Ch 18 The Cardiovascular System: The Heart HW

1. ________: Delay(s) occurs here while atria contract 2. ________: Set(s) the pace for the entire heart 3. ________: Link(s) between the SA node and AV node 4. ________ : Electrical link(s) between atria and ventricles 5. ________: Convey(s) the impulse throughout the ventricular walls 6. ________: Convey(s) the impulse down the interventricular septum

1. AV node 2. SA node 3. Internodal pathways 4. AV bundle 5. Purkinje fibers 6. Bundle branches

Calculate the stroke volume if the end diastolic volume (EDV) is 135 mL/beat and the end systolic volume (ESV) is 60 mL/beat.

75 mL/beat The SV is calculated by subtracting the ESV from the EDV. You are comparing the volume of the ventricle at its fullest to its emptiest.

Calculate the cardiac output if heart rate (HR) is 90 beats per minute, stroke volume (SV) is 110 ml/beat, end diastolic volume (EDV) is 140 ml, and end systolic volume (ESV) is 30 ml.

9.9 L/min

What is the ligamentum arteriosum?

A remnant of the ductus arteriosus; The ligamentum arteriosum is a remnant of the ductus arteriosus. The ductus arteriosus is a fetal shunt that connects the pulmonary trunk to the aorta.

Which of these structures conduct(s) action potentials the slowest?

AV node

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?

AV node

Increased pressure in the ventricles would close what valve(s)?

AV valves only

Name the inner lining of the heart.

Endocardium; The endocardium is the smooth, slick lining of the chambers of the heart.. Both endocardium and endothelium are composed of simple squamous epithelial tissue, which minimizes friction between the wall of the chamber/vessel and the blood.

Which of the following would increase cardiac output?

Epinephrine

The base of the heart is located at the bottom of the heart.

False

The moderator band is found on both the right and left side of the heart.

False

Oxygenated blood flows through the right side of the heart.

False Oxygenated blood returning from the lungs is received by the left atrium, then to the left ventricle before being pumped out to the body. This pathway of blood flow is known as the systemic circulation.

What heart chamber pushes blood through the aortic semilunar valve?

Left ventricle The aortic valve is located between the left ventricle and the aorta. The left ventricle pumps oxygenated blood out of the heart through the aortic valve to the body.

decreases heart rate

Lying down Digesting a meal

Oxygen rich items

left atrium left ventricle pulomanry veins aorta

Identify the most muscular chamber.

left ventricle; The left ventricle is responsible for pumping blood out to the body. This requires a lot of force. The left ventricle is the most muscular in order to pump the blood with adequate force

Drag and drop the terms to arrange them, from left to right, in order of blood flow of oxygen-rich blood into the heart.

lungs => lung capillaries => pulmonary veins => left atrium => mitral/biscuspid valve => left ventricle => aortic/semilunar valve

Which of the following is correct about the filling of the ventricles?

Most blood flows passively into the ventricles through open AV valves.

Which statement regarding cardiac muscle structure is accurate? A. Cardiac muscle cells are independent of one another both structurally and functionally. B. Cardiac cells are long, cylindrical, and multinucleate. C. Cardiac cells possess fewer mitochondria than other types of muscle cells. D. Myofibrils of cardiac muscle tissue vary in diameter and branch extensively.

Myofibrils of cardiac muscle tissue vary in diameter and branch extensively.

Contraction of the atria results from which wave of depolarization on the ECG tracing?

P wave

Name the ridged bundles of muscle found projecting inside the right atrium.

Pectinate muscles

One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion?

Potassium

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

Pressure in the atria would be greater than the pressure in the ventricles.

What is the function of the coronary circulation?

Provide a blood supply to the heart; Correct. The coronary circulation provides oxygenated blood to the heart through coronary arteries. Coronary veins return the deoxygenated from the heart to the coronary sinus on the posterior surface of the heart. The coronary sinus empties the deoxygenated blood directly into the right atrium where it joins deoxygenated from the body.

Your patient has been diagnosed with right ventricular failure. Which of the following abnormalities is not a direct result of this problem?

Pulmonary edema (fluid in the alveoli)

Identfiy the valve located at the exit of the right ventricle.

Pulmonary semilunar valve

A person notices his or her heart beat because he or she senses blood being pumped by the heart. Excessive caffeine intake can lead to irregular heart rhythms (arrhythmias) that patients perceive as "skipped beats." Given that caffeine is a stimulant, which of the following mechanisms best explains the reason for the feeling that the heart skipped a beat?

Purkinje fibers initiate spontaneous action potentials, which cause the ventricles to contract early.

Oxygen-poor items

Right atrium Right ventricle Pulmonary arteries Superior vena cava

Which chamber of the heart exits into the pulmonary trunk?

Right ventricle The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.

Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?

SA node

Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat?

SA node

As part of a blood drive on campus for the American Red Cross, you and your friends have just donated 500 ml of blood. You are now relaxing at the student lounge, waiting for A&P lab to begin. Unfortunately, even though you are thirsty, you haven't bothered to buy yourself a drink. Other than a little soreness of the skin and tissue around your median cubital vein, you feel fine. How has your 500 ml decrease in blood volume most likely affected your cardiac output, heart rate, and stroke volume?

no change in cardiac output, increased heart rate, decreased stroke volume

Drag and drop valve names to their correct location in the image.

