Cardiovascular System - The Heart (Chapter 18)
The base of the heart is located at the bottom of the heart. (True or False)
False, The base is located at the top of the heart.
Refers to the property of cardiac muscle depolarizing and contracting as a unit.
Functional syncytium
The _____ cardiac vein runs with the anterior interventricular artery.
Great
The cardiovascular system consists of a pump called the ______ and tubes called ________ ________.
Heart, Blood vessels
The ____ ____ artery subdivides into a circumflex artery and a(n) ______ interventricular artery.
Left Coronary, Anterior
Which heart chamber receives blood from the pulmonary veins?
Left atrium
What is the most muscular chamber of the heart?
Left ventricle
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
Left ventricle
Contraction of what muscle helps keep the atrioventicular valves closed?
Papillary
What muscle allows the atria to be more distensible with thinner walls while still capable of increasing pressure during contraction?
Pectinate
Name the ridged bundles of muscle found projecting inside the right atrium.
Pectinate muscles
Serous fluid is secreted in the _______ cavity by the parietal and visceral pericardium.
Pericardial
Inflammation of the membranes surrounding the heart.
Pericarditis
The fibrous ______ is a connective tissue membrane surrounding the heart that anchors the heart in the thoracic cavity.
Pericardium
What is the function of the coronary circulation?
Provide a blood supply to the heart
The ________ circulation transports blood to the lungs for oxygenation and CO2 removal.
Pulmonary
The left atrium receives blood from the lungs through the:
Pulmonary Veins
The right ventricle pumps blood out to the lungs through the ______ ________ which divides into a right and left ______ _______.
Pulmonary trunk, Pulmonary artery
What is the name of the right semilunar valve?
Pulmonary valve
What valve prevents blood flow from the pulmonary trunk to the right ventricle?
Pulmonary valve
Blood returns from the pulmonary circulation through the ______ veins to the _____ Atrium.
Pulmonary, Left
Muscle bundles in the ventricles which increase contraction force without making the wall enormously thick.
Trabeculae carneae
Name the irregular ridges of muscle lining the ventricles.
Trabeculae carneae
What is the name of the right atrioventricualr (AV) valve?
Tricuspid valve
What valve prevents blood flow from the right ventricle to the right atrium?
Tricuspid valve
What regulatory protein blocks myosin binding sites?
Tropomyosin
What regulatory protein binds calcium to change shape and shift another regulatory protein to uncover myosin bind sites?
Troponin
Blood on the right never mixes with blood on the left, once the heart is fully developed (True or False)
True
The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human. (True or False)
True
The heart is actually (one, two, or three) pumps?
Two
The vessels that transport blood to the heart.
Veins
The right atrium receives blood from the superior and inferior ______ ______ , and the _______ sinus.
Vena cava, Coronary
Blood returns from the systemic circulation through the ____ ____ to the ____ atrium
Vena cava, Right
The chambers that pump blood to the arterial system.
Ventricles
What is happening during the "pause" phase when the heart is resting (relaxing)?
Ventricles are filling.
What causes the abnormal swishing or whooshing sound that is heard as blood regurgitates back into an atrium from its associated ventricle?
blood turbulence
What carries oxygen-poor venous blood of the coronary circulation into the right atrium?
coronary sinus
Name the inner lining of the heart
endocardium
The structure that prevents backflow of blood into the left atrium
Mitral (bicuspid) valve
What layer of the heart is the epicardium?
Outermost layer
Which chamber of the heart exits into the pulmonary trunk?
right ventricle
What carries oxygen-poor venous blood from above the diaphragm from areas of the upper body and extremities into the right atrium?
superior vena cava
Identify the right atrioventricular valve.
tricuspid valve
The moderator band is found on both the right and left side of the heart. (True or False)
False
Blood flow through the heart (study)
All systemic veins return oxygen-poor venous flow to the right atrium, through the tricuspid to the right ventricle, and up and out the pulmonary semilunar valve to the pulmonary trunk and pulmonary arteries to the capillaries of the lungs. Returning oxygen-rich blood flowing through pulmonary veins enters the left atrium, passes through the mitral valve to the left ventricle, and flows out through the aortic semilunar valve into the aorta and on to systemic capillaries.
The ____ cardiac vein generally drains directly into the right atrium.
Anterior
The left ventricle pumps blood to the body through the:
Aorta
The structure that is located anatomically between the aorta and the left ventricle.
Aortic semilunar valve
What is the name of the left semilunar valve?
Aortic valve
What valve prevents blood flow from the aorta to the left ventricle?
