BIO 244 Chapter 18 Study Guide

Multiple Choice

The (cone)-shaped heart is located within the (_____________), the medial subdivision of the thoracic cavity.

• thoracic cavity

• mediastinum

• abdominal cavity

• dorsal cavity

Fill in the Blank

The broad, flat (____), or posterior surface of the heart, is directed toward the right shoulder.

Fill in the Blank

The (____) of the heart points inferiorly toward the left hip.

Multiple Choice

Select the correct order for the layers of the pericardium starting with the external surface of the heart and ending with the most superficial layer.

(1) Parietal layer of serous pericardium

(2) Fibrous pericardium

(3) Visceral layer of serous pericardium

(4) Pericardial cavity

• 1, 2, 3, 4

• 2, 1, 4, 3

• 2, 3, 4, 1

• 4, 3, 1, 2

• 3, 4, 1, 2

Match

Match the layers of the heart

• The visceral layer of the serous pericardium

• Layer of heart wall that forms the bulk of the heart

• A lining of the heart wall with a sheet of endothelium (simple squamous epithelium}

epicardium

myocardium

endocardium

• epicardium

• myocardium

• endocardium

Multiple Choice

Which layer of the heart wall actually contracts?

• epicardium

• myocardium

• endocardium

Multiple Choice

What type of muscle makes up the myocardium?

• cardiac muscle

• smooth muscle

• skeletal muscle

Match

Match the parts of the heart

• aorta

• pulmonary trunk

• left atrium

• right atrium

a

b

c

d

• a

• b

• c

• d

Match

Match the parts of the heart

• left ventricle

• right ventricle

• inferior vena cava

e

f

g

• e

• f

• g

Multiple Choice

The right side of the heart receives oxygen-poor blood from the body tissues.

• True

• False

Multiple Choice

The blood vessels that carry blood to and from all body tissues form the pulmonary circuit.

• True

• False

Multiple Choice

The atria are discharging chambers.

• True

• False

Multiple Choice

The right ventricle ejects blood into the aorta.

• True

• False

Multiple Choice

The ventricles make up most of the volume of the heart.

• True

• False

Multiple Choice

The pulmonary veins transport oxygen-rich blood from the lungs to the heart.

• True

• False

Multiple Choice

The left ventricle pumps blood into the systemic circuit.

• True

• False

Multiple Choice

The inferior vena cava collects blood draining from the myocardium.

• True

• False

Multiple Choice

The superior vena cava returns blood to the right atrium.

• True

• False

Multiple Choice

The pulmonary trunk routes blood to the body tissues where gas exchange occurs.

• True

• False

Multiple Choice

Bundles of muscle tissue called papillary muscles form ridges in the walls of the right atrium.

• True

• False

Multiple Choice

The left atrium receives blood returning from the pulmonary circuit.

• True

• False

Multiple Choice

The right ventricle forms most of the anterior surface of the heart.

• True

• False

Multiple Choice

The left ventricle forms the base of the heart.

• True

• False

Multiple Choice

The auricles are small, wrinkled pouches that extend from the atria.

• True

• False

Multiple Choice

The _____________________ prevent backflow of blood into the (atria) when the ventricles contract and intraventricular pressure rises.

• semilunar (SL) valves

• atrioventricular (AV) valves

Multiple Choice

The __________________ prevent backflow of blood into the (ventricles) when the ventricles relax and intraventricular pressure falls.

• semilunar (SL) valves

• atrioventricular (AV) valves

Multiple Select

Select the two atrioventricular (AV) valves:

• tricuspid valve

• pulmonary valve

• aortic valve

• bicuspid (mitral) valve

• Blood returning to the heart fills the atria, pressing against the AV valves.

• The increased pressure in the atria forces the AV valves open.

​What causes the AV valves to open?

• Contraction of the ventricles forces blood against the AV valve cusps.

• The increased pressure in the ventricles forces the AV valves close.

​What causes the AV valves to close?

• The chordae tendineae “heart strings” anchor the cusps of the AV valves to the papillary muscles that protrude from the ventricular walls.

• During ventricular contraction, the papillary muscles contract and the chordae tendineae tighten, preventing the valve flaps from everting into the atria.

​What prevents the A V valves from everting (turning inside out) into the atria?

Multiple Select

Select two semilunar (SL) valves?

• aortic valve

• tricuspid valve

• bicuspid (mitral) valve

• pulmonary valve

• As the ventricles contract and the pressure within the ventricles rises, blood is pushed up against the semilunar valves, forcing them to open.

