In vivo Biofluid Mechanics - Biofluidmechanics: An Introduction to Fluid Mechanics Macrocirculation and Microcirculation - page 368

CHAPTER
15

In vi vo Biofluid Mecha nics

LEARNING OUTCOMES

1. Discuss the need and use of live animal

preparations in biofluid mechanics

4. Calculate the apparent Doppler frequency

shift

2. Describe the necessary components of an

intravital microscopy system

5. Discuss magnetic resonance imaging

techniques

3. Explain the use of Doppler ultrasound

technology

6. Understand the physics behind magnetic

resonance imaging

15.1 LIVE ANIMAL PREPARATIONS

Although there is a great deal of information that can be learned from in vitro experi-

ments, studies may provide the closest, most accurate, and most relevant models

for researchers to understand what occurs under undisturbed physiological conditions.
We make this distinction between disturbed conditions and undisturbed conditions
because we will focus this section on intravital microscopy, which is a technique where a
vascular bed is dissected out of the animal, but it remains connected to the feeding vessels,
nerve cells, musculature, and other biological structures. Therefore, the vascular system
under investigation (usually from muscle) is still under physiological regulation (nervous,
hormonal, among others), but there may be some other unanticipated factors. For these
experiments, animals are placed under anesthesia to allow for the researcher to dissect
the tissue, and then comprehensive observations of changes within the flow conditions
can be made throughout the dissected tissue. Traditional intravital microscopy uses the
mesenteric capillary beds to observe changes in flow under various conditions of interest.
This capillary bed is used because it is relatively easy to access and the tissue is relatively
transparent, so that optical microscopes in conjunction with recording equipment can be
used to document the flow through the vascular bed.

in vivo