Chapter 6

Blood is primarily transported through the venous system by a. increasing the intravascular blood pressure. b. muscle contractions. c. venous valve system. d. \(b\) and \(c\).

Which of the following changes would have the most significant effect on increasing the vascular resistance? a. Doubling the blood vessel diameter b. Halving the blood vessel length c. Doubling the blood viscosity d. Halving the blood vessel diameter e. Doubling the blood vessel length

Discuss the salient anatomical differences between arteries and veins, and detail how this relates to the function of each blood vessel.

Why is the blood flow to some organs (such as the stomach, intestines) discontinuous and the blood flow to other organs (such as the brain, heart) continuous?

Discuss the important proteins that are found in plasma. Why are the concentrations of these proteins so tightly regulated?

Discuss coagulation and the role of platelets in the coagulation process.

When you are dehydrated, it would cause an (increase or decrease) in the hematocrit. What effect would this have on blood flow, viscosity, blood pressure, etc?

The three cellular components of blood have different anatomical structures that relate to their functions. Briefly discuss the important structures for each cellular component.

When a patient experiences high blood pressure, discuss what happens to the vascular flow rate. What changes must occur to allow the vascular flow rate return to normal conditions? Assume that the peak systolic blood pressure for the hypertensive patient is \(190 \mathrm{mmHg}\) and that the diastolic pressure is \(130 \mathrm{mmHg}\). Compare this flow with the normotensive case \((120 / 80 \mathrm{mmHg})\).

The velocity through a tapering channel can be estimated as \(\vec{v}=v_{i}\left(1-e^{t}\right) \hat{i}\). Calculate the acceleration of any particle along the centerline and the position of a particle that is located at \(x=0\) at time 0 , where \(L\) is the vessel length and \(v_{i}\) is the inflow centerline velocity.

Under atherosclerotic conditions, the aorta can reduce in cross-sectional area. Is it more likely for the blood flow to remain laminar or become turbulent? What would happen to the blood flow if there is an aneurysm present within the aorta?

Show that the volumetric flow rate for a Casson model of blood flow is $$ Q=\frac{\pi R^{4}}{8 \eta}\left[-\frac{d p}{d x}-\frac{16}{7}\left(\frac{2 \tau_{y}}{R}\right)^{0.5}\left(-\frac{d p}{d x}\right)^{0.5}+\frac{4}{3}\left(\frac{2 \tau_{y}}{R}\right)^{4}\left(-\frac{d p}{d x}\right)^{-3}\right] $$

If the diameter of a person's aorta is abnormally large, would the flow through the aorta more likely be laminar or turbulent? What if the heart rate is increased but flow rate is maintained the same?