​

​What causes the SL valves to open?

• As the ventricles relax and the pressure within the ventricles falls, blood flows back from the arteries (aorta or pulmonary trunk), pushing on the cusps of the semilunar valves and forcing them to close.

​

​What causes the SL valves to close?

Match

Match the heart valves with their locations:

• Located between the right atrium and the right ventricle

• Located between the right ventricle and the pulmonary trunk

• Located between the left atrium and the left ventricle

• Located between the left ventricle and the aorta

Tricuspid (Right AV) valve

Pulmonary valve

Left AV/Bicuspid/Mitral valve

Aortic valve

• Tricuspid (Right AV) valve

• Pulmonary valve

• Left AV/Bicuspid/Mitral valve

• Aortic valve

Match

Match the heart valves with their functions:

• Prevents backflow into the right atrium

• Prevents backflow into the right ventricle

• Prevents backflow into the left atrium

• Prevents backflow into the left ventricle

Tricuspid (Right AV) valve

Pulmonary valve

Left AV/Bicuspid/Mitral valve

Aortic valve

• Tricuspid (Right AV) valve

• Pulmonary valve

• Left AV/Bicuspid/Mitral valve

• Aortic valve

Fill in the Blank

The ____ (right or left) side of the heart is the systemic circuit pump (pumps blood through the body’s tissues)

Fill in the Blank

The ____ (right or left) side of the heart is the pulmonary circuit pump (pumps blood through the lungs).

Reorder

Put the steps of blood flow through the heart in order starting with the right atrium (oxygen-poor) blood moves through:

• Right atrium through the tricuspid valve

• Blood flows into the right ventricle

• When the right ventricle contracts, blood moves through the pulmonary valve

• The pulmonary trunk divides into the left and right pulmonary arteries, when delivers the blood to the left and right lungs

1

2

3

4

• 1
• 2
• 3
• 4

Reorder

Put the steps of blood flow through the heart in order following gas exchange at the pulmonary capillaries of the lungs. Start with the oxygen rich blood returning to the heart

• Oxygen rich blood returns to the heart via two left and right pulmonary veins

• The blood goes into the left atrium

• The blood goes through the mitral valve to enter the left ventricle

• When the ventricle contracts, blood flows through the aortic valve to enter the aorta (and into the systemic circuit)

1

2

3

4

• 1
• 2
• 3
• 4

Reorder

Put the steps of blood flow through the heart in order starting with the blood leaving the heart through the aortic valve:

• Blood goes through the aortic valve into the aorta

• The blood goes to the body tissues via the systemic circuit

• Gas exchange occurs at the tissues, then the oxygen poor blood goes back to the heart

• The oxygen poor blood returns to the heart via the inferior and superior vena cavae

1

2

3

4

• 1
• 2
• 3
• 4

Multiple Choice

The ______________ returns blood from body regions superior to the diaphragm

• superior vena cava

• inferior vena cava

• coronary sinus

Multiple Choice

The ______________ returns blood from areas of the body below the diaphragm.

• superior vena cava

• inferior vena cava

• coronary sinus

Multiple Choice

In this image, what does the color red signify?

• oxygen-rich blood

• oxygen-poor blood

Multiple Choice

In this image, what does the color blue signify?

• oxygen-rich blood

• oxygen-poor blood

Multiple Choice

Which ventricle has a thicker wall?

• Left Atrium

• Left Ventricle

• Right Atrium

• Right Ventricle

• The left ventricle has a thicker wall than the right ventricle.

• The left ventricle can generate much more pressure than the right ventricle and is a far more powerful pump.)

​Why does the left ventricle have a thicker wall than the right ventricle?

Match

Match the arteries of the heart:

• Right coronary artery

• Right marginal artery

• Posterior interventricular artery

A

B

C

• A

• B

• C

Match

Match the arteries of the heart:

• Anterior interventricular artery

• Circumflex artery

• Left coronary artery

D

E

F

• D

• E

• F

Multiple Choice

The __________________ of the coronary circulation supply the myocardium of the heart with nutrient- and oxygen-rich blood.

• cardiac veins

• coronary arteries

Multiple Choice

The _________________ drain venous blood from the myocardium.

• cardiac veins

• coronary arteries

Multiple Choice

Which vessel empties into the right atrium?

