........

coronary artery disease/ heart attack

P wave

depolarization of the atria; prior to atrial contraction

QRS complex

depolarization of the ventricles; prior to ventricle contraction

Which of the following is not important in preventing backflow of blood?

endocardium

Purkinje cells

flat cells in sequential planes, in the cerebellar cortex, parallel to one another generally; much smaller than the contractile cells and have few of the myofibrils or filaments needed for contraction.

myocardial conducting cells

form the conduction system of the heart

What are things that can happen when the muscle does not receive enough oxygen from a coronary artery due to its blockage?

heart attack or chest discomfort

What is the cardiopulmonary bypass machine?

it withdraws blood and oxygenates it so the heart doesn't have to work for about an hour or two

Which valve separates the left atrium from the left ventricle?

mitral

sinus rhythm

normal heartbeat triggered by the SA node

second degree block

occurs when some impulses from the SA node reach the AV node and continue, while others do not. In this instance, the ECG would reveal some P waves not followed by a QRS complex, while others would appear normal

T wave

repolarization of ventricles; prior to ventricle relaxation

An ECG tracing reveals several P waves that are not followed by QRS complexes, but all remaining cycles have PR intervals that measure 0.16 mm. Which of the following can be concluded regarding this rhythm?

second degree block

atrioventricular (AV) node

specialized myocardial conductive cells, located in the inferior portion of the right atrium within the atrioventricular septum

Which of the following lists the valves in the order through which the blood flows from the vena cava through the heart?

tricuspid, pulmonary semilunar, bicuspid, aortic semilunar

Why is using a vein from the leg as the bypass tube less successful than using an artery from the chest area?

veins are not under high pressure like arteries and will need to learn to "push" blood

Artificial Pacemaker

Device used to treat disorders of cardiac conduction system; implantable and battery-powered

Fibrillation

Uncoordinated, chaotic contraction of small areas of myocardium Atrial fibrillation not life-threatening; ventricular fibrillation is often fatal

The cardiac cycle consists of a distinct relaxation and contraction phase. Which term is typically used to refer ventricular contraction while no blood is being ejected?

Isovolumic contraction

flutter

Rapid, regular contraction of a heart chamber, 250-350 beats/min

Arrhythmias

altered heart rhythms

The ________ layer secretes chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictors.

Endocranium

Which portion of the ECG corresponds to repolarization of the atria?

None of the above: atrial repolarization is masked by ventricular depolarization

Which chamber initially receives blood from the systemic circuit?

Right Atrium

The coronary arteries, extend out from the aorta to deliver oxygen to the heart ________.

chambers

first degree block

indicates a delay in conduction between the SA and AV nodes. This can be recognized on the ECG as an abnormally long PR interval

heart block

interference with normal conduction of electrical impulses that control activity of the heart muscle

What is the physician assistant doing?

taking vein from the leg

What part of the heart pumps with higher pressure, the left or the right?

the left

sinoatrial (SA) node

the pacemaker; highly specialized, neurological tissue impeded in the wall of the right atrium; responsible for initiating electrical conduction of the heartbeat, causing the atria to contract and firing conduction of impulses to the AV node

third degree block

there is no correlation between atrial activity (the P wave) and ventricular activity (the QRS complex)