Aortic valve
The thicker walled chambers near the _____ of the heart are the right and left ventricle.
Apex
The thinner walled chambers near the ______ of the heart are the right and left atria.
Base
What is the valve found between the left atrium and left ventricle?
Bicuspid (mitral) Valve
The coupling agent between excitation and contraction is the release of _______ ions triggered by an action potential.
Calcium
A dangerous condition in which blood or other fluids accumulate around the heart to limit its pumping ability.
Cardiac Tamponade
What fibrous structure functions to anchor the atrioventricular valves in a closed position?
Chordae tendineae
The ________ artery follows the along the coronary sulcus on the left side of the heart.
Circumflex
What is the inner heart surface and is composed of simple squamous epithelium?
Endocardium
What is another name for the visceral pericardium?
Epicardium
Oxygenated blood flows through the right side of the heart. (True or False)
False
Cardiac muscle cannot exhibit tetanic contractions because of a long _________ ___________.
Refractory period
What kind of membrane is the epicardium?
Serous
The presence of alternate dark and light stripes allows for the ______ ________ _________ of muscle contraction .
Sliding filament mechanism
The _____ cardiac vein runs with the marginal artery.
Small
The vessel that carries oxygen-rich blood to tissues
aorta
What carries oxygen-poor venous blood from below the diaphragm from the areas of the lower body and extremities into the right atrium?
inferior vena cava
How does heart rate affect stroke volume?
A high heart rate reduces the end diastolic volume (EDV) and stroke volume (SV), because there is less time for ventricular filling.
Which of these structures conduct(s) action potentials the slowest?
AV Node- Action potentials slow down as they pass through the AV node. This gives the atria time to finish contracting before the ventricles are depolarized.
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
AV Node- Yes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
Brief, large, all-or-none change in membrane potential that occurs in muscle and nerve cells. Regenerative signals that can propagate long distances along the membrane of a cell. Also called impulses or spikes.
Action potential
What is an abnormal heart rhythm called?
Arrhythmia
The vessels that transport blood away from the heart
Arteries
Unlike the systemic circulation, pulmonary _____ carry deoxygenated blood and pulmonary ____ carry oxygenated blood.
Arteries, Veins
The chambers that receive blood from the venous system.
Atria
The P wave of the electrocardiogram begins right before __________.
Atrial systole
The "Lub" of the heart sounds is due to closing of the ______ valves
Atrioventricular
What is the electrical connection between the atria and ventricles?
Atrioventricular bundle
The ____________ ____________, _______________ _____________ and __________ __________ rapidly spread depolarization from the atrioventricular node to the thick ventricular myocardium.
Atrioventricular bundle, Bundle branches, Purkinje fibers
Identify the ear like flaps that are attached to the top chambers of the h
Auricle
What is a slower resting heart rate than normal called?
Bradycardia
The plateau phase during the action potential is due to the influx of _____ ions during repolarization
Calcium
The plateau phase during the action potential is due to the influx of ______ ions during repolarization.
Calcium
Depolarization during SA node and AV node action potentials is due to the influx of what?
Calcium ions
the sequence of events that occurs during one heartbeat.
Cardiac cycle
In contrast to a skeletal muscle cell action potential, why does the action potential for a cardiac muscle cell contain a "plateau" phase?
Cardiac muscle cells contain slow Ca2+Ca2+ channels in their sarcolemma that continue to allow influx of Ca2+Ca2+ ions after Na+Na+ channels are inactivated.- Fast voltage-gated Na+Na+ channels are open only for a very brief time before they are inactivated, but the resulting depolarization opens slow Ca2+Ca2+ channels that start a positive feedback cycle that temporarily keeps the membrane potential high.
What circulation provides blood flow to the heart muscle?
Coronary
A procedure to unblock fatty plaques and enlarge the coronary arteries.
Coronary angioplasty
A procedure to use veins to bypass blockage sites on the coronary arteries.
Coronary bypass
Most cardiac veins drain into a sac-like structure on the posterior surface of the heart called the _____ ______.
Coronary sinus
During a muscle contraction, the sarcomere shortens due to what?
Cross bridge cycling
Change in membrane potential such that the cell interior becomes less negative (more positive). Characteristic of the initial phase of an action potential.
Depolarization
During a resting heart rate, ________ lasts about twice as long as _______
Diastole, Systole
The measurement of electrical activity of the heart.
Electrocardiogram
the volume of blood in the ventricles before ventricular contraction.