• Great cardiac vein

• Coronary sinus

• Anterior cardiac vein

• Middle cardiac vein

Multiple Choice

What muscle type is this? Cells are long, cylindrical and multinucleate. Cells are striated. Requires stimulation by the nervous system. Absolute refractory period is much shorter than the contraction. Contracts by sliding filament method. Cells have triads and abundant T tubules.

• smooth muscle

• cardiac muscle

• skeletal muscle

Multiple Choice

What muscle type is this? Some cells are self-excitable. The muscle cells contract as a unit. Cells are short, branched and interconnected. It contains intercalated discs. Cells are highly resistant to fatigue. Cells are striated. Contracts using the sliding filament theory.

• smooth muscle

• cardiac muscle

• skeletal muscle

Multiple Choice

_________________ allow ions to pass directly from cell to cell. By electrically connecting the cardiac muscle cells, the flow of ions (current) transmits a wave of depolarization across the entire heart and the myocardium behaves as a single coordinated unit, or functional syncytium.)

• tight junctions

• gap junctions

• desmosomes

Multiple Choice

_________________ anchor neighboring cells together. This keeps adjacent contractile cardiac muscle cells from pulling apart from each other during contraction

• tight junctions

• gap junctions

• desmosomes

Reorder

Put the events in order of excitation-contraction couple in contractile cells of cardiac muscle from start to finish

• A wave of depolarization arrives which causes slow Ca2+ channels to open in the plasma membrane.

• Ca2+ enters the cardiac muscle cell from the extracellular fluid.

• The sarcoplasmi reticulumreleases bursts of Ca2+. Ca2+ binds to the regulatory protein troponin

• Myosin-binding sites are exposed.

• Cross bridge cycling begins.

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

• Cardiac pacemaker cells have an unstable resting membrane potential that continuously (depolarizes) (depolarizes or repolarizes or hyperpolarizes), drifting slowly toward threshold.

• The membrane interior slowly becomes (less) negative as a result of both the closing of (potassium) ion channels and the opening of (sodium) (sodium or potassium or calcium) ion channels.

• These spontaneously changing membrane potentials, called pacemaker potentials represent the first part of an action potential in a typical pacemaker cell.

(1)

• When the threshold voltage of approximately (-40) mV is reached, ion channels open and the explosive entry of (calcium) ions produces (depolarization), the second phase of the action potential.

• In this phase, the membrane potential becomes a (positive) voltage.

(2)

• The third part of the action potential, repolarization occurs when ion channels for calcium inactivate and the ion channels for potassium open.

• The efflux of potassium ions brings the membrane potential to its most negative voltage.

(3)

• The first part of the action potential, called depolarization, occurs when the influx of sodium ions through fast voltage-gated channels causes the membrane interior to rapidly change from (-90) mV to nearly +30 mV (see left vertical axis above). Channel inactivation ends this phase.

(1)

• The plateau phase results from the influx of calcium ions through slow channels.

• This produces a plateau in the action potential tracing.

(2)

(3)

• ​The last part of the action potential called repolarization occurs when the ion channels for calcium ions inactivate and the ion channels for potassium ions open.

• The efflux of potassium ions brings the membrane potential back to its resting voltage.

1. Ensures that contraction lasts long enough to efficiently eject blood from the heart

2. Ensures that the absolute refractory period is long enough to prevent tetanic contractions

​Describe two important consequences of the long plateau phase in the action potential of contractile cardiac muscle cells.

Multiple Choice

The __________ conduction system coordinates the activity of the heart, ensuring that the heart beats as a unit. It also serves as the pacemaker, setting the basic heart rate. It initiates and distributes a wave of depolarization throughout the heart, so that it depolarizes and contracts in an orderly, sequential manner.)

• extrinsic

• intrinsic

Multiple Choice

_______________ innervation of the heart by the autonomic nervous system can increase or decrease the heart rate depending on the needs of the body.)

• extrinsic

• intrinsic

Multiple Choice

The ________________ division of the autonomic nervous system acts as the “accelerator.” Increased sympathetic impulses increase heart rate and the force of contraction.

• sympathetic

• parasympathetic

Multiple Choice

The _______________ division of the autonomic nervous system acts as the “brake.” Increased parasympathetic impulses decrease heart rate.)

• sympathetic

• parasympathetic

Match

Put the heart's electrical conduction system in order:

• Sinoatrial (SA) node

• Atrioventricular (AV) node

• Atrioventricular (AV) bundle

• Right and Left bundle branches

• Subendocardial conducting network (Pekinje fibers)

1

2

3

4

5

• 1

• 2

• 3

• 4

• 5

Multiple Choice

What is the heart’s “pacemaker”?

