1st semester: Electrophysiology

Question 1

A stronger than 3 threshold stimulus intensity can initiate another action potential during the time when there is continued conductance to ______ creating a more negative potential than the RMP

Answer 1

potassium [this is true for REFRACTORY period]

Question 2

To regulate the volume of cells in a hypotonic medium which of the following happens?
The osmolytes are transported _____

Answer 2

out of the cell to promote regulatory volume decrease

Question 3

Rate of diffusion is faster in/for gases like

Answer 3

O2 and CO2

Question 4

simple diffusion is under

Answer 4

passive diffusion

Question 5

Lighly touching one’s skin with a pen will result to?

Answer 5

change in the membrane potential depending on the stimulus intensity

Question 6

What cell structure is the site of LIPID and STEROID synthesis?

Answer 6

SER (smooth endoplasmic reticulum)

Question 7

True about action potential:

Answer 7

Action is inevitable
Follows all or none principle
It is propagated with the same size and shape along the length of the axon

Question 8

This change from RMP occurs when the membrane potential becomes less negative approaching zero mV

Answer 8

Depolarization

Question 9

The resting membrane potential in a NEURON is -70mV because

Answer 9

the Na-K pump activity provides additional loss of positive charges in the cell

Question 10

It is the membrane potential wherein an action potential is inevitable

Answer 10

Threshold potential

Question 11

It is NOT a characteristic of an ion channel:

Answer 11

Saturation kinetics

Question 12

During the repolarization phase, there is an increase in

Answer 12

potassium efflux

Question 13

what type of transport process is involve when sodium is transported into the cell in exchange for calcium?

Answer 13

secondary active transport

Question 14

which of the following statements is a characteristic of a graded potential?

Answer 14

It can undergo summation

Question 15

A state in which a stronger than the threshold stimulus is required to trigger another action potential

Answer 15

Relative refractory period

Question 16

Na-Glucose symporter exemplifies what class of membrane transport protein?

Answer 16

Solute carrier

Question 17

I. RMP of nerve fiber: -70mV
II. stimulus applied which brought the membrane potential to -50mV
What happens next?

Answer 17

Influx of sodium into the nerve fiber

Question 18

The following are the factors that increase the rate of diffusion across the cell membrane EXCEPT:

Answer 18

High viscosity medium

Question 19

A semi permeable membrane (selectively permeable to water and less permeable to NaCl) is placed between Solution A containing 150mm’L of NaCL and solution B containing 300 mmol/L of NaCl. What is th expected finding in this experiment?

Answer 19

There will be movement of water from Solution B to A.

Question 20

The driving force for movement of water between the ECF and the ICF is

Answer 20

Osmotic pressure gradient

Question 21

The sound waves heard by our ears first activate which channels?

Answer 21

Mechanically gated channels

Question 22

This is the potential difference generated across membrane because of a concentration difference of an ion

Answer 22

Diffusion potential

Question 23

The transport of water across the membrane required which transport protein?

Answer 23

Aquaporins

Question 24

Which of the following chemical composition forms the cytoskeleton of the cellular organelles?

Answer 24

proteins

Question 25

Which of the following provides low resistance connection between cells?

Answer 25

Gap junction

Question 26

Which of the ff. events occurs during depolarization?

Answer 26

Both Na+ activation and inactivation gates are open while K+ gated channel remains closed

Question 27

Increased conductance to sodium ions will result to

Answer 27

depolarization

Question 28

Which of the following is TRUE about local potential?

Answer 28

Undergoes summation

Question 29

How much will be the estimated total body of water of a 60-kg man have?

Answer 29

36 L

Question 30

The polarized state of a cell membrane is due to

Answer 30

potassium leak channels