EXCITABLE TISSUE
1. The Resting Membrane Potential:
a) Is a property of all cells
b) Depends primarily on sodium influx
c) Magnitude is the same in all excitable cells
d) Is mostly due to Gibbs-Donnan effect
e) Drops immediately to zero if sodium-potassium pump is blocked
2. Active transport differs from facilitated diffusion in that:
a) It requires a carrier
b) It moves substances from high to low concentration
c) It requires energy
d) It occurs through channels
e) It is the only mechanism that moves sodium across cell membranes
3. The following substances may cross cell membranes by simple passive
diffusion except:
a) Potassium
b) Sodium
c) Protein
d) Water
e) Chloride
4. The action potential in skeletal muscles
a) Usually starts in the end plate
b) Causes the release of calcium from sacroplasmic reticulum
c) Has no refractory period
d) Is similar in shape to that of cardiac muscle, but takes less time
e) Is due to auto-rhythmicity of skeletal muscles
5. Contraction of skeletal muscles does not require:
a) Influx of extracellular Ca2+
b) Myosin
c) Troponin
d) An action potential
e) Actin
6. In chemical synapses, the following are needed for proper function except:
a) A neurotransmitter from the presynaptic neuron
b) A receptor for the neurotransmitter in the postsynaptic neuron
c) A mechanism for the removal of the transmitter
d) Ca2+ channels in the synaptic knob
e) Ca2+ channels in the post-synaptic neuron
, 7. Smooth muscle is similar to skeletal muscle in that:
a) It forms latch bridges
b) It has myosin
c) It has troponin
d) An action potential is essential for starting contraction
e) Is the property of plasticity
8. When an axon is described with one of the following it means the speed of the
transmission is slow except:
a) Small in diameter
b) Unmyelinated
c) Demyelinated
d) Type C
e) In the peripheral nervous system not CNS
9. In order to initiate skeletal muscle contraction Ca2+ should bind to:
a) Myosin
b) Tropomyosin
c) The Z-Line
d) Actin
e) Troponin
10. The resting membrane potential is generated by the following factors:
a) Selective permeability of cell membrane to K+
b) The high concentration of Na+ in the ECF
c) The high concentration of phosphates in the cell nucleus
d) The low concentration of Ca2+ inside the cells
e) Free movement of bicarbonate across the cell membrane
11. The following is not one of the functions of proteins in the cell membrane:
a) Assists endocytosis
b) Receptor for neurotransmitters
c) Adhesion between cells
d) Enzyme
e) Hormone
12. The following is true about changes in cell membrane potential:
a) The action potential occurs in all tissues
b) Local potentials do not occur in excitable tissues
c) Local potentials are all-or-none
d) Active transport of Na+ is responsible for depolarization
e) Repolarization takes longer than depolarization
13. The following is true about the action potential:
a) An external stimulus is needed for its initiation in the SA node
b) The depolarization phase is due to Ca2+ influx in cardiac muscle property
c) Its duration in cardiac muscle is similar to skeletal muscle
d) It is essential for initiation of contraction in all types of muscles
e) K+ efflux is always the primary cause of repolarization
1. The Resting Membrane Potential:
a) Is a property of all cells
b) Depends primarily on sodium influx
c) Magnitude is the same in all excitable cells
d) Is mostly due to Gibbs-Donnan effect
e) Drops immediately to zero if sodium-potassium pump is blocked
2. Active transport differs from facilitated diffusion in that:
a) It requires a carrier
b) It moves substances from high to low concentration
c) It requires energy
d) It occurs through channels
e) It is the only mechanism that moves sodium across cell membranes
3. The following substances may cross cell membranes by simple passive
diffusion except:
a) Potassium
b) Sodium
c) Protein
d) Water
e) Chloride
4. The action potential in skeletal muscles
a) Usually starts in the end plate
b) Causes the release of calcium from sacroplasmic reticulum
c) Has no refractory period
d) Is similar in shape to that of cardiac muscle, but takes less time
e) Is due to auto-rhythmicity of skeletal muscles
5. Contraction of skeletal muscles does not require:
a) Influx of extracellular Ca2+
b) Myosin
c) Troponin
d) An action potential
e) Actin
6. In chemical synapses, the following are needed for proper function except:
a) A neurotransmitter from the presynaptic neuron
b) A receptor for the neurotransmitter in the postsynaptic neuron
c) A mechanism for the removal of the transmitter
d) Ca2+ channels in the synaptic knob
e) Ca2+ channels in the post-synaptic neuron
, 7. Smooth muscle is similar to skeletal muscle in that:
a) It forms latch bridges
b) It has myosin
c) It has troponin
d) An action potential is essential for starting contraction
e) Is the property of plasticity
8. When an axon is described with one of the following it means the speed of the
transmission is slow except:
a) Small in diameter
b) Unmyelinated
c) Demyelinated
d) Type C
e) In the peripheral nervous system not CNS
9. In order to initiate skeletal muscle contraction Ca2+ should bind to:
a) Myosin
b) Tropomyosin
c) The Z-Line
d) Actin
e) Troponin
10. The resting membrane potential is generated by the following factors:
a) Selective permeability of cell membrane to K+
b) The high concentration of Na+ in the ECF
c) The high concentration of phosphates in the cell nucleus
d) The low concentration of Ca2+ inside the cells
e) Free movement of bicarbonate across the cell membrane
11. The following is not one of the functions of proteins in the cell membrane:
a) Assists endocytosis
b) Receptor for neurotransmitters
c) Adhesion between cells
d) Enzyme
e) Hormone
12. The following is true about changes in cell membrane potential:
a) The action potential occurs in all tissues
b) Local potentials do not occur in excitable tissues
c) Local potentials are all-or-none
d) Active transport of Na+ is responsible for depolarization
e) Repolarization takes longer than depolarization
13. The following is true about the action potential