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Biophysics Quiz on Chapter 4, created by Y Y on 26/06/2019.

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Chapter 4

Question 1 of 37

1

Which of the following terms is NOT one of the known types of tissue-polarization due to
application of an external electric current?

Select one of the following:

  • a) electronic polarization;

  • b) electrode polarization;

  • c) electret polarization.

Explanation

Question 2 of 37

1

How many different types of polarization in living tissue can be accounted for?

Select one of the following:

  • a) two;

  • b) nine;

  • c) six.

Explanation

Question 3 of 37

1

Which of the following tissue-polarization types has the longest time constant?

Select one of the following:

  • a) electrode polarization;

  • b) dipole polarization;

  • c) macrostructural polarization.

Explanation

Question 4 of 37

1

Which of the following types of polarization takes place 10-16 s after the application of external
current through the tissue?

Select one of the following:

  • a) electronic;

  • b) ionic;

  • c) superficial.

Explanation

Question 5 of 37

1

Choose the correct relationship between the frequency of alternating current (AC) and the
number of different types of polarizations that take place in the tissue:

Select one of the following:

  • a) higher frequency → higher number of polarizations;

  • b) lower frequency → higher number of polarizations;

  • c) lower frequency → lower number of polarizations.

Explanation

Question 6 of 37

1

What happens to the current passing through living tissue, when a constant DC voltage is applied
across?

Select one of the following:

  • a) current increases continuously;

  • b) current decreases exponentially;

  • c) current remains constant.

Explanation

Question 7 of 37

1

What causes the decrease of the DC current passing through living tissue?

c

Select one of the following:

  • a) generation of polarization potential, opposing the external voltage;

  • b) increase of the internal resistance of the tissue;

  • ) the leakage of charge out of the tissue.

Explanation

Question 8 of 37

1

What is the path of the electric current through the body of patient who is subjected to
galvanization?

Select one of the following:

  • a) through the cytosol;

  • b) through the interstitial spaces;

  • c) through cellular membranes, via nexus junctions between cells.

Explanation

Question 9 of 37

1

What type of polarization occurs in the double electric layers surrounding cells, suspended in
ionic solution, when constant electric field is applied?

Select one of the following:

  • a) surface polarization;

  • b) macrostructural polarization;

  • c) orientational polarization.

Explanation

Question 10 of 37

1

Which of the following types of polarization occur within the cell volume, due to the application of
a constant electric field?

Select one of the following:

  • a) superficial polarization;

  • b) macrostructural polarization;

  • c) electrode polarization.

Explanation

Question 11 of 37

1

What type of impedance to the propagation of electric current is found in living tissues?

Select one of the following:

  • a) resistive and capacitive;

  • b) resistive and inductive;

  • c) capacitive and inductive.

Explanation

Question 12 of 37

1

What is the predominant type of electrical impedance in cellular fluids?

Select one of the following:

  • a) resistive, because cellular fluids are rich in electrolytes;

  • b) capacitive, because cellular fluids have sub-structures;

  • c) inductive, because there are inductive currents in the fluids.

Explanation

Question 13 of 37

1

What causes the capacitive properties of biological tissue?

Select one of the following:

  • a) extra- and intra-cellular fluids;

  • b) cellular and intra-cellular membranes;

  • c) the free movement of ions.

Explanation

Question 14 of 37

1

The neuromuscular junction (myoneural synapse) is:

Select one of the following:

  • a) a type of action potential;

  • b) the location where a neuronal excitation is transferred to a muscle;

  • c) the structure that opens voltage-gated Ca2+ channels.

Explanation

Question 15 of 37

1

In which of the following practices uses electro-muscular stimulation?

Select one of the following:

  • a) echography;

  • b) physical therapy;

  • c) electrophoresis.

Explanation

Question 16 of 37

1

When direct current (DC) is applied through biological tissue:

Select one of the following:

  • a) there is polarization of dissolved ions;

  • b) the conductivity of the cell increases due to temperature increase;

  • c) the current will decrease with time.

Explanation

Question 17 of 37

1

When pulsed current is applied through biological tissue:

Select one of the following:

  • a) there will be polarization of the ion channels;

  • b) the conductivity of the cell increases due heating;

  • c) the current decreases with time.

Explanation

Question 18 of 37

1

When very high frequency alternating current (AC) is applied through biological tissue:

Select one of the following:

  • a) there is a polarization of the ion channels;

  • b) there is a heating effect;

  • c) there is a decrease of the current due to accommodation.

Explanation

Question 19 of 37

1

Which of the following is related to dipole polarization?