Tricuspid valve pulmonary semilunar valve aortic semilunar valve mitral (bicuspid) valve

The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human.

True

Blood on the right never mixes with blood on the left, once the heart is fully developed.

True DF

The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important?

so blood is forced upward, toward the semilunar valves

The _________ cava carries oxygen-poor venous blood from above the diaphragm from areas of the upper body and extremities into the right atrium.

superior vena

In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells?

the flow of positive ions from adjacent cells

Identify the right atrioventricular valve.

tricuspid valve

What does the QRS complex represent in the ECG wave tracing?

ventricular depolarization

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

ventricular diastole

Select the correct partial path. This path is part of the complete blood flow pathway. You should be able to trace flow starting in any location.

Blood moves from the aorta, through smaller systemic arteries, and into systemic capillaries. From there it moves through systemic veins, into the right atrium, and through the tricuspid valve.

The _________ cava carries oxygen-poor venous blood from below the diaphragm from the areas of the lower body and extremities into the right atrium.

inferior vena

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

isovolumetric contraction, ventricular ejection, isovolumetric relaxation

After you note a murmur in a newborn, the pediatric cardiology consultant diagnoses a patent ductus arteriosus. Why is this a cause for concern?

The higher pressure in the aorta will push extra blood through the ductus arteriosus into the child's pulmonary circulation.

Identify the valve found between the left atrium and left ventricle.

Bicuspid (mitral) valve

Name the irregular ridges of muscle lining the ventricles.

Trabeculae carneae

Which of the following descriptions does not describe atrioventricular (AV) valves?

formed from pocket-like cusps

What causes the aortic semilunar valve to close?

greater pressure in the aorta than in the left ventricle

Arrange these elements of the intrinsic conduction system in the order that a depolarizing impulse travels during a normal heartbeat.

1) SA node 2) Internodal pathways 3) AV node 4) AV bundle 5) Bundle branches 6) Purkinje fibers

1. ________: the number of heart beats per minute 2. ________: the volume of blood in one ventricle before contraction 3. ________: the volume of blood per heart beat pumped out by one ventricle 4. ________: the volume of blood per minute flowing into one atrium 5. ________: the volume of blood per minute pumped out by one ventricle 6. ________: the volume of blood in one ventricle after contraction

1. Heart rate (HR) 2. End diastolic volume (EDV) 3. Stroke volume (SV) 4. Venous return (VR) 5. Cardiac output (CO) 6. End systolic volume (ESV)

1. The prefix ______ means heart or heart action. 2. The prefix ______ means ventricle of the heart. 3. The prefix ______ means atrium. 4. The prefix ______means electricity.

1. cardi- 2. ventriculo- 3. atri- 4. electro-

1. The structure that prevents backflow of blood into the left atrium is the _______________ . 2. The vessel that carries oxygen-rich blood to tissues is the _________ . 3. The capillaries receiving blood flow from the left side of the heart are the _________ . 4. The structure that is located anatomically between the aorta and the left ventricle is the ______ .

1. mitral (biscuspid valve) 2. aorta 3. systemic capillaries 4. aortic semilunar valve

Identify the ear like flaps that are attached to the top chambers of the heart.

Auricle

What fibrous structure functions to anchor the atrioventricular valves in a closed position?

Chordae tendineae Chordae tendineae are the fibrous cords that attach the atrioventricular valves to papillary muscles. They help anchor the atrioventricular valves in a closed position during ventricular contraction.

Which of the following can be heard with a stethoscope most easily?

Closing of atrioventricular valves

Assume that blood is flowing from the coronary sinus to the lung capillaries. Place the anatomical labels in order of flow in the target boxes.

Coronary sinus => Right atirum => Tricuspid valve => Right ventricle => pulmonary semilunar valve => pulmonary trunk => Pulmonary arteries => capillaries of lungs

Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?

Gap junctions Yes, action potentials generated by the autorhythmic cells spread waves of depolarization to contractile cells through gap junctions. If the depolarization causes the contractile cells to reach threshold, they will in turn generate an action potential.

Predict the changes in heart rate, stroke volume, and cardiac output for each of the following conditions by filling out the table below. Drag the appropriate labels to their respective targets.

Increased sympathetic activity: Increase HR, SV, CO Increase Preload: No change in HR, increase SV and CO Increased exercise: Increase HR, SV, CO Increase contractility: No change in HR, increase SV and CO

Which of the following would decrease stroke volume?

Increasing afterload

The beginning of the QRS complex of the electrocardiogram (ECG) immediately precedes which of the following events?

closing of the atrioventricular valves

An increase in sympathetic stimulation of the heart would increase stroke volume by increasing ________ .

contractility

The ________ carries oxygen-poor venous blood of the coronary circulation into the right atrium.

coronary sinus

What does the ECG wave tracing represent?

electrical activity of the heart

When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane?

fast calcium

increases heart rate

fight or anger standing up exercise

Repolarization of an autorhythmic cell is due to the opening of which channels?

voltage-gated potassium channels