A&P II: Chapter 17, 18, & 20 Lecture Exam
Which of the following functions is not associated with the heart?
To increase the rate at which erythrocytes are formed
What is the volume of blood pumped out by one ventricle per heart beat?
stroke volume
Approximately how much blood is pumped from each ventricle during the ventricular ejection phase?
70ml
What percentage of atria blood flows passively into the ventricles?
80%
What is the MAP given a systolic pressure of 130 mm Hg and a diastolic pressure of 70 mm Hg?
90 mm Hg
What is the average value for mean arterial pressure?
95 mm Hg
Which of the following chemical messengers decreases heart rate?
Acetylcholine
Which of the following molecules decreases heart rate, and thus cardiac output and blood pressure?
Acetylcholine
Which of the following hormones does not act to increase blood pressure?
Atrial natriuretic peptide
What allows the atria and ventricles to depolarize and contract separately?
Atrioventricular node delay
Which of the following factors does not contribute to venous blood return?
Contractions of the right ventricle of the heart
Which of the following stimuli is detected by a chemoreceptor?
Decreased blood oxygen concentration
Which of the following factors influences blood volume?
Dehydration
Which of the following factors would increase cardiac output to the greatest extent?
Increased heart rate and increased stroke volume
Which of the following statements best describes the apex of the heart?
Inferior tip of the heart and points toward the left side
During what part of the action potential will calcium ions enter the contractile cell?
Plateau phase
What is a contractile cell with a membrane potential of 0 mV experiencing?
Plateau phase
What is the function of the valves in the heart?
Prevent backflow of blood through the heart
Which of the following blood vessels is not a great blood vessel of the heart?
Pulmonary arteries
Which vessel is guarded by a semilunar valve at its base?
Pulmonary trunk
Which of the following vessels carries oxygenated blood?
Pulmonary vein
Which of the following pacemaker cell populations has the slowest intrinsic rate of depolarization at about 20 times per minute?
Purkinje fiber system
What obscures atrial repolarization on the electrocardiogram?
QRS complex
Which wave on the electrocardiogram represents ventricular depolarization?
QRS complex
Which electrocardiogram finding can be used to measure heart rate?
R-R interval
Inotropic agents affect
Contractility
Calculate the end-systolic volume if the end-diastolic in a resting heart is 110 ml and stroke volume is 70 ml
40 ml
What percentage of the total number of cardiac muscle cells are pacemaker cells?
1%
Stage 2 hypertension results if resting blood pressure is higher than
140/90 mm Hg
Which of the following terms refers to the force the ventricles must overcome to eject blood into their respective arteries?
Afterload
Excessive vasodilation can lead to a condition known as
Anaphylactic shock
Where does the left ventricle send blood?
Aorta
Which of the following events is not part of the cardiac cycle?
Atrial contraction phase
Which hormone decreases cardiac output by decreasing blood volume and preload?
Atrial natriuretic peptide
Which of the following hormones decrease cardiac output by decreasing blood volume and preload?
Atrial natriuretic peptide
What might happen if the papillary muscles and/or chordae tendinae stopped functioning?
Blood would leak back into the atria from the ventricles
What cardiac dysrhythmia does a patient have with a resting heart rate of 50 beats per minute?
Bradycardia
Which of the following ion channels are time-gated closing channels?
Calcium ion channels
Autorhythmicity in the heart is a function of
Cardiac pacemaker cells
What condition results from excess fluid in the pericardial cavity compressing the heart and reducing the capacity of the ventricles to fill the blood?
Cardiac tamponade
What structure attaches the cusps of the atrioventricular valves to the papillary muscles?
Chordae tendinae
Which coronary artery supplies the left atrium and parts of the left ventricle?
Circumflex artery
Which of the following events can be heard most easily with a stethoscope?
Closing of atrioventricular valves
Which of the following structures connects vessels through vascular anastomoses?
Collaterals
Which of the following cell populations does not spontaneously generate action potentials in the cardiac conduction system?
Contractile cells
What provides a graphic representation of all the action potentials occurring in the heart?
Electrocardiogram
What are the three layers of the heart wall from superficial to deep?
Epicardium, myocardium, and endocardium
What is the most superficial layer of the pericardial sac?
Fibrous pericardium
Which opening in the interatrial septum of the fetal heart connects the right and left atrium?
