Mastering Bio Heart and Blood Vessels
__________ carry blood away from the heart and __________ carry blood toward the heart.
Arteries; veins
During which event of the cardiac cycle is systolic blood pressure measured?
Blood flows into the relaxed atria while the ventricles contract......The systolic blood pressure is the peak blood pressure resulting from ventricular contraction known as systole.
Increased pressure in the ventricles would close what valve(s)?
AV valves only...increased pressure in the ventricles would close the AV valves.
Which of the following is correct about the filling of the ventricles?
Most blood flows passively into the ventricles through open AV valves...most of the ventricular filling is passive; atrial contraction adds just a little more blood.
Which of the following represents the correct order in which electrical impulses will pass through the heart?
SA node, AV node, AV bundle, Purkinje fibers
Each of the following statements accurately describes a feature of arteries EXCEPT which one?
Valves along major arteries maintain directed blood flow.
Which of the following would interfere most with the ability of the veins to return blood to the heart?
absence of valves in the veins.....Valves in the veins are a major contributing factor to returning blood to the heart
All of the following mechanisms assist in returning venous blood to the heart, EXCEPT __________.
an increase in heart rate
As the blood travels through the circulatory system, the greatest drop in pressure occurs in the __________
arterioles
Which of the choices represents the order of vessels through which blood passes after leaving the heart?
artery, arteriole, capillary, venule, vein
Exchange of nutrients and gases between blood and tissues is the primary function of
capillaries
Which blood vessel is best suited for exchange of gases and nutrients with the surrounding tissue?
capillary
A pacemaker is used to correct __________
cardiac arrhythmias
A pacemaker is used to correct __________.
cardiac arrhythmias
How would a decrease in blood volume affect both stroke volume and cardiac output?
decreased stroke volume and no change in cardiac output.....a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in an effort to maintain cardiac output.
Blood pumped from the right ventricle is ________ and enters the ________.
deoxygenated, pulmonary trunk
Which layer of the heart is in contact with the blood?
endocardium
Which of the following represents the order of structures beginning inside the ventricle and traveling outward?
endocardium, myocardium, epicardium, pericardium (EMEP)
Which of the following would increase heart rate?
epinephrine and norepinephrine.....secreted by the adrenal medulla as a result of sympathetic stimulation, these hormones act as part of the sympathetic response, increasing heart rate.
Vasoconstriction causes an increase in the diameter of blood vessels, thus causing an increase in blood flow to the tissues.
false
True or false. The circulatory system of humans is composed of two circulatory loops: the systemic circulation, in which blood flows between the heart and lungs, and the pulmonary circulation, in which blood flows between the heart and the rest of the body.
false....The pulmonary circulation pumps blood from the heart to the lungs, whereas the systemic circulation pumps blood from the heart to the rest of the body.
What causes the aortic semilunar valve to close?
greater pressure in the aorta than in the left ventricle...backflow of blood in the aorta (towards the left ventricle) closes the aortic semilunar valve.
How would an increase in the sympathetic nervous system increase stroke volume?
increased contractility.....an increase in sympathetic nervous system activity would increase contractility (by increasing available calcium), thus increasing stroke volume. Contractility causes an increase in stroke volume by decreasing end systolic volume; it does not change end diastolic volume.
By what mechanism would an increase in venous return increase stroke volume?
increased end diastolic volume...an increase in venous return increases the end diastolic volume. The fibers are stretched more, resulting in an increase in the force of contraction (preload, or the Frank-Starling Mechanism).
Which of the following would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume....cardiac output = heart rate x stroke volume.
Vasodilation of arterioles __________ their diameter, __________ blood flow to the capillaries
increases; increasing.....As the arterioles are enlarged, the amount of blood flowing increases.
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
isovolumetric contraction, ventricular ejection, isovolumetric relaxation...the ventricles must contract and eject blood before they relax and fill again.
From the pulmonary veins, blood flows to the _____.
left atrium...Blood enters the left atrium via the pulmonary veins.
Which heart chamber receives blood from the pulmonary veins?
left atrium...the left atrium receives oxygenated blood from the pulmonary veins.
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
left ventricle...the left ventricle pumps oxygenated blood out the aorta to the entire body (systemic circuit).
A heart attack occurs as a result of __________.
narrowing or blockage of the coronary arteries
Blood pressure in veins is lower than that in arteries, and a series of ________ are necessary to prevent backflow of blood.
one way valves
The movement of blood through the pulmonary circuit transports __________.
oxygenated blood from the lungs to the heart...Blood that has been oxygenated in the lungs is returned to the heart through the pulmonary circuit.
When speaking about the circulatory system, we know that ________.
oxygenated blood leaves the left ventricle and travels to all parts of the body; it then returns to the heart and enters the right atrium...Oxygenated blood is pumped from the left ventricle to all parts of the body. When blood returns to the heart, it enters the right atrium.
The fibrous sac that surrounds the heart and produces lubricant for heart contraction is the
pericardium
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.
posterior vena cava...Blood enters the posterior vena cava from the capillaries of the abdominal organs and hind limbs.
In the functioning of the cardiovascular system, the heart provides __________, whereas the blood vessels provide __________.
power to move the blood; a network through which blood can flow...The heart moves the blood through the blood vessels.
Blood returns to the heart via the _____.
pulmonary veins...Pulmonary veins carry oxygenated blood from the lungs to the left atrium.
From the anterior vena cava, blood flows to the _____.
right atrium...Blood enters the right atrium from the anterior and posterior venae cavae.
Which chamber receives blood from the superior and inferior vena cavae?
right atrium...the right atrium receives unoxygenated blood from the systemic circuit.
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
right ventricle...the right ventricle pumps unoxygenated blood out the pulmonary trunk to the lungs.
The best definition of Korotkoff sounds would be ________.
the sounds heard through the stethoscope caused by the contracting and relaxing of the ventricles during the cardiac cycle...The Korotkoff sounds are the contraction/relaxation heart sounds produced in the brachial artery and heard when blood pressure is measured.
The function of the heart valves is ________.
to prevent backflow from the ventricles to the atria and from the great vessels back to the ventricles... The atrioventricular valves prevent backflow from the ventricles into the atria. The semilunar valves prevent backflow from the pulmonary arteries (pulmonary trunk) and aorta back into the ventricles.
The cardiac cycle consists of a period of heart contraction called systole and a period of heart relaxation called diastole.
true
The heart is actually (one, two, or three) pumps?
two pumps....the right side of the heart pumps to/from the lungs (pulmonary circuit) and the left side of the heart pumps to/from the rest of the body (the systemic circuit).
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
ventricular diastole... both occur during ventricular diastole when the ventricles are not actively contracting and ejecting blood.
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...higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.
An increase in cardiac output would result from all of the following, EXCEPT __________.
a decrease in heart rate...Decreased heart rate decreases cardiac output.