Medical Instrumentation I - Lecture 9 Quiz

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What is the primary mechanism by which an electrosurgical unit achieves cutting of tissue?

Thermal desiccation of the tissue
Continuous sinusoidal waveform (correct)
Series of sinusoidal wave packets
Mechanical disruption of the tissue

What is the main difference between the monopolar and bipolar modes of operation of an electrosurgical unit?

The method in which the current enters and leaves the tissue (correct)
The waveform used to achieve cutting versus coagulation
The type of tissue being operated on
The power output of the device

At what temperature range do irreversible changes in the tissue occur during electrosurgery?

Above 45°C (correct)
Above 40°C
Above 37°C
Above 50°C

What is the primary mechanism by which an electrosurgical unit achieves coagulation of tissue?

Series of sinusoidal wave packets (A) Signup and view all the answers

What is the primary purpose of using an electrosurgical unit during a surgical procedure?

To cut tissue effectively while controlling bleeding (D) Signup and view all the answers

What is the temperature range at which reversible changes in the tissue occur during electrosurgery?

Up to 45°C (C) Signup and view all the answers

What are the specific surgical effects achieved by passing high-frequency electric currents through biological tissues using an electrosurgical unit (ESU)?

Cutting, coagulation, and vaporization (C) Signup and view all the answers

What is the main difference between monopolar and bipolar electrosurgical units?

Monopolar uses a single electrode, while bipolar uses two electrodes (D) Signup and view all the answers

What is the purpose of the dispersive electrode used in monopolar electrosurgery?

To provide a return path for the current from the active electrode (A) Signup and view all the answers

What is the relationship between current density and tissue damage in electrosurgery?

Higher current density leads to more tissue damage (A) Signup and view all the answers

What are the main components of an electrosurgical unit (ESU) circuit?

Power source, active electrode, and dispersive electrode (A) Signup and view all the answers

What is the purpose of testing the electrosurgical unit (ESU)?

To ensure the ESU is functioning properly and safely (C) Signup and view all the answers

What is the primary purpose of zonal centrifugation?

To separate molecules based on their sedimentation coefficient (C) Signup and view all the answers

Which of the following is a key advantage of zonal centrifugation over isopycnic centrifugation?

It is a mild, non-denaturing procedure useful for protein purification (A) Signup and view all the answers

What is the main difference between zonal centrifugation and isopycnic centrifugation?

Zonal centrifugation separates particles based on sedimentation coefficient, while isopycnic centrifugation separates based on density (B) Signup and view all the answers

Which property of a particle determines its sedimentation coefficient in zonal centrifugation?

The particle's size and shape (B) Signup and view all the answers

Why is the sucrose or Ficoll gradient used in zonal centrifugation important?

It provides buoyancy and prevents particles from floating to the top of the tube (C) Signup and view all the answers

Which type of centrifugation is better suited for purifying nucleic acid species of different densities?

Isopycnic centrifugation (C) Signup and view all the answers

What does the frictional coefficient and particle velocity represent in the context of the text?

Factors influencing sedimentation forces (D) Signup and view all the answers

Why is the use of a density gradient important in centrifugation according to the text?

To prevent convection mixing of solute bands (D) Signup and view all the answers

What technique is specifically mentioned for determining sedimentation coefficients and molecular masses?

Analytical ultracentrifugation (C) Signup and view all the answers

In the context of the text, what is the purpose of creating a density gradient in the tube?

To purify proteins and nucleic acids (A) Signup and view all the answers

What would happen if a layer of concentrated, dense solution overlaid a less dense solvent in centrifugation?

Mixing by convection (B) Signup and view all the answers

How are moving boundaries and concentration distributions observed in analytical ultracentrifugation according to the text?

Using optical devices (B) Signup and view all the answers

What is the main feature that distinguishes a compound microscope?

It uses multiple lenses to magnify the image (A) Signup and view all the answers

What is the function of the objective lens in a compound microscope?

It is closest to the object or specimen (A) Signup and view all the answers

How is the image produced at the eye with a compound microscope described?

Two-dimensional and reversed (A) Signup and view all the answers

What type of light method is most commonly used in a compound microscope for illuminating the specimen?

Reflected light from a mirror (D) Signup and view all the answers

At what magnification level can much detail at the cellular level of biological specimens be seen with a compound microscope?

$500x$ (A) Signup and view all the answers

Which type of microscope is mentioned as the second most common in the text?

Stereo microscope (A) Signup and view all the answers