# Physio 9.0 Cardio Lab Report

Topics: Blood, Heart, Fluid dynamics Pages: 8 (2277 words) Published: January 5, 2013
Physio Cardio Lab Report Answers

Activity 1 Questions:

1. Explain how the body establishes a pressure gradient for fluid flow.

Pressure gradient is the flow rate of a liquid through a pipe. This is directly proportional to the difference between the pressures at the two ends of the pipe and inversely proportional to the pip's resistance. The pressure gradient is directly dependent upon blood vessel radius which essentially controls blood flow. The bigger the blood vessel radius, the more blood flow or fluid flow. The smaller blood vessel radius, the lesson blood or fluid flow.

2. Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your prediction?

Flow tube radius change has a direct effect on flow rate. As evidenced in this lab, when flow tube radius was increased, the flow rate was also increased. They are directly proportional. As evidenced from the text, when flow tube radius increases in a blood vessel, the flow rate is much more free flowing and flows a lot quicker as the radius is increased. When starting with 1.5mm of radius, the flow was very slow, yet when increased to 2mm, 3mm, and eventually to 5mm, the flow within the blood vessel incrementally increased.

3. Describe the effect that radius changes have on the laminar flow of a fluid.

Laminar Flow is defined as the free-flowing blood in the middle of the vessel. Radius change is directly proportional on laminar flow. In a constricted vessel, proportionately more blood is in contact with the vessel wall and there is less laminar flow, significantly diminishing the rate of blood flow in the vessel, yet if the vessel is more dilated, or the radius is increased, more blood flow is able to get in, thus increasing the blood flow. The bigger the radius, the more laminar flow of fluid.

4. 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?

If the variables are radius on the X-axis and flow rate on the Y-axis, the experiment called for the experimenter to incrementally increase the radius and plot the results. As we know, radius is directly proportional to flow rate in that as the radius increases so does the flow rate, therefore, the plotted graph has to be linear. If one increases, so does the other going in a straight line!

Activity 2 Questions:

1. Describe the components in the blood that affect viscosity?

The components in the blood that affect viscosity are the presences of plasma proteins and formed elements such as white blood cells (leukocytes), red blood cells (erythrocytes), and platelets. When these formed elements and plasma proteins in the blood slide past one another, there is an increase in the resistance to flow.

2. Explain the effect that the viscosity change had on flow rate. How well did the results compare with your prediction?

Viscosity is defined as the thickness or stickiness of a fluid. In regards to flow rate, they are inversely comparable and thus as you increase viscosity or the “thickness” of the blood, the flow rate decreases. As seen in the graph, increasing the viscosity inversely decreases the flow rate each time you increased it by 1.

3. Describe the graph of flow versus viscosity.

As evidenced in the graph, the constants in this experiment were radius, length, and pressure. The variables were flow rate and viscosity. The y axis represented flow rate and the x axis represented viscosity. As viscosity increased, the flow rate decreased causing a linear or inverse curve relationship going down.

4. Discuss the effect that polycythemia would have on viscosity and on blood flow.

Polycythemia is a condition in which excess red blood cells are present. We learned earlier that an increase in red blood cells results in an increase in blood viscosity. An increase in blood viscosity directly affects blood flow,...

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