Heart
Describe the coronary circulation.
. The heart is supplied and drained by a set of blood vessels The right and left coronary arteries branch off the ascending aorta and deliever oxygenated blood to the coronary capillaty beds where Generally, majority of the
End-diastolic volume (EDV) for each ventricle at the end of atrial systole is normally about:
120 ml.
transmit 1. atrioventricular (AV) bundle 2. Purkinje fibers 3. sinoatrial (SA) node 4. right and left bundle branches 5. contractile cells of cardiac muscle tissue 6. atrioventricular (AV) node A)
3, 6, 1, 4, 2, 5
59) The amount of blood remaining in each ventricle at the end of the ventricular ejection phase is normally about:
50 ml.
Calculate cardiac output if the heart rate is 85 beats/minute, end-diastolic volume (EDV) 130 ml, and end-systolic volume (ESV) is 60 ml.
5950 ml/min
Calculate the stroke volume (SV) if end-systolic volume (ESV) is 50 ml and the end- diastolic volume (EDV) in a resting heart is 110 ml.
60 ml
69) Calculate the cardiac output if the heart rate is 100 beats per minute and the stroke volume 65 ml.
6500 ml/min
How much blood is pumped from each ventricle during the ventricular ejection phase?
70 ml
Stroke volume averages about:
70 ml per heartbeat
Which of the following is a chronotropic agent that decreases heart rate?
Acetylcholine
Trace the pathway of blood flow through the heart. Begin and end the pathway with thed systemic capillaries.
Answer: The blood flow through the heart is as follows: 1) Systemic capillaries deliver oxygen to body cells. 2) Systemic veins return deoxygenated blood to the right atrium. 3) Blood passeso from the right atrium through the tricuspid valve to the right ventricle. 4) The right ventricle pumps blood through the pulmonary valve to the pulmonary trunk. 5) The pulmonary trunk delivers blood to the right and left pulmonary arteries and then pulmonary capillaries of the left and right lungs, where blood becomes oxygenated. 6) The pulmonary veins return oxygenated blood to the left atrium. 7) Blood passes from the left atrium through the mitral (bicuspid) valve to the left ventricle. 8) The left ventricle pumps blood through the aortic valve the aorta. The aorta delivers blood to the systemic arteries and then capillaries. Bloom's Taxonomy: 3-4) Applying/. zing Learning Outcome: 17.2.5
Explain how to calculate cardiac output (CO).
Answer: To determine cardiac output for a ventricle, we need to know both its stroke volume and heart rate. Stroke volume (SV) can be easily calculated by subtracting the amount of blood in the ventricle at the end of a contraction (the end-systolic volume, or ESV) from the amount of blood in the ventricle after it has filled during diastole (end-diastolic volume, or EDV). In an average heart, the resting stroke volume is equal to about 70 ml while the resting heart rate (HR) averages 60-80 cardiac cycles per minute. In summary, the calculation for cardiac output is: CO = HR x SV. Bloom's Taxonomy: 3-4) Applying/Analyzing
Describe the pathway of the action potential through the cardiac conduction system.
Answer: Under normal conditions, the sinoatrial (SA)bgenerates an action potential that spreads to the atrioventricular (AV) node. Conduction slows once the action potential reaches the AV node and bundle due to a low number of gap junctions between AV nodal cells and presence of nonconducting fibrous skeleton that surrounds the AV node The action potential is conducted from the AV bundle to the right atria depolarize and contract before the ventricles, giving the ventricles time to fill with blood. During this time the artria Depolarize and contract before the ventricles giving the ventricles time to fill with blood. The action potential is conducted from AV bundle to the right and left bundle branches. depolarization spreads to the Purkinje fibers and then to the cardiac contractile muscle cells of the ventricles As a result the ventricles contract and blood is ejected from the heart through the aorta and pulmonary trunk.
The heart is situated in the middle of the thoracic cavity in a region known as the:
B) mediastinum. cavity.
