Chpt 19. HW

What structures make up the general structure of cardiac muscle cells? Check all that apply.

(X) One or two central nuclei (X) Intercalated discs (X) Sarcoplasmic reticulum

Check all that are characteristics of cardiac muscle.

-Cells are short and branching. -Cells have one or two nuclei in the center of the cell.

Check all that are a function of the pericardium.

1) Prevent the heart from overfilling with blood 2) Aid the heart in the strength of contractions 3) Create a near-frictionless environment through the production of serous fluid

Match the component of the heart wall with the correct explanation or definition. 1. Thin serous membrane of the outer surface of the heart 2. Thick middle layer of the heart 3. Covers surfaces of the heart valves 4. Composed of cardiac muscle cells 5. The inner surface of the heart 6. Also known as the visceral pericardium

1. Epicardium 2. Myocardium 3. Endocardium 4. Myocardium 5. Endocardium 6. Epicardium

Match the component of the electrocardiogram to the correct definition.

1. P wave - Atrial depolarization 2. QRS complex - ventricular depolarization 3. T wave - ventricular repolarization 4. PQ segment - atrial contracation or atrial systole 5. ST segment - ventricular contractions or ventricular systole

Match the vessel with its associated chamber. 1. Inferior and superior vena cava 2. Pulmonary trunk 3. Pulmonary veins 4. Aorta

1. Right Atrium 2. Right Ventricle 3. Left Atrium 4. Left Ventricle

Please match the event in the cardiac cycle with the corresponding component of an ECG.

1. Ventricles depolarize and contract QRS complex correct 2. Atria depolarize and contract P wave correct 3. Ventricles repolarize and relax T wave correct

Indicate whether each statement is true or false. 1. During the refractory period of cardiac muscle, the cell is likely to generate another action potential. (Click to select) True False 2. The plateau phase of the action potential in cardiac muscle delays repolarization to the resting membrane potential; therefore the refractory period is prolonged. (Click to select) True False

1.False 2.True

Indicate whether each statement is true or false. 1. The resting membrane potential of cardiac muscle cells depends on a low permeability of the plasma membrane to sodium and potassium and a higher permeability to calcium. (Click to select) True False 2. Action potentials in cardiac muscle last longer than those in skeletal muscle. (Click to select) True False 3. In skeletal muscle there is a plateau phase, a period of slow repolarization, that is not found in cardiac muscle. (Click to select) True False

1.False 2.True 3 False

Match the heart valve with its description.Match the heart valve with its description. 1. Between left atrium and left ventricle 2. Between right ventricle and pulmonary trunk 3. Between right atrium and right ventricle 4. Between left ventricle and ascending aorta

3 - Tricuspid valve 2 - Pulmonary semilunar valve 1 - Bicuspid valve 4 - Aortic semilunar valve

Match the specific area of the heart on the left side supplied by the coronary artery branch on the right. 1) Left atrium and ventricle 2) Anterior surface of both ventricles 3) Right border of the heart 4) Posterior surface of both ventricles

3) Circumflex 2) Anterior interventricular 1)Marginal 4) Posterior interventricular

Which are characteristics of the heart when it is at rest prior to atrial contraction (atrial systole)?

AV valves are open. All four heart chambers are at rest. open. Passive filling of the ventricles is under way.

What are the primary variables influencing stroke volume (SV)? Check all that apply.

Afterload Venous return or preload Contractility or intropic agents

Left ventricular contraction propels blood through which valve?

Aortic valve

What are the primary blood vessel types and their functions? Check all that apply.

Arteries carry blood away from the heart. Veins carry blood back to the heart. Capillaries are the sites of exchange between the blood and the lungs or body cells.

Select all that influence autonomic reflex activity from the cardiac center.

Baroreceptors Chemoreceptors Atrial stretch

What is the correct order of mechanical events associated with cardiac muscle contraction?

Calcium entry into the sarcoplasm, calcium binds to troponin, muscle contracts, closing of calcium channels, calcium released from troponin, muscle relaxes

What are the ion channels associated with cardiac muscle cells? Check all that apply.

Calcium pumps that concentrate more calcium outside the cell Fast voltage-gated sodium channels Sodium/potassium pump

What variables determine the effects on cardiac output?

Changes in both HR and SV

When blood is flowing out of the left ventricle, the bicuspid valve is __________ and the aortic semilunarvalve is __________.

Closed; open

Excess potassium ions in cardiac tissue will cause the heart rate and stroke volume to

Decrease

Cell-to-cell junctions, called intercalated discs, contain distinct structural features called gap junctions and

Desmosomes

Atrial contraction accounts for most of the ventricular filling.

False

Cardiac muscle tissue contains fewer mitochondria than are found in skeletal muscle tissue.

False

In modifying cardiac activity, the parasympathetic innervation comes from the cardioacceleratory center in the brain and the sympathetic innervation comes from the cardioinhibitory center in the brain.

False

Pulmonary arteries carry highly oxygenated blood.

False

The audible heart sounds are caused by the contraction of the atria and ventricles.

False

The coronary sinus is a modified vein that collects venous blood from all areas of the heart and drains it directly into the left atrium of the heart.

False

The only arteries in the body that carry-poor blood are the coronary arteries

False

When the heart is at rest prior to atrial contraction (atrial systole), one of the primary heart characteristics is the AV valves are closed.

False

What are the series of events in the SA nodal cells that directly cause autorhythmic contraction of cardiac muscle cells? Check all that apply.

Fast voltage-gated sodium channels open, causing depolarization after threshold has been reached. Slow voltage-gated sodium channels open, causing a slow depolarization to threshold. Voltage-gated potassium channels open, causing repolarization.

Select all that are coronary veins or any structure associated with coronary veins.

