PGHY/ANAT 230 Chapters 19

According to the Frank-Starling law

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

During the plateau phase of a cardiac muscle cell's action potential, the membrane stays

depolarized as potassium exits and calcium enters.

The membrane of a contractile cardiac muscle cell contains

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

The atrioventricular (AV) node is located in the

floor of the right atrium.

Most of the calcium that triggers contraction of cardiac muscle comes

from the sarcoplasmic reticulum of the cell.

Cardiac output equals the

heart rate multiplied by stroke volume.

Occlusion of blood vessels tends to lead to

inadequate blood supply and damage to body tissues

Pectinate muscles are found on the

internal walls of the right and left atria.

The posterior interventricular sulcus

is a groove between the ventricles on the back of the heart.

The layer of the heart wall composed of cardiac muscle tissue is the

myocardium.

A drug that decreased calcium levels in a muscle cell and thereby lowered the number of crossbridges formed during the heart's contractions would be a

negative inotropic agent.

The heart valves

permit the passage of blood in one direction.

Large doses of certain stimulants can lead to dangerous increases in heart rates. Such a stimulant is a

positive chronotropic agent.

The opening and closing of the heart valves is caused by

pressure changes of alternating contraction and relaxation during the cardiac cycle.

As blood is pumped out of the heart and into the major arteries leaving the heart, it

pushes against the semilunar valves and opens them.

Each of the receiving chambers of the heart has a wrinkled flaplike extension; the one that is more visible from an anterior view is the

right auricle.

Someone with tachyarrhythmia would be expected to show an abnormally

small Q-T interval.

The metabolic pathways of cardiac muscle make it

somewhat susceptible to heart attack, because it relies so exclusively on aerobic metabolism.

The papillary muscles attach to the cusps of the atrioventricular valves by means of the

tendinous cords.

Cardiac reserve is

the increase in cardiac output an individual is capable of demonstrating during vigorous exercise.

The term "epicardium" is another name for the

visceral layer of the serosal pericardium.

Which segment of the ECG reflects the plateau phase of ventricular muscle cells' action potentials?

S-T segment

Which are differences between cardiac muscle tissue and skeletal muscle tissue? a: The sarcoplasmic reticulum in cardiac muscle is less extensive. b: The sarcoplasmic reticulum in cardiac muscle is more organized. c: Cardiac muscle has intercalated discs; skeletal muscle does not. d: Cardiac muscle has 1 or 2 nuclei per cell; skeletal muscle has multiple nuclei per cell. e: Cardiac muscle has more well-defined terminal cisternae.

a, c, d

The left and right coronary arteries

are functional end arteries because the blockage of one of them leads to tissue death in the area it supplies.

The pulmonary trunk receives blood from the right ventricle and conducts it toward the lung. The pulmonary trunk is a(n)

artery

How many half-moon shaped, pocketlike cusps are found in each semilunar valve?

3

Which of the following would cause a decrease in cardiac output?

An increase in afterload

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

Calcium is entering and potassium is leaving ventricular cells.

Which type of muscle cell exhibits a longer refractory period?

Cardiac muscle cell

The shutting of the semilunar valves occurs during which phase?

Isovolumetric relaxation

From which view is the connection between the pulmonary veins and the heart most visible?

Posterior view

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

Which prenatal structure forms the ascending aorta and pulmonary trunk?

Truncus arteriosus

The tetralogy of Fallot is

a developmental disorder that is a cardiac septal defect.

Which are functions performed by the fibrous skeleton of the heart? a: Separates the atria and ventricles b: Anchors the heart valves c: Provides electrical insulation between the atria and ventricles d: Provides the framework for the attachment of the myocardium e: None of these are true functions of the fibrous skeleton of the heart

a, b, c, d

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

An autorhythmic heart cell is one in which

action potentials fire spontaneoulsy.

Just prior to atrial contraction,

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

Norepinephrine is considered a positive chronotropic agent because it causes

an increase in the firing rate of SA node cells.

Which carries oxygenated blood from the lungs to the heart?

Pulmonary veins

Which circuit of the cardiovascular system is responsible for sending blood to the kidneys, stomach, and pelvic regions?

Systemic circuit

During a cardiac cycle, how many of the four chambers contract at any one time?

2

Which valve prevents the backflow of blood into the left ventricle when the ventricles relax?

Aortic semilunar valve

What would you expect a cardiologist to recommend if there was substantial occlusion to a patient's left coronary artery but not the right coronary artery?

Because this is an important artery, and alternate vascular paths are inadequate, the cardiologist would treat the condition.

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

What is the sequence of events in the transmission of an impulse through the heart muscle? a: AV node b: AV bundle c: SA node d: Through the atria e: Through the ventricles f: Bundle branches g: Purkinje fibers

c, d, a, b, f, g, e

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

calcium pumps that move calcium out of the cell.

The function of the coronary sinus is to

take blood from the coronary circulation to the right atrium.