Both the left and right atria receive blood from:
C) veins
Predict the effects of hypocalcemia (low blood calcium ion levels) on the strength and length of contraction in a cardiac contractile cell.
Calcium ions normally enter the cardiac contractile cells as potassium ions continue leave during the plateau phase in order to slow the heart rate and allow the heart to fill with blood. Normally, as calcium ions enter and potassium ions leave, the net membrane potential remains largely unchanged. However, in the case of hypocalcemia, the balance of ions enterin and leaving would be disturbed. Since more potassium ions would be leaving than calcium ior entering, the cardiac contractile cell would not able to maintain a net charge of 0 mV. Thus, th length of the action potential would be shorter, the contraction potentially less forceful, and the heart would have less of an opportunity to fill with blood between action potentials.
Explain how cardiac contractile cells differ from cardiac pacemaker cells.
Cardiac Cardiac contractile cells are striated cardiac muscle cells that respond to excitation from pacemaker cells by conducting an action potential and contracting cardiac pacemaker cells are noncontractile and monstriated cardiac muscle cells that coordinate electrical avtivity rhymically they sponanously generate action potential that trigger cardiac contractule cells to have action potential known as autorhythmicity Cardiac pacemaker cells do Not require stimulation from the nervous system to generate action potential
What surface groove separates the right and left ventricles?
D) interventricular sulcus
An electrocardiogram (ECG) shows extra P waves. Determine and discuss the part of the conduction payhway that is not working
Extra P waves indicate that some action potentials pathway (AV) node at all. Extra P waves are characteristic of from the sinoatrial (SA) node are not ois viluls on eole heart block.
conduction pathway that is not working. An electrocardiogram (ECG) shows extra waves. Determine and discuss the part of the conduction pathway that is not working
Extra p waves indict that some wction potentials from the sinoatrial node are not being conducted through the antrioventricular node at all. Extra p waves are charactristic of heart block
There are two phases of the cardiac cycle in which all four heart valves are open: the isovolumetric contraction phase and the isovolumetric relaxation phase.
FAILSE
Desmosomes present between adjacent cardiac muscle cells allow ions to rapidly pass from one cell to another, permitting communication among cardiac muscle cells.
FALSE
Stroke volume (SV) can be calculated by subtracting the end-diastolic volume (EDV) from the end-systolie volume (ESV).
FALSE
There are two phases of the cardiac cycle in which all four heart valves are open: the isovolumetric contraction phase and the isovolumetric relaxation phase.
FALSE
Desmosomes present between adjacent cardiac muscle cells allow ions to rapidly pass from one cell to another premitting communication among cardiac muscle cells
False
From superficial to deep, the pericardial sac consists of the fibrous pericardium, pericardium, parietal pericardium, and the epicardium.
False
From superficial to deep, the pericardial sac consists of the fibrous pericardium, visceral pericardium, parietal pericardium, and the epicardium.
False
129) Calculate cardiac output given an end-diastolic volume of 140 ml, an end-systolic volume of 60 ml, and a heart rate of 85 beats/minute.
First, determine stroke volume. Stroke volume can be easily calculated by subtracting the amount of blood in the ventricle at the end of a contraction (the end-systolic volume, or ESV) from the amount of blood in the ventricle after it has filled during diastole (end-diastolic volume, or EDV). SV = EDV - ESV = 140 ml - 60 ml = 80 ml Next, determine cardiac output. To find the cardiac output, you simply multiply the heart rate by the stroke volume. CO = HR x SV 85 beats/minute x 80 ml = 6800 ml/min (or 6.8 L/min) Bloom's Taxonomy: 5-6) Evaluating/Creating Learning Outcome: 17.5.1
What best describes the Frank-Starling law?
Frank-Starling The Frank-Starling law states that the more the ventricular muscle cells are stretched, the more forcefully they contract.