Great cardiac vein Coronary sinus Middle cardiac vein

What are the individual ion contributions to the resting membrane potential (RMP) of the SA nodal cells? Check all that apply.

Greater concentration of K+ inside the cell Calcium (Ca2+) gradient with more calcium outside the cell Greater concentration of Na+ outside the cell What are the primary

Given that cardiac output equals ____________, there are only two ways to change it: change the heart rate or change the stroke volume.

HR X SV

A function of the fibrous skeleton is to anchor ________ by forming supportive rings at their attachment points.

Heart Valves

Select all that are true regarding ventricular balance.

If stroke volume is not the same in each ventricle, edema may result. The left ventricle is stronger than the right

Which of the following are considered events of the cardiac cycle?

Isovolumetric relaxation Atrial contraction and ventricular filling Ventricular ejection Isovolumetric contraction

The wall of the __________ is much thicker than any other chamber in the heart which allows for stronger contractions to pump blood through the systemic circulation.

Left Ventricle

Which of the following is the region of the thoracic cavity where the heart is located?

Mediastinum

The right side of the heart pumps blood through vessels to the lungs and back to the left side of the heart through the __________ circulation.

Pulmonary Circulation

What are the structures included in the heart's conduction system? Check all that apply.

Purkinje fibers Atrioventricular bundle Atrioventricular (AV) node Sinoatrial (SA) node

Oxygen-poor blood enters which chamber of the heart

Right atrium

What is the correct order of spread of the action potential through the heart's conduction system?

SA node, AV node, AV bundle, Purkinje fibers/cell gap junctions

Check all that occur during ventricular systole.

The semilunar valves open to allow blood to flow into the large arteries. The AV valves close to prevent backflow of blood into the atria.

Which of the following is not true for ventricular systole?

The ventricles relax

A function of the fibrous skeleton is to provide electrical insulation between atria and ventricles.

True

Action potentials are carried by the Purkinje fibers from the bundle branches to the ventricular walls.

True

Autonomic influence on heart rate is controlled by reflexes.

True

Cardiac output (CO) is equivalent to heart rate (HR) multiplied by stroke volume (SV).

True

Cardiac reserve can be simply defined as an increase in cardiac output above its level at rest.

True

SA nodal cells are unique in that they exhibit autorhythmicity, meaning they are capable of depolarizing and firing an action potential spontaneously without any external influence.

True

Serous fluid secreted by both the parietal and visceral layers of the pericardium, and released into the pericardial cavity, lubricates the membranes and facilitates the almost frictionless movement of the heart when it beats.

True

The P wave of the ECG coincides with ventricular filling.

True

The action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricular walls.

True

The function of the cardiovascular system is to maintain adequate perfusion of all body tissues.

True

The general function of the cardiovascular system is to transport blood throughout the body to allow the exchange of respiratory gases, nutrients, and waste products between the blood of capillaries and body cells, through the continual pumping action of the heart and vessels.

True

The mechanical events of cardiac muscle contraction are almost identical to the events of skeletal muscle contraction.

True

The ventricles begin to fill during ventricular diastole

True

During which event of the cardiac cycle does aortic pressure reach its maximum?

Ventricular ejection filling

In cardiac muscle, after the plateau phase and at the beginning of replolarization,

Voltage-gated potassium channels open.

In cardiac muscle, after the plateau phase and at the beginning of repolarization,

Voltage-gated potassium channels open.

During the depolarization phase of cardiac muscle

Voltage-gated sodium channels open.

Which of the following is true concerning the heart conduction system?

action potentials pass slowly through the atrioventricular node.

The difference between the maximum and resting cardiac output is called

cardiac reserve

Because the ventricular myocardium is compressed during ventricular _______, most coronary flow occurs during ventricular _______.

contraction; relaxation

The external layer of the heart wall is the

epicardium

The refractory period of skeletal muscle is longer than for cardiac muscle.

false

The pericardium consists of a tough, fibrous connective tissue outer layer called the __________ pericardium.

fibrous

The __________ is a low-pitched sound caused by vibration of the atrioventricular valves and surrounding fluid as the valves close at the beginning of ventricular systole.

first heart sound

How many pulmonary veins are there?

four

As the exercise progresses, muscular activity __________ venous return. This increases the _________ on the right ventricle.

increases; preload

Oxygenated blood flows from the __________ to the __________ before being pumped into the systemic circulation.

left atrium, left ventricle

The sinoatrial (SA) node is referred to as the _____________ of the heart.

pacemaker

The inner layer of the serosal pericardium is a thin, transparent layer of simple squamous epithelium called the __________ pericardium.

parietal

Coronary arteries are _____ when all four heart chambers are relaxed.

patent

In the right atrium, the auricle and anterior wall exhibit obvious muscular ridges called

pectinate muscles

If the right ventricle begins to pump an increased amount of blood, this soon arrives at the left ventricle, stretches it more than before, and causes it to increase its stroke volume and match that of the right. This is an example of

preload

The cells of the ___________ act as the heart's pacemaker, which establishes the pace for cardiac activity.

sinoatrial (SA) node

In the heart, an action potential originates in the

sinoatrial node

The sequence of travel by an action potential through the heart is

sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers.

In the heart, an action potential originates in the

sinoatrial node.

Without a plateau extending the refractory period in cardiac muscle, sarcomeres might be stimulated so quickly that they would contract and not relax and instead would experience a sustained contraction, also called

tetany

The __________ valve is between the right atrium and right ventricle.

tricuspid

The right atrioventricular valve is also called the

tricuspid valve

The atrioventricular valves open during...

ventricular diastole

The semilunar valves close during...

ventricular diastole

During which event of the cardiac cycle do the atria both relax and contract?

ventricular filling