How does the body decrease the blood vessel radius?
answer
vasoconstriction
question
When the radius of the flow tube is decreased, the _______.
answer
fluid flow rate decreases
question
During exercise, we might expect blood vessels in the skeletal muscle to be somewhat _______________ and the blood vessels in the digestive organs to be somewhat ____________.
answer
dilated, constricted
question
Laminar flow of the blood is achieved through _______.
answer
vasodilation
question
The free-flowing blood located in the middle of a blood vessel is called _______.
answer
laminar flow
question
The flow rate of a liquid is _______.
answer
directly proportional to the pressure gradient
question
Which of the following is INCORRECTLY matched with the corresponding equipment used in this experiment?
answer
All of the above are matched correctly.
question
Which of the following has the greatest effect on peripheral resistance?
answer
blood vessel diameter
question
Explain how the body establishes a pressure gradient for fluid flow.
answer
Fluids are naturally influenced to flow from an area of higher pressure to an area of lower pressure. Blood vessels will contract in one location and dilate in another location in order to direct blood flow in a certain way.
question
[Show student response to predict question]. Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your prediction?
answer
When the radius of the tube increases, the flow rate also increases. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Describe the effect that radius changes have on the laminar flow of a fluid.
answer
Laminar flow is when a fluid travels in parallel layers and its flow is not turbulent. If the tube radius is increased, then the laminar flow will increase. If the tube radius is decreased, then the laminar flow will decrease.
question
[Show student response to predict question] Why do you think the plot was not linear? (Hint: look at the relationship of the variables in the equation). How well did the results compare with your prediction?
answer
The graph ended up not being linear, because there is an exponential relationship between the variables (when the radius changes slightly, the flow rate increases dramatically). ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
In this activity, which of the following were kept constant?
answer
blood vessel radius and blood vessel length
question
Which of the following describes the graph of flow versus viscosity?
answer
As viscosity increased, the flow rate decreased and the graph was curved.
question
Which viscosity had the fastest flow rate?
answer
1
question
What is the typical range for viscosity of the blood?
answer
3 to 5
question
Polycythemia results in _______.
answer
increased resistance to flow
question
What is the effect of increased viscosity?
answer
decreased flow rate
question
Formed elements in the blood _______.
answer
include platelets and whole cells that slide past one another
question
Which of the following is INCORRECTLY matched?
answer
thrombocytes - plasma proteins
question
Describe the components in the blood that affect viscosity.
answer
There are many different components in blood that can affect its viscosity. White blood cells, red blood cells, platelets, and proteins suspended in the blood plasma are examples of these components.
question
[Show student response to predict question]. Explain the effect that the viscosity change had on flow rate. How well did the results compare with your prediction?
answer
Increased viscosity causes flow rate to decrease. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Describe the graph of flow versus viscosity.
answer
The graph of flow versus viscosity looked similar to the last graph but it is flipped from left to right. This means it is a negative exponential graph (exponential decay).
question
Discuss the effect that polycythemia would have on viscosity and on blood flow.
answer
Polycythemia is a condition where a person has too many red blood cells. An increased number of red blood cells (formed elements) means that the blood would be more viscous. Blood viscosity has a negative effect on blood flow rate, so polycythemia would decrease blood flow.
question
Increasing blood vessel length _______.
answer
has the same effect as decreasing blood vessel radius and increases resistance to flow
question
Which flow tube length had the greatest flow rate?
answer
10 mm
question
Which of the following has the greatest effect on blood flow?
answer
blood vessel radius
question
Which of the following describes why the body might need to increase vessel length?
answer
to accommodate weight gain and height changes
question
When blood vessel length increases, _______.
answer
surface area increases
question
Which of the following is true of blood vessel length?
answer
It increases as we approach puberty.
question
In this experiment, _______.
answer
blood vessel radius will be kept constant and blood vessel length will be varied
question
Which is more likely to occur, a change in blood vessel radius or a change in blood vessel length? Explain why.
answer
Blood vessel radius is more likely to change because blood vessels are able to constrict and dilate. Blood vessel length does not usually change when we reach adulthood.
question
[Show student response to predict question]. Explain the effect that the change in blood vessel length had on flow rate. How well did the results compare with your prediction?
answer
An increase in the length of the blood vessel caused blood flow to decrease. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Explain why you think blood vessel radius can have a larger effect on the body than changes in blood vessel length (use the blood flow equation).
answer
Relating to the blood flow equation, the radius is taken to the fourth power. This means it has a much larger effect on the rate of blood flow than the length of the blood vessel does. The radius also has a much larger effect because vasodilation and vasoconstriction can actively change the radius but blood vessel length doesn't usually change when a person reaches adulthood.
question
Describe the effect that obesity would have on blood flow and why.
answer
Obesity would have a negative effect on blood flow. This is because when a person gains excess weight, the blood vessels of the body have to change their length in order to supply the body with the blood it needs. With an increased blood vessel length, the flow rate would decrease.
question
Which of the following result(s) in an increase in fluid flow rate?
answer
increase in pressure and increase in radius diameter
question
Describe the plot of pressure versus flow rate.
answer
It was linear, and the flow rate increased with increased pressure.
question
In this activity, we changed the pressure delivered by the left beaker. This is analogous to _______.
answer
increasing the force of contraction of the heart
question
In this activity, which variable will be changed?
answer
pressure
question
Arteries that are closer to the heart _______.
answer
have more elastic tissue and must be able to withstand pressure changes
question
In the cardiovascular system, the pressure gradient is provided by _______.
answer
the force of contraction of the heart and peripheral resistance in the blood vessels
question
Blood flow is _______.
