AP Spring HW 7 + Quiz 4

Sometimes your patient experiences two ventricular contractions to a single atrial contraction. Which arrhythmia do you think they might have?

Atrial fibrillation

Which of the following is not a possible circulatory route from the heart?

Heart → arteries → capillary bed → vein → capillary bed → arteries → heart

Which of the following is a portal system?

Heart → artery → arteriole → capillary bed → arteriole → capillary bed → venule → vein → heart

Which of the following routes of blood flow is correct?

Heart → conducting artery → distributing artery → arteriole → capillary → venule → medium vein → large vein → heart

What is the correct path of an electrical excitation from the pacemaker to a cardiomyocyte in the left ventricle (LV)?

Sinoatrial (SA) node → atrioventricular (AV) node → atrioventricular (AV) bundle → Subendothelial conducting network → cardiomyocyte in LV

In a normal ECG, the deflection that is generated by ventricular repolarization is called the __________.

T wave

When the sphincters are open, blood will ____________ the capillary bed.

fill

Atrial systole begins __________.

immediately after the P wave

Where are arterial anastomoses, in which two arteries merge, found?

in the coronary circulation

Which vessels have the thickest tunica media?

large arteries

Constriction of these sphincters ____________ the blood flow through their respective capillaries.

reduces

Arteries are sometimes called the __________ vessels of the cardiovascular system because they have strong-resilient tissue structure.

resistance

In the heart, an action potential originates in the __________.

sinoatrial node

Capillary beds have precapillary ____________ at the junction of capillaries and the metarteriole.

sphincters

The SA node *blank* fires at regular intervals. This is because the cells of the SA node do not have a stable *blank* membrane potential like skeletal muscles or neurons. Their membrane potential starts at about *blank* mV and drifts upward. This gradual, upward drift towards a *blank* is called the pacemaker potential. This results from a slow inflow of sodium ions without a compensating outflow of *blank* ions.

spontaneously; resting; -60; depolarization; potassium

Which of the following is the correct sequential path of an action potential in the heart? a) Atrioventricular node, sinoatrial node, atrioventricular bundle, bundle branches, Purkinje fibers b) Purkinje fibers, atrioventricular bundle, atrioventricular node, sinoatrial node, bundle branches c) Atrioventricular bundle, atrioventricular node, sinoatrial node, bundle branches, Purkinje fibers d) Sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers e) Atrioventricular node, sinoatrial bundle, atrioventricular node, bundle branches, Purkinje fibers

d) Sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers

Which term refers to relaxation of the heart?

diastole

When this occurs, blood is ____________ to tissue or organs elsewhere.

diverted

Which of the following is a feature shared by cardiac muscle and skeletal muscle? A. Muscle fiber striations B. Dependence upon nervous stimulation C. Communication via electrical (gap) junctions D. Intercalated discs E. Autorhythmicity

A. Muscle fiber striations

Atrial depolarization causes the _________.

P wave

An extended period of time between the P wave and the QRS complex may indicate which of the following?

The signal is taking too long to get to the AV node.

Which of the following is NOT a characteristic of cardiac muscle cells? They depend almost exclusively on aerobic respiration. They are rich in glycogen. They have larger than average mitochondria. They are very rich in myoglobin. They have about the same endurance as skeletal muscle fibers.

They have about the same endurance as skeletal muscle fibers.

Action potentials are carried by the subendocardial conducting network (Purkinje fibers) from the bundle branches to the ventricular walls. T or F?

True

Cardiac muscle is not prone to fatigue because it makes little use of anaerobic fermentation or the oxygen debt mechanism. T or F?

True

In the ventricles, the action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricle walls. T or F?

True

Alternative routes of blood supply are called __________.

anastomoses

Which of the following is true concerning the heart's conduction system? a) Action potentials pass slowly through the ventricle wall. b) Action potentials pass slowly through the atrioventricular bundle. c) Action potentials pass slowly through the atrioventricular node. d) Action potentials pass slowly through the bundle branches. e) Action potentials pass slowly through the Purkinje fibers.

c) Action potentials pass slowly through the atrioventricular node.

Blood usually passes through one network of capillaries from the time it leaves the heart until the time it returns, but there are exceptions, notably the __________.

portal systems and anastomoses

The long absolute refractory period of cardiomyocytes _________.

prevents tetanus

The outermost wall of an artery or vein is called the __________ and in large arteries and veins contains the __________.

tunica externa; vasa vasorum

What are the afferent vessels that carry blood back to the heart?

veins