• Sinoatrial (SA) node

• Atrioventricular (AV) node

• Atrioventricular (AV) bundle

• Right and Left bundle branches

• Subendocardial conducting network (Perkinje fibers)

Multiple Choice

Where is the Sinoatrial (SA) node located?

• The right atrial wall, just inferior to the entrance of the superior vena cava

• The right ventricle, near the tricuspid valve

• The left atrium, just inferior to the entrance of the pulmonary veins

• The left ventricle, just inferior to the aortic valve

Multiple Choice

How long is the pause that occurs at #2?

• 0.05 seconds

• 0.1 seconds

• 0.2 seconds

• 0.3 seconds

• The delay at the atrioventricular (AV) node allows the atria to complete their contractions before the wave of depolarization reaches the ventricles.

• This is important because otherwise, all four chambers would contract at the same time.

​What is the importance of the 0.1 second pause that occurs at the structure indicated by circle 2?

Match

Match the ECG tracing waves

• P wave

• Q

• R

• S

• T wave

1

2

3

4

5

• 1

• 2

• 3

• 4

• 5

Multiple Choice

What electrical event occurs during the P wave?

• depolarization of the atria

• repolarization of the atria

• depolarization of the ventricles

• repolarization of the ventricle

Multiple Choice

What mechanical event is triggered by the P wave?

• contraction of the ventricles

• relaxation of the ventricles

• Contraction of the atria

• Relaxation of the atria

Multiple Choice

What electrical event occurs during the QRS complex?

• depolarization of the atria

• repolarization of the atria

• depolarization of the ventricles

• repolarization of the ventricles

Multiple Choice

What mechanical event is triggered by the QRS complex?

• contraction of the ventricles

• relaxation of the ventricles

• Contraction of the atria

• Relaxation of the atria

Multiple Choice

What electrical event occurs during the T wave?

• depolarization of the atria

• repolarization of the atria

• depolarization of the ventricles

• repolarization of the ventricles

Multiple Choice

What mechanical event is triggered by the T wave?

• contraction of the ventricles

• relaxation of the ventricles

• Contraction of the atria

• Relaxation of the atria

Multiple Choice

Which portion of the ECG also coincides in time with atrial repolarization?

• P wave

• QRS complex

• T wave

• P-R interval

Multiple Choice

How would a nonfunctional SA node affect the appearance of the ECG?

• The order of waves would become random.

• The amplitude (height) of the T wave would increase.

• The P wave would be absent.

• The QRS complex would last much longer.

Match

Match the terms with their definitions:

• Sequence of events during one heartbeat consisting of one complete contraction and relaxation of the atria and the ventricles of the heart.

• Period of the cardiac cycle when a pair of heart chambers (usually ventricles) are contracting

• Period of the cardiac cycle when a pair of heart chambers (usually ventricles) are relaxing

Cardiac cycle

Systole

Diastole

• Cardiac cycle

• Systole

• Diastole

Multiple Choice

Which valves ensure one-way flow of blood from the atria to the ventricles?

• Atrioventricular (AV) valves

• Semilunar (SL) valves

Open: These valve open when the ventricular pressure drops below the atrial pressure. This allows blood to flow from the atria to the ventricles.

Close: These valves close when the ventricular pressure exceeds the atrial pressure. This prevents backflow of blood into the atria.

​

​How AV valves open and close

Open: These valves open when the ventricular pressure exceeds the aortic pressure. This allows blood to flow from the ventricles to the aorta (or pulmonary trunk on right side).

Close: These valves close when the ventricular pressure drops below the aortic pressure. This prevents backflow of blood into the ventricles.

​

​How Semilunar (SL) valves open and close

Multiple Select

During which phase(s) of the cardiac cycle are the ventricles in systole? Select two answers!

• Ventricular filling phase

• Isovolumic contraction phase

• Ventricular ejection phase

• Isovolumic relaxation phase

Multiple Select

During which phase(s) of the cardiac cycle are the ventricles in diastole? Select two answers!

• Ventricular filling phase

• Isovolumic contraction phase

• Ventricular ejection phase

• Isovolumic relaxation phase

Multiple Select

During which phase(s) of the cardiac cycle are all of the heart valves closed? Select two answers!

• Ventricular filling phase

• Isovolumic contraction phase

• Ventricular ejection phase

• Isovolumic relaxation phase

Multiple Choice

What electrical event (and corresponding ECG wave) precedes ventricular contraction?

