Biophysics 2

The ultarsonograph emits a pulse of ultrasound wave into the examined material  at the time t=0. The echo is detected after 0,2ms (millisecond). Assuming the sound velocity in the material 500 m/s, indicate the distance between the ultrasonography´s head and the object from which the sound was reflected:

Indicate in which case action potential is propagated with a constant amplitude 

Indicate in which case the action potential is not propagated with a constant amplitude:

Fourier theorem applies to 

If the intracellular concentration of a given is qual to the extracellular one the Nernst equilibrium potential for this ion is 

The resting membrane potential occurs in conditions in which 

Indicate how an increase in the intracellular concentration of the chloride ions will affect the membrane potential (assuming concentrations of all other ions uncharged).

Indicate which effect on the action potential time course would have an acceleration of the activation process of the voltage-gated potassium channels (assuming that the applied stimulus exceeds activation threshold)

Indicate the true sentence 

Choose the best characterization of myasthenia gravis

If the membrane resistance of the axon increases 16 times, the space constant axon 

Velocity  of depolarization propagation in the ventricular muscles is approximately 

Figure below represents a dipole. The value of the electrical potential at the localization indicated as "R" is equal to V. Indicate the value of the potential at the localization "2R" 

Indicate the type of channel responsible for a slow depolarization of the diastole potential in the sino-atrial node 

Indicate the type of channel involved in existence of the plateau phase of action potential in ventricular muscles (all myocytes in the heart not only ventricles) 

Indicate the cell type in the heart is which rapid onset of action potential is mediated by voltage-gated sodium channels 

Acetylcholine (Ach) released from vagus nerve decreases the heartbeat rate. Indicate

the correct mechanism of Ach action 

Indicate the extent to which the measured atrial pressure (in mm Hg) can be affected by the hydrostatic blood pressure (in the case of, for instance, inappropriate patiet’s posture) 

When a viscous fluid is transported through a cylindrical vessel of constant diameter and under a constant pressure the fluid velocity 

Parameter Q defines the volume of viscous liquid transported per unit time through a cylindrical vessel. If the length of the vessel is reduced by 50% and the liquif viscosity is increased twice, how much is do the parameter Q will change (assuming that all other parameters including pressure remain the same)? 

Indicate conditions in which diffraction is expected to occur 

Synaptic transmission at the rod’s synapse occurs at its maximum rate 

 The angular resolution limit (smaller di____ angle) of eye is 

Astigmatism takes place in a spherical lens 

For a thick lens, the distance between the object and the lens is measured as 

What happens to the optical power of an initially symmetrical lens if one of its curvature radii gets 50% shorter and the other remains unchanged? 

When focusing on a very distant object, human eye has the optical power of approximately 

The closed system containing the ideal gas is being expanded (increasing its volume) without exchanging heat with the environment. The internal energy of this system is 

Fro the open system the chemical potential (p) for a given compound defined as 

how the osmotic pressure (according to the Vant Hoff’s law) depends on the solute concentration c 

The considered system can be found in the two states, state S1 characterized by the energy U1 and state S2 characterized by the energy U2. If U1<U2 then 

Indicate how the energy of interactions between two points charges depends on the distance (r) between those charges 

in the interactions described by Van der Waals (A,B-constants <0, r in distance) 

if the frequency is reduced by 50% (becomes on half of the initial value) and the velocity of the wave propagation is underchanged then 

How much the sound intensity must increase to produce the sensation of increase in loudness by 200% 

Upon movement of the basilar membrane, the membrane of the outer hair cells is

Prestin is 

Ultrasound frequency increased by 100% indicates how much changed the acoustic impedance within a homogenous medium 

 Indicate proper antigenates 

The harmonic force (i.e. the force inducing the harmonic movement) is given by the following formula (F-force, k-spring constant, A-amplitude, y- displacement)