Chapter 19 (Heart)
The long plateau phase of the cardiac muscle action potential is due to...
Calcium channels remaining open
Pacemaker cells in the SA node...
Can spontaneously depolarize
Most of the middle layer in the heart wall is composed of...
Cardiac muscle cells
The coronary sinus drains the _________ into the ________.
Cardiac veins; right atrium
The first heart sound ("lubb") is associated with...
Closing of the atrioventricular valves
The function of an atrium is to...
Collect blood then pump it to the ventricle
The first blood vessels to branch from the aorta are the ________ arteries.
Coronary
Identify the structure labeled "6"
Cusp of tricuspid valve
In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the...
Mediastinum
When the semilunar valves close, the AV valves then...
Open
Depolarization of the atria corresponds to the EKG's.
P wave
Identify the structure(s) labeled "8".
Papillary muscles
Each of the following factors will increase cardiac output EXCEPT increased
Parasympathetic stimulation
What occurs at the circled labeled "5" on the graph?
Peak systolic pressure
Excess fluid in the ________ causes cardiac tamponade.
Pericardial cavity
The __________ circuit carries blood to and from the lungs.
Pulmonary
Identify the structure labeled "19".
Pulmonary semilunar valve
Blood leaves the right ventricle by passing through the...
Pulmonary valve
Depolarization of the ventricles is represented on an electrocardiogram by the...
QRS complex
The right ventricle pumps blood to the...
Right and left lungs
Blood returning to the heart from the systemic circuit first enters the...
Right atrium
Coronary veins empty into the...
Right atrium
The pulmonary semilunar valve prevents backward flow into the...
Right ventricle
What occurs at the area labeled "B" on the graph?
Semilunar valve closes
What occurs at "A" on the graph?
Semilunar valve opens
"An increase in end-diastolic volume increases the stroke volume" is a way of stating __________ law of the heart.
Starling's
The volume of blood ejected from each ventricle during a contraction is called the...
Stroke volume
What volume is labeled "E" on the graph?
Stroke volume
Cardiac output is increased by...
Sympathetic stimulation
The ________ circuit carries blood from the aorta to the right ventricle.
Systemic
The contraction phase of the cardiac cycle is called...
Systole
As a result of the long refractory period in the cardiac action potential, cardiac muscle CANNOT exhibit...
Tetany
Blood is supplied to the myocardium by...
The coronary arteries
Tetanic muscle contractions don't occur in a normal cardiac muscle because... a) The refractory period lasts until the muscle relaxes. b) Potassium channels outnumber sodium channels c) Neural stimulation is lacking d) Cardiac muscle tissue contracts on its own e) The refractory period ends before the muscle reaches peak tension
The refractory period lasts until the muscle relaxes
The normal pacemaker of the heart is located in...
The sinoatrial node
Blood flowing into the heart from the venae cavae flows next through the _______ valve.
Tricuspid
The T wave on an ECG tracing represents...
Ventricular repolarization
Which chamber receives oxygenated blood from the pulmonary circuit?
16
An increase in the rate of action potentials from baroreceptors will trigger a reflex to...
Both decrease heart rate and decrease pressure
The heart is innervated by _______ nerves.
Both parasympathetic and sympathetic
During the T wave of the electrocardiogram, the ventricles are...
Both repolarizing and relaxing
_________ is to slow heart rate as ___________ tachycardia is to fast heart rate.
Bradycardia; tachycardia
At a heart rate of 60 beats/minute, a cardiac cycle lasts
1 second
The systolic part (both atrial and ventricular) of a cardiac cycle lasts, on average,
370 msec
There are _______ pulmonary veins.
4
The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. Bundle branches The sequence in which excitation would move through this system is...
4, 3, 2, 5, 1
The following is a list of vessels and structures that are associated with the heart. What is the correct order for the flow of blood entering from the systemic circulation? 1. Right atrium 2. Left atrium 3. Right ventricle 4. Left ventricle 5. Venae cavae 6. Aorta 7. Pulmonary trunk 8. Pulmonary veins
5, 1, 3, 7, 8, 2, 4, 6
The heart pumps approximately _________ liters of blood each day.
8,000
Pacemaker cells isolated from the SA node generate action potentials at _________ beats per minute.
80-100
A patient has an end-diastolic volume of 125 ml. A heart attack has weakened her left ventricle so it can pump a stroke volume of only 40 ml. Calculate her end-systolic volume.
85 ml
The adult heart is roughly the size of...
A man's clenched fist
What occurs at the area labeled "C" on the graph?
AV valve closes
What occurs at the area labeled "D" on the graph?
AV valve opens and filling of ventricles begins
The first heart sound is heard when the...
AV valves close
A heart murmur might be caused by... a) mitral valve b) swirling of blood in the ventricle c) pulmonic valve insufficiency d) all of the answers are correct e) aortic valve insufficiency
All of the answers are correct
Drugs known as calcium channel blockers such as nifedipine can be used to... a) dilate the coronary arteries b) decrease the force of cardiac contraction c) produce a negative inotropic effort d) decrease blood pressure e) all of the answers are correct
All of the answers are correct
Intercalated discs serve to transfer ________ from cell to cell. a) All of the answers are correct b) Ionic currents c) Electrical signals d) Action potentials e) The force of contraction
All of the answers are correct
End-systolic volume is defined as the...
Amount of blood remaining in a ventricle after contraction
The left ventricle pumps blood to the...
Aorta
The earlike extension of the atrium is the...
Auricle
The superior portion of the heart where major blood vessels enter and exit is the...
Base
With each ventricular systole...
Blood pressure increases
The relaxation phase of the cardiac cycle is called...
Diastole
Artery is to __________ as vein is to _________. a) toward; away b) afferent; away c) efferent; away d) efferent; afferent e) afferent; efferent
Efferent; afferent
The __________ is the volume of blood in a ventricle at the beginning of systole.
End-diastole volume
What volume is labeled "F" on the graph?
End-diastolic volume
What volume is labeled "G" on the graph?
End-systolic volume
The __________ lines the chambers of the heart, covers the heart valves, and is continuous with the endothelium.
Endocardium
The visceral pericardium is the same as the...
Epicardium
What occurs at the circles labeled "4" on the graph?
Isovolumetric ventricular contraction
What occurs at the circled labeled "7" on the graph?
Isovolumetric ventricular relaxation
Blood returning to the heart from the pulmonary circuit first enters the....
Left atrium
What is occurring in the left atrium at the circle labeled "2" on the graph?
Left atrium is in systole
Blood is supplied to the muscular wall of the left atrium by the...
Left coronary artery
Identify the structure labeled "21".
Ligamentum arteriosum