Coronary circulation involves the delivery of oxygenated blood to the:
Heart
B
Identify T waves
F
Identify the P-R interval
E
Identify the S-T segment
D
Identify the complex representing ventricular depolarization
G
Identify the interval representing the entire duration of a ventricular action potential
C
Identify the interval that can be used to measure heart rate
K
Identify the interventricar septum
G
Identify the mitral (bicuspid) valve
I
Identify the papillary muscle
E
Identify the pulmonary trunk
A
Identify the wave representing depolarization of all cells within the atria except the SA node
The apex of the heart is situated toward the: back
Left hip
Which chamber experiences a maximum pressure of around 118 mm Hg during contraction?
Left ventricle
64) Which wave on the electrocardiogram (ECG) corresponds with the ventricular filling phase of the cardiac cycle?
P wave wave
damaged atrioventricular (AV) bundle or atrioventricular (AV) node will primarily affect the length of the:
P-R interval.
damaged right bundle branch will prevent the passage of the action potential to the:
Purkinje fibers in the right ventricle.
Which part of the electrocardiogram (ECG) would most be affected by abnormally slow depolarization of the ventricles?
QRS wave
Which wave on the electrocardiogram (ECG) represents ventricular depolarization?
QRS wave
On an electrocardiogram (ECG), atrial repolarization is obscured by the:
QRS wave.
Which of the following can be used to measure heart rate?
R-R interval
65) What wave on the electrocardiogram (ECG) occurs during the ventricular ejection phase of the cardiac cycle?
T wave
What wave on the electrocardiogram (ECG) occurs during the ventricular ejection phase of the cardiac cycle?
T wave
Heart rate can be determined by measuring the time between two successive R waves on an electrocardiogram (ECG), known as the R-R interval.
TRUE
Pressure in the aorta is greater than pressure in the pulmonary trunk; therefore, the left ventricle has to generate a greater pressure than the right ventricle in order to eject blood from the heart.
TRUE
The cardiac conduction system is normally regulated by a population of pacemaker cells known as the sinoatrial (SA) node.
TRUE
The sympathetic nervous system increases cardiac output by increasing both heart rate and stroke volume.,
TRUE
Learning Predict the position of the valves during the ventricular ejection phase.
The AV valves are shut while both semilunar valves are forced open.
Discuss the five waves seen on an electrocardiogram (ECG) and explain what they represent.
The five waves seen on an represents the depolarization of all cells in the electrocardiogram (ECG) are the P deflection. The QRS wave is the first downward wave represents ventricular atria except for the wave, QRS wave, and deflection, and the S wave is the waves. The Q the T wave. The P wave deflection, complex and represents ventricular repolarization. following downward deflection. Learning Outcome: 17.3.5 Bloom's Taxonomy: 3-4) The T wave is normally an upward The T wave follows the S wave of the QRS the R wave is the large upward depolarization and is actually three separate sinoatrial (SA) node and is normally an upward deflection. Applying/Analyzing
Determine the effects to blood flow if a heart attack has caused damage to the left side of the heart
The left side of the heart, often called the systemic pump, receives oxygenated blood from the pulmonary veins and pumps it into the blood vessels that serve the rest of the body, collectively called the systemic circuit. In the systemic circuit, arteries deliver oxygenated blood to the smallest blood vessels, the systemic capillaries. Here gas exchange occurs: Oxygen diffuses from the blood into the tissues, and carbon dioxide diffuses from the tissues into the blood. If the left side of the heart has been damaged, delivery of oxygenated blood to the body's cells and tissues may be impaired.
Explain the significance of the plateau period during the action potential of a cardiac contractile cell.
The plateau period of contractile cell action potential slows the heart rate, allows the heart to fill with blood, increases the strength of the heart's contraction, and prevents tetany by lengthening the heart's refractory period. The prevention of tetany allows the heart to relax and the ventricles to refill with blood before the cardiac muscle cells are stimulated to contract again
Discuss the chronotropic effects of the sympathetic and parasympathetic nervous systems on the heart.