Select one of the following:

  • a) the reorientation of mostly water molecules due an external field;

  • b) the conversion of the double electric layer into directional dipoles;

  • c) the formation of dipole moment due to the external field.

Explanation

Question 20 of 37

1

Dipole polarization:

Select one of the following:

  • a) is related mostly to water molecules;

  • b) involves the formation of a double electric layer;

  • c) decreases the intercellular communication.

Explanation

Question 21 of 37

1

Ionic polarization:

Select one of the following:

  • a) involves mostly water molecules;

  • b) relates to the formation of a double electric layer;

  • c) increases the electromotive force (EMF) generated in biological tissue.

Explanation

Question 22 of 37

1

165. Ionic and dipole polarizations:

Select one of the following:

  • a) occur predominately in bone tissue;

  • b) cause heating in soft tissue;

  • c) decrease the magnitude of currents passing through soft tissue.

Explanation

Question 23 of 37

1

Electro-muscular stimulation is used in the following condition:

Select one of the following:

  • a) epilepsy;

  • b) arrhythmia;

  • c) muscle atrophy.

Explanation

Question 24 of 37

1

When the frequency of electrical stimulation is increased significantly, skeletal muscles will
respond with:

Select one of the following:

  • a) a muscle twitch;

  • b) muscle relaxation;

  • c) complete tetanus.

Explanation

Question 25 of 37

1

For efficient electro-muscular stimulation this type of current is used:

Select one of the following:

  • a) pulsed current above the threshold;

  • b) direct current with high voltage;

  • c) direct current with variable voltage.

Explanation

Question 26 of 37

1

When constant direct current is applied to living tissue, the magnitude of the current will
decrease with time. What is the explanation?

Select one of the following:

  • a) the activation of voltage-gated Ca2+ channels;

  • b) the increase of the active resistance of the skin;

  • c) the polarization of the tissue.

Explanation

Question 27 of 37

1

Electro-muscular stimulation is used for:

Select one of the following:

  • a) observation of the spontaneous contractions in smooth muscles of the gastrointestinal tract;

  • b) conditioning mostly of skeletal muscles;

  • c) stimulation of the peripheral nerves.

Explanation

Question 28 of 37

1

The electrical conductance of biological tissue is:

Select one of the following:

  • a) a passive property;

  • b) an active property;

  • c) biological tissue has only resistance.

Explanation

Question 29 of 37

1

Choose the INCORRECT statement regarding the conductance of direct current (DC) through
biological tissues:

Select one of the following:

  • a) DC does not flow through cells, only in the extracellular fluid;

  • b) DC flows through the cells;

  • c) DC decreases exponentially with time, regarding of the applied constant voltage.

Explanation

Question 30 of 37

1

Single muscle twitch is cause by:

Select one of the following:

  • a) sub-threshold stimulation;

  • b) single action potential;

  • c) a series of fast local responses.

Explanation

Question 31 of 37

1

Tetanic muscle contractions are the result of:

Select one of the following:

  • a) a series of sub-threshold stimuli;

  • b) a series of over-threshold stimuli;

  • c) a series of fast local responses.

Explanation

Question 32 of 37

1

Choose the best definition for tetanic muscle contraction:

Select one of the following:

  • a) series of fast sequential muscle contractions;

  • b) series of muscle contractions, where new contractions begin before the ending of previous contractions;

  • c) group of sequential muscle contractions, triggered by singlesub-threshold stimulation.

Explanation

Question 33 of 37

1

A complete (smooth) tetanus is achieved when:

Select one of the following:

  • a) the interval between action potentials is shorter than the duration of the muscle contraction;

  • b) the interval between action potentials is longer than the duration of the muscle contraction;

  • c) when the duration of the action potential is longer then the duration of the muscle contraction.

Explanation

Question 34 of 37

1

Electro-muscular contraction of denervated muscles is:

Select one of the following:

  • a) a muscle contraction resulting from depolarization;

  • b) a muscle contraction triggered by a high voltage;

  • c) a muscle relaxation following the polarization of muscle cells.

Explanation

Question 35 of 37

1

The specific electrical conductance is the greatest for this type of tissue:

Select one of the following:

  • a) blood;

  • b) muscle tissue;

  • c) fat tissue.

Explanation

Question 36 of 37

1

When constant magnitude voltage is applied to biological tissue the resulting current does not
follow Ohm’s law. This is due to:

Select one of the following:

  • a) depolarization;

  • b) polarization;

  • c) induction.

Explanation

Question 37 of 37

1

Electro-muscular stimulation for physical therapy uses:

Select one of the following:

  • a) low frequency pulsed current;

  • b) high frequency pulsed current;

  • c) sine-wave current.

Explanation

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