answer
directly proportional to the pressure gradient
question
[Show student response to predict question]. Explain the effect that pressure changes had on flow rate. How well did the results compare with your prediction?
answer
An increase in pressure causes an increase in flow rate. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
[Show student response to predict question] How does the plot differ from the plots for tube radius, viscosity, and tube length? How well did the results compare with your prediction?
answer
The plots for tube radius, viscosity, and tube length were graphs with exponential changes. However, the graph for this plot showed linear growth. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Explain why pressure changes are not the best way to control blood flow.
answer
It is very easy for the body to control the diameter of its blood vessels through vasodilation and vasoconstriction. However, if the body has to rely on the heart responding to different forces and pressures. Usually, it is the heart changing contraction forces and the blood vessels reacting and adapting to it, but it would be difficult for the system to work the other way around.
question
Use your data to calculate the increase in flow rate in ml/min/mm Hg.
answer
The increase in flow rate was 1.4 ml/min/mm of mercury.
question
The volume in the pump when the pump piston is all the way down represents the _______.
answer
end systolic volume
question
When the flow tube radius increased, _______.
answer
resistance decreased and pump rate increased to maintain pressure
question
Which of the following stayed constant throughout this activity?
answer
stroke volume
question
Which right flow tube radius resulted in the fastest flow rate?
answer
5.0 mm
question
During the ejection period, _______.
answer
blood is pumped into the aorta and the pulmonary trunk
question
Cardiac output is _______.
answer
All of the above.
question
The left side of the heart pumps blood _______.
answer
through the aortic valve
question
What variable(s) can the cardiovascular system alter to maintain blood pressure?
answer
heart rate, stroke volume and resistance
question
[Show student response to predict question]. Explain the effect of increasing the right flow tube radius on the flow rate, resistance, and pump rate.
answer
Increasing the flow tube radius caused flow rate to increase and resistance to decrease. To maintain the same pressure, the pump rate had to increase as well. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Describe what the left and right beakers in the experiment correspond to in the human heart.
answer
The left beaker in the experiment represents the blood supply coming from the lungs. The right beaker represents the blood supply that travels to the systemic circuit.
question
Briefly describe how the human heart could compensate for flow rate changes to maintain blood pressure.
answer
If the flow rate increases, the heart would have to pump faster to maintain the body's blood pressure.
question
Increase in stroke volume is a result of _______.
answer
increased contractility of the heart, increased EDV and increased preload
question
Which variable was altered in this activity?
answer
stroke volume
question
An increase in venous return _______.
answer
occurs during exercise
question
The flow rate in this activity _______.
answer
stayed constant, because pump rate decreased as the stroke volume increased
question
An increase in venous return will _______.
answer
increase EDV and therefore, increase stroke volume
question
The overlap length of cardiac muscle in the healthy heart is _______.
answer
less than optimum for maximum tension production
question
Afterload is the pressure threshold that must be exceeded to open _______.
answer
the aortic semilunar valve and the pulmonary semilunar valve
question
An increased preload is equivalent to, or causes, a(n) _______.
answer
increased EDV
question
Describe the Frank-Starling law in the heart.
answer
The Frank Starling Law states that the stroke volume of the heart increases in response to an increase in blood volume filling up the heart.
question
[Show student response to predict question]. Explain what happened to the pump rate when you increased the stroke volume? Why do you think this occurred? How well did the results compare with your prediction?
answer
When the stroke volume increased, the pump rate increased to maintain the cardiac output. This is because stroke volume and pump rate are the two factors that contribute to the calculation of cardiac output. (If one increases, the other must decrease and vice versa.) ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Describe how the heart alters stroke volume.
answer
The heart alters stroke volume by changing its contractibility.
question
Describe the intrinsic factors that control stroke volume.
answer
There are three factors that contribute to stroke volume. One is preload, which is the filling pressure in the heart at the end of diastole. Another is contractility, which is the heart's natural force of contraction during systole. The last is afterload, which is the pressure that the heart is working against to pump blood during systole.
question
Increasing the left flow tube radius corresponds to _______.
answer
increasing preload
question
In this activity, the pump simulates the _______.
answer
left ventricle
question
When the left flow tube radius was increased, _______.
answer
the flow rate increased
question
Patients with aortic valve stenosis experience _______.
answer
increased thickness in the myocardium and a decrease in chamber volume
question
Aortic valve stenosis is characterized by _______.
answer
increased resistance to blood flow, thickening of the myocardium and narrowing of the aortic semilunar valve
question
In this activity, the right flow tube simulates the _______.
answer
aorta
question
The compensating mechanisms tested in this activity include all of the following EXCEPT _______.
answer
decreasing preload
question
In the activity, decreasing pressure in the right beaker is analogous to _______.
answer
decreasing afterload
question
Explain how the heart could compensate for changes in peripheral resistance.
answer
When there is a higher heart rate, peripheral resistance is higher to have the same volume of blood moving through the blood vessels. (They are directly proportional.)
question
[Show student response to predict question]. Which mechanism had the greatest compensatory effect? How well did the results compare with your prediction?
answer
Contractility had the greatest compensatory effect. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
[Show student response to predict question]. Explain what happened when the pump pressure and the beaker pressure were the same. How well did the results compare with your prediction?
answer
When the pressures were the same, no blood flow occurred because a difference in pressures is required to move the blood. ((Remember to put whether or not you predicted this correctly according to the questions in the virtual lab!))
question
Explain whether it would be better to adjust heart rate or blood vessel diameter to achieve blood flow changes at a local level (for example, in just the digestive system).
answer
It would be better for the heart to adjust the blood vessel diameter because an irregularly high heart rate can cause complications and put strain on the heart muscles.
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