• depolarization of atria (P wave)

• repolarization of atria

• depolarization of ventricles (QRS complex)

• repolarization of ventricles (T wave)

Multiple Choice

What electrical event (and corresponding ECG wave) precedes atrial contraction?

• depolarization of atria (P wave)

• repolarization of atria

• depolarization of ventricles (QRS complex)

• repolarization of ventricles (T wave)

Multiple Choice

The first heart sound "lub" is associated with the __________.

• opening of the atrioventricular valves

• opening of the semilunar valves

• closing of the atrioventricular valves

• closing of the semilunar valves

Multiple Choice

10. The second heart sound “dup” is associated with the __________.

• opening of the atrioventricular valves

• opening of the semilunar valves

• closing of the atrioventricular valves

• closing of the semilunar valves

Would you use an ECG or a stethoscope to detect an incompetent or insufficient heart valve?

• An incompetent or insufficient heart valve creates a swishing sound as blood backflows or regurgitates because the faulty valve fails to close correctly.

• A heart murmur, such as in this example, is detected by listening to the heart sounds with a stethoscope.

• An ECG detects electrical activity from the heart.

• It would be useful for detecting problems with the intrinsic conduction system.

Match

Match the terms with their definitions:

• The amount of blood pumped out by each ventricle in 1 minute

• The number of heart beats per minute

• The volume of blood pumped out by one ventricle with each heartbeat

Cardiac Output (CO)

Heart Rate (HR)

Stroke Volume (SV)

• Cardiac Output (CO)

• Heart Rate (HR)

• Stroke Volume (SV)

Multiple Choice

Cardiac output is the product of heart rate times _______________

• end systolic volume

• heart rate

• stroke volume

• blood pressure

Multiple Choice

_____________: The amount of blood that collects in a ventricle during diastole

• end diastolic volume (EDV)

• end systolic volume (ESV)

• cardiac output

• stroke volume

Multiple Choice

_____________: The volume of blood remaining in the ventricle after contraction

• end diastolic volume (EDV)

• end systolic volume (ESV)

• cardiac output

• stroke volume

Multiple Choice

____________ = EDV - ESV

• stroke volume

• cardiac output

• heart rate

• preload

Multiple Choice

____________ = Heart Rate (HR) x Stroke Volume (SV)

• stroke volume

• cardiac output

• heart rate

• preload

Calculate cardiac output given the following: heart rate = 65 beats/minute; end diastolic volume = 150 m l/beat; end systolic volume = 50 m l/beat.

Calculate cardiac output given the following: heart rate = 65 beats/minute; end diastolic volume = 150 ml/beat; end systolic volume = 50 ml/beat.

SV = EDV - ESV
SV = 150 ml/beat - 50 ml/beat = 100ml/beat
CO = 65 beats/minutes x 100 ml/beat
CO = 6500 ml/minute or 6.5 L/minute

Match

Match the terms with their definitions:

• The degree to which cardiac muscle cells are stretched just before they contract; determined by the amount of venous return

• The contractile strength achieved at a given muscle length

• The pressure that the ventricles must overcome to eject blood; essentially the back pressure that arterial blood exerts on the semilunar valves

Preload

Contractility

Afterload

• Preload

• Contractility

• Afterload

Multiple Choice

If the End Diastolic Volume (EDV)is increased, what will happen to the stroke volume?

Remember SV = EDV - ESV

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If the heart has decreased contractility, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If the heart has decreased venous return, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If the heart has increased afterload due to hypertension, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If there is increased body movement, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If there is decreased preload, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If there is increased ventricular filling, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If there is increased thyroxine in the blood, what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

If there is decreased end systolic volume (ESV), what will happen to the stroke volume?

• Increase stroke volume

• Decrease stroke volume

Multiple Choice

What is the intrinsic heart rate (number of beats/minute in the absence of autonomic regulation)?

• 50 beats/minute

• 70 beats/minute

• 80 beats/minute

• 100 beats/minute

• 120 beats/minute

• Activation of the sympathetic division during stressful situations increases heart rate above the intrinsic rate.

• The force of contraction also increases.

• The parasympathetic division opposes sympathetic effects and decreases heart rate.

How do the sympathetic and parasympathetic divisions of the autonomic nervous system influence the intrinsic heart rate?

Multiple Choice

What is the normal heart rate?

• 50 beats/minute

• 75 beats/minute

• 80 beats/minute

• 100 beats/minute

• 120 beats/minute

Multiple Choice

Which division dominates at rest?

• parasympathetic

• sympathetic