End diastolic volume
the volume of blood in the ventricles after ventricular contraction.
End systolic volume
What is a random and uncoordinated activation of the heart called?
Fibrillation
What physically and electrically separates the atria from the ventricles and serves as the attachment site for the valves of the heart?
Fibrous endoskeleton
An abnormal heart sound can occur if blood flows between the atria through an opening in the _____ _______ or an atrial septal defect.
Fossa ovalis
What is the remnant of the hole between the right and left atria?
Fossa ovalis
What is a disruption of the conduction between the atria and the ventricles?
Heart block
A ______ ______ refers to an abnormal heart sound from abnormal blood flow in the heart.
Heart murmur
What is the effect of high blood pressure on cardiac output?
High blood pressure increases afterload and reduces cardiac output (CO).
Why does a graph of the membrane potential of living pacemaker cells never demonstrate a flat line?
Hyperpolarization of pacemaker cells triggers the opening of slow Na+ channels and starts a new slow depolarization phase.- At the end of an action potential, as repolarization and hyperpolarization occur, slow Na+ channels open, causing the membrane potential to immediately start to increase again (called the pacemaker potential), eventually triggering another action potential.
Cardiac muscle structures that physically and electrically connect cells.
Intercalated discs
What is the muscular partition that separates the right ventricle from the left ventricle?
Interventricular septum
The volume of blood with the ventricles remains constant during:
Isovolumetric contraction and Isovolumetric relaxation
The ventricular pressure rapidly decreases during ___________ ____________
Isovolumetric relaxation
The _____ ventricle pumps blood out the _____ to the tissues.
Left, Aorta
The systemic circulation occurs between the _____ ventricle and the ______ atrium.
Left, Right
The ____ cardiac vein runs with the posterior interventricular artery.
Middle
What is the name of the left atrioventricular (AV) valve?
Mitral valve
What valve prevents blood flow from the left ventricle to the left atrium?
Mitral valve
What is the middle layer of the heart and is composed primarily of cardiac muscle?
Myocardium
Activation of skeletal muscle requires the ____________ _______________while cardiac muscle is activated by __________ __________ of the specialized cardiac muscle.
Neuromuscular junction, Pacemaker cells
The __ wave of the ECG precedes active filling of the ventricles.
P
The _ _____ of the ECG represents atrial depolarization.
P wave
Contraction of the atria results from which wave of depolarization on the ECG tracing?
P wave- Yes, the P wave represents atrial depolarization, which leads to atrial contraction.
The __ _____ of the ECG represents conduction between the SA node and the ventricles.
PR interval
Repolarization of the action potential in contractile myocardium and Purkinje fibers is due to the outflow of ______ ions.
Potassium
Diastolic depolarization during the pacemaker potential is due ______ ______ channels closing and ______ _______ channel opening.
Potassium ion, Sodium ion
Repolarization during action potentials of the SA node and AV node is due to the outflow of what?
Potassium ions
Identfiy the valve located at the exit of the right ventricle.
Pulmonary semilunar valve
What directly depolarize the contractile myocardium of the ventricles nearly simultaneously?
Purkinje fibers
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.- Action potentials normally originate in the SA node because the pacemaker cells there depolarize faster than pacemaker cells located elsewhere in the heart. However, certain drugs, such as caffeine, nicotine, or cocaine, can stimulate other pacemaker cells to speed up and temporarily "escape" the SA node rhythm. If this ectopic focus consists of Purkinje fibers, then ventricular contraction will occur prematurely, prior to ventricular filling. Without proper filling, this abnormal contraction pumps little blood and is not sensed. However, the following normal beat generated from the SA node has augmented filling and is sensed, resulting in the missed beat sensation.
The ___ ______ of the ECG precedes isovolumetric contraction
QRS complex
The ___ ______ of the ECG represents ventricular depolarization.
QRS complex
The __ ______ of the ECG represents the duration of a ventricular action potential.
QT interval
The ____ ____ artery subdivides into a marginal artery and a(n) _____ interventricular artery.
Right Coronary, Posterior
Which chamber receives blood from the superior and inferior vena cavae?
Right atrium
The _______ ________artery follows the along the coronary sulcus on the right side of the heart.
Right coronary
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
Right ventricle
The pulmonary circulation occurs between the ________ ventricle and the ______ atrium.
Right, Left
The _____ ventricle pumps blood out the __________ ____ to the lungs.
Right, Pulmonary Trunk
Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat?
