Chapter 4

a) electronic polarization;

b) electrode polarization;

c) electret polarization.

a) two;

b) nine;

c) six.

a) electrode polarization;

b) dipole polarization;

c) macrostructural polarization.

a) electronic;

b) ionic;

c) superficial.

a) higher frequency → higher number of polarizations;

b) lower frequency → higher number of polarizations;

c) lower frequency → lower number of polarizations.

a) current increases continuously;

b) current decreases exponentially;

c) current remains constant.

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.

a) through the cytosol;

b) through the interstitial spaces;

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

a) surface polarization;

b) macrostructural polarization;

c) orientational polarization.

a) superficial polarization;

b) macrostructural polarization;

c) electrode polarization.

a) resistive and capacitive;

b) resistive and inductive;

c) capacitive and inductive.

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.

a) extra- and intra-cellular fluids;

b) cellular and intra-cellular membranes;

c) the free movement of ions.

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.

a) echography;

b) physical therapy;

c) electrophoresis.

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.

a) there will be polarization of the ion channels;

b) the conductivity of the cell increases due heating;

c) the current decreases with time.

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.

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.

a) is related mostly to water molecules;

b) involves the formation of a double electric layer;

c) decreases the intercellular communication.

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.

a) occur predominately in bone tissue;

b) cause heating in soft tissue;

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

a) epilepsy;

b) arrhythmia;

c) muscle atrophy.

a) a muscle twitch;

b) muscle relaxation;

c) complete tetanus.

a) pulsed current above the threshold;

b) direct current with high voltage;

c) direct current with variable voltage.

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

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

c) the polarization of the tissue.

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.

a) a passive property;

b) an active property;

c) biological tissue has only resistance.

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.

a) sub-threshold stimulation;

b) single action potential;

c) a series of fast local responses.

a) a series of sub-threshold stimuli;

b) a series of over-threshold stimuli;

c) a series of fast local responses.

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.

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.

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.

a) blood;

b) muscle tissue;

c) fat tissue.

a) depolarization;

b) polarization;

c) induction.

a) low frequency pulsed current;

b) high frequency pulsed current;

c) sine-wave current.