The sympathetic nervous system releases a neurotransmitter, norepinephrine, which has a positive chronotropic effect on the heart. Due to the influence of the sympathetic nervous system, the sinoatrial (SA) node fires more quickly and the calcium ion concentration in the cardiac muscle cells increases. Both effects increase stroke volume, heart rate, and cardiac output. The parasympathetic nervous system releases a neurotransmitter, acetylcholine, from the vagus nerves (CN X). Acetylcholine has a negative chronotropic effect on the heart by slowing the rate of the sinoatrial (SA) node. Thus, heart rate and cardiac output decreases.
What activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)?
The ventricular cells are undergoing action potentials.
Answer: This murmur caused heart sound. Determine a potential cause of his heart murmur. patient learns he has a heart murmur.
This patient probably has a heart murmur caused by a defective valve. Since his physicain hears abnormal sounds during the timing of SI heart sound his defective valve is either the tricuspid vavle or the mitral biscuspid valve. The S1 sound, or "lub" is heard when the atroventricular vables tricuspid and mitral vavles close
Stroke volume (SV) can be calculated by subtracting the end-diastolic volume (EDV) from the end-ystoic volume (ESV),
True
The left side of the heart is often called the systemic pump due to blood flow to the body.
True
The left ventricle has greater muscle mass than the right ventricle greater resistance.
True
The left ventricle has greater muscle mass than the right ventricle since it pumps against greater resistance.
True
Which of the following is a chronotropic agent that decreases heart rate?
acetylcholine
long length of the cardiac action potential, at 200-300 msec, allows for:
an opportunity for the heart to fill with blood
Taxonomy: Outcome: What vessel delivers oxygenated blood to systemic capillaries for gas exchange?
aorta
Where should the left ventricle send blood?
aorta
Which vessel supplies the systemic circuit with oxygenated blood?
aorta
11) The right and left coronary arteries receive blood from the
aorta.
The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the
atria.
Which hormone decreases cardiac output by decreasing blood volume and preload?
atrial natriuretic peptide (ANP)
hormone decreases cardiac output by decreasing blood volume and preload?
atrial natriuretic peptide (ANP)
44) What is NOT part of the cardiac conduction system?
atrioventricular (AV) valve
21) Which valve is situated between the left atrium and left ventricle?
bicuspid (mitral) valve
The coronary sinus does NOT receive blood from the:
brachiocephalic vein.
ds The coronary sinus does NOT receive blood from the: brachiocephalic cardiac
brachiocephalic vein.
wllh W How do cardiac cells sustain a membrane potential of around 0 mV during the plateau phase?
calcium channels remain open
Which of the following volumes should be the greatest
cardiac output (CO)
Which of the following volumes should be the greatest?
cardiac output (CO)
Autorhythmicity in the heart is the responsibility of.
cardiac pacemaker cells.
Autorhythmicity in the heart is the responsibility of:
cardiac pacemaker cells.
Inotropic agents affect:
contractility.
13) Generally, coronary veins empty into a vessel known as the: asilggue
coronary sinus.
right side of the heart receives:
deoxygenated blood from the systemic circuit.
What largely determines preload?
end-diastolic volume (EDV)
Predict the effect on the length of the R-R interval of an electrocardiogram (ECG) if a patient experiences bradycardia.
experiences The R-R interval is the time between two successive duration of the generation and spread of an actionsice R waves on the electrocardiogram This interval represents the entire successive R waves will increase Bloom's Taxonomy: 5-6) Evaluating/Creating as the heart rate slows due to bradycardia. o vion heart rate slower than 60 beats per minute. The length between potential through the heart, and can be measured to determine the heart rate.
7) What is the most superficial layer of the pericardial sac?
fibrous pericardium
32) The rapid influx of calcium ions into pacemaker cells creates a positive membrane potential inside the cell and is responsible for the:
full depolarization phase.
The volume of blood pumped by each ventricle in one heartbeat is known as:
heart rate (HR).
31) What ion movement changes the membrane potential in a contractile cell from negative to
influx of sodium ions
What characteristic differentiates cardiac muscle cells from skeletal muscle cells?
intercalated discs
As ventricular systole begins, all four heart valves are closed during the:
isovolumetric contraction
When is the S2 heart sound heard?
isovolumetric relaxation phase
Describe the Frank-Starling law.
law. Answer: According to the Frank-Starling law, the more the ventricular muscle cells are os! stretched, the more forcefully they contract. The relationship between contraction and stroke volume ensures that the volume of blood discharged from the heart is equal to the volume that enters dlat Bloom's Applying/Analyzing
An insufficient mitral valve (bicuspid valve, or left atrioventricular valve) would allow the
left atrium
An insufficient mitral valve (bicuspid valve, or left atrioventricular valve) would allow the backflow of blood into the:
left atrium.
Which opening in the interatrial septum of the fetal heart connects the right and left atrium?
ligamentum arteriosum
5) The pulmonary circuit involves blood flow from the heart to the:
lungs.
What muscles, present in the ventricles, anchor the atrioventricular valves by tendon-like chords called chordae tendineae?
papillary muscles
Which of the following is NOT a population of pacemaker cells in the heart?
papillary muscles
What is found between the visceral pericardium and the parietal pericardium?
pericardial fluid
fluid pericardium The visceral pericardium is the same as the:
pericardium
During what phase of the action potential will calcium ions enter the contractile cell as potassium ions exit?
plateau phase
What do pacemaker cell action potentials lack?
plateau phase
contractile cell with a sustained membrane potential of 0 mV is experiencing the
plateau phase
73) The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called:
preload.
15) What is the function of the valves in the heart?
prevent backflow of blood through the heart
What vessel delivers oxygenated blood to systemic capillaries for gas exchange?
pulmonary
Which vessel is guarded by a semilunar valve at its base?
pulmonary trunk
Which of the following does NOT return blood to the right atrium of the heart?
pulmonary vein
Which of the following vessels carries oxygenated blood?
pulmonary vein
What vessel(s) deliver oxygenated blood to the left atrium?
pulmonary veins
An insufficient mitral valve (bicuspid valve, or left atrioventricular valve) would allow the backflow of blood into the: ll Blood in the right ventricle arrived from the:
right atrium.
Blood in the right ventricle arrived from the:
right atrium.
What normally serves as the pacemaker of the entire heart?
sinoatrial (SA) node
Which of the following pacemaker cell populations has the fastest intrinsic rate of depolarization at about 60-70 times or more per minute?
sinoatrial (SA) node
The right and left atria depolarize and contract following the arrival of the action potential from the
sinoatrial (SA) node.
What two values are needed in order to calculate cardiac output (CO) for a ventricle?
stroke volume (SV) and heart rate (HR)
Archie has a resting heart rate of 125 beats per minute. Classify his cardiac dysrhythmia.
tachycardia
As a result of the long refractory period in the contractile cell, cardiac muscle can NOT
tetany
Which two arteries arise from the right coronary artery?
the C) the the right marginal artery and the right posterior interventricular artery
64) Which wave on the electrocardiogram (ECG) corresponds with the ventricular filling phase of the cardiac cycle?
the P wave
Afterload is described as:
the force the ventricles must overcome to eject blood into their respective arteries.
Taxonomy: Remembering/Understanding sd Learning Outcome: What valve prevents the backflow of blood from the right ventricle into the right atrium? tricuspid valve
tricuspid valve
What valve prevents the backflow of blood from the right ventricle into the right atrium?
tricuspid valve
Which cranial nerves have a negative chronotropic effect on heart rate?
vagus nerves (CN X)
Which valve is situated between the left atrium and left ventricle?
valve bicuspid (mitral)
Determine the impact if the connection between the sinoatrial (SA) node and the atrioventricular (AV) node becomes blocked.
ventricles will contract more slowly.
During what phase does blood flow from the ventricles into the pulmonary trunk and aorta?
ventricular ejection phase
What produces the "lub dub" heart sounds?
vibrations of the ventricular and blood vessel walls when valves shut