SA Node- Like the rest of the intrinsic conduction system, the SA node contains pacemaker cells that spontaneously depolarize. The cells within the SA node, however, depolarize faster than the other cells within the system. This causes action potentials to initiate in the SA node rather than in any of the other structures.
What structure in the intrinsic cardiac conduction system determines heart rate?
SA Node- The SA node is composed of pacemaker cells that initiate and set the initial pace, or the sinus rhythm, of the heartbeat.
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
SA Node- Yes, the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart.
Depression of the __ _______ of the ECG may indicate ischemic heart disease.
ST segment
During a muscle contraction, the ________ shortens due to Cross bridge cycling.
Sarcomere
What releases calcium to trigger muscle contraction?
Sarcoplasmic reticulum
What removes calcium to initiate muscle relaxation?
Sarcoplasmic reticulum
The "Dub" of the heart sounds is due to closing of the _______ valves.
Semilunar
An abnormal heart sound can occur if blood flows backwards from the pulmonary trunk or aorta through inverted or leaky ______ valves or from the ventricles to the atria through prolapsed or leaky ______ valves
Semilunar, Atrioventricular
What is the primary pacemaker of the heart?
Sinoatrial node
Both the ________ _________ (primary pacemaker) and the _______ ________ (secondary pacemaker) exhibit diastolic depolarization, a spontaneous depolarization referred to as a pacemaker potential.
Sinoatrial node, Atrioventricular node
Both cardiac muscle and skeletal muscle contain stripes called:
Striations
The difference between the end diastolic volume and the end systolic volume
Stroke volume
The _________ circulation transports blood to provide O2 and nutrients to the tissues.
Systemic
The capillaries receiving blood flow from the left side of the heart.
Systemic capillaries
The ventricle is in _________ between the first and second heart sounds.
Systole
The __ wave of the ECG precedes isovolumetric relaxation.
T
The _ ____ of the ECG represents ventricular repolarization.
T wave
What is a faster resting heart rate than normal called?
Tachycardia
What is the role of the atrioventricular bundle?
The atrioventricular bundle provides the only pathway for electrical signals to pass from the atria to the ventricles- The atrial cardiac cells are not connected by gap junctions to the ventricular cardiac cells. The only means by which the electrical signals of the heart can pass from atria to ventricles is the atrioventricular bundle.
What are the valve positions during isovolumetric contraction?
The atrioventricular valves and semilunar valves are both closed.
nervous system's role in regulating heart rate?
The parasympathetic division normally inhibits the heart, keeping it beating at a slower rate than it would be on its own.
The volume of blood in the ventricles increases during ______ filling
Ventricular
During the cardiac cycle, which phase comes after isovolumetric contraction?
Ventricular ejection
The volume of blood decreases during ______ ______.
Ventricular ejection
Where are the two Bundle branches are found?
along the interventricular septum
What is the secondary pacemaker of the heart?
atrioventricular node
formula for cardiac output
cardiac output = stroke volume x heart rate
The beginning of the QRS complex of the electrocardiogram (ECG) immediately precedes which of the following events?
closing of atrioventricular valves
Which of the following can be heard with a stethoscope most easily?
closing of atrioventricular valves
An increase in sympathetic stimulation of the heart would increase stroke volume by increasing __________.
contractility
relaxation of the atria and ventricles
diastole
At a resting heart rate, about 80% of ventricular filling occurs during Atrial _____ and 20% occurs during Atrial _____
diastole, systole
What does the ECG wave tracing represent?
electrical activity in the heart- Yes, the ECG waves show the depolarization and repolarization in various areas of the heart.
an effect of epinephrine, norepinephrine, and thyroxine?
increase contractability
What heart chamber pushes blood through the aortic semilunar valve?
left ventricle
The ____ ventricle is much thicker than the _____ ventricle and develops the greatest pressure.
left, right
As part of a blood drive on campus for the American Red Cross, you and your friends have just donated 500 mlml 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 mlml 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
During resting conditions, the majority of ventricular filling is caused by _________.
passive blood flow from atrium
What is the ligamentum arteriosum?
remnant of ductus arteriosus
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- Beginning contraction at the apex causes blood to be forced upward, through the semilunar valves, and into the aorta and pulmonary trunk. This makes ventricular ejection more efficient, much like squeezing a tube of toothpaste up from the bottom is more efficient at dispensing the toothpaste than is squeezing from the top.
contraction of the atria and ventricles
systole
The heart sounds associated with the atrioventricular valves closing occur at __________.
the start of ventricular systole
What does the QRS complex represent in the ECG wave tracing?
ventricular depolarization- Yes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.