Foramen ovale
Which of the following blood vessels are associated with the coronary sinus?
Great cardiac
What kind of ion channels are unique to pacemaker cells?
HCN Channels
Which of the following structural components is only found in cardiac muscles?
Intercalated discs
Looking in a microscope, what are the visible structures that join cardiac muscle cells?
Intercalcated discs
During what phase is the S1 heart sounds first heard?
Isovolumetric contraction phase
Which of the following statements describes the total refractory period of cardiac muscle?
It is longer than the total refractory period for skeletal muscle
Which f the following is not a risk factor for coronary artery disease or mycardial ischemia?
Low blood pressure
Which of the following arteries has the smallest diameter?
Metarteriole
Which wave on the ECG corresponds with the ventricular filling phase of the cardiac cycle?
P wave
A damaged atrioventricular bundle or AV node will primarily affect the length of the
P-R interval
Which of the following structures is associated with the atria?
Pectinate muscles
Which of the following paths does an action potential in the heart normally take?
SA node atrial contractile cells AV node where it is delayed AV bundle right and left bundle branches Purkinje fibers ventricular contractile cells
The right and left atria depolarize and contract following the arrival of the action potential from the
Sinoatrial node
What normally serves as the pacemaker of the entire heart?
Sinoatrial node
One mechanism that increases the rate venous blood returns to the heart is by
Skeletal muscle pumps
What two valves are needed to calculate cardiac output for a ventricle?
Stroke volume and heart rate
Which blood vessels experience the sharpest decrease in blood pressure?
Systemic arteries
Which blood vessels handle the highest blood pressure?
Systemic arteries
What part of an electrocardiogram represents ventricular repolarization?
T wave
What activity is occurring in the heart during the Q-T interval on an electrocardiogram?
The ventricular cells are undergoing action potentials
Which of the following statements best describes how coronary artery anastomoses might help a patient with coronary heart disease?
They provide alternate routes of blood flow when a vessel is blocked
What valve prevents the back flow of blood from the right ventricle into the right atrium?
Tricuspid valve
Blood in the right atrium should travel next past the
Tricuspid valve and into the right ventricle
The innermost layer of blood vessels, that is composed of endothelium, is known as
Tunica intima
Which cranial nerves have a negative chronotropic effect on heart rate?
Vagus nerves
Which of the following cardiac dysrhythmias is immediately life-threatening and manifests on the electrocardiogram with chaotic activity?
Ventricular fibrillation
According to the Frank-Starling law, a bigger preload will result in
a stronger contraction
All of the following pairs correctly match the mechanisms affecting blood pressure with its effect except
aldosterone; decreased blood volume
A negative feedback mechanism will cause ______ if blood pressure drops
an increase in heart rate, stroke volume, and vasoconstriction
What blood vessels do ventricles always pump blood into?
arteries
______ carry blood away from the heat=rt, whereas ____ carry blood toward the heart
arteries; veins
The P wave on an electrocardiogram represents the depolarization of cells in the
atria
Which of the following hormones is released to decrease blood pressure?
atrial natriuretic peptide
The mitral valve is the clinical name for the
biscupid valve
is not one of the three main factors that influence blood pressure
blood reservoirs
Pulmonary arteries have ___________ blood pressure compared to systemic arteries
considerably lower
The right side of the heart receives
deoxygenated blood from the systemic circuit
What largely determines preload?
end-diastolic volume (EDV)
The visceral pericardium is the same as the
epicardium
High pressure blood in the ventricles
forces the semi lunar valves open
Decreased cardiac output may lead to
hypotension
Which cardiac chamber has the thickest wall?
left ventricle
Which chamber generates the highest pressure during systole?
left ventricle
The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called
preload
the _____________ is the only route in which arteries carry less oxygen than veins
pulmonary circuit
Oxygenated blood is delivered to the left atrium through the
pulmonary veins
What is initiated by a rapid influx of sodium ions into contractile cells creating a positive membrane potential inside the cell?
rapid depolarization phase
An increase in blood pressure will cause all of the following nerves to send impulses to the medulla oblongata except
sympathetic nerves
______ increases the diameter of a blood vessel
vasodilation
Both the left and right atria receive blood from
veins
Most blood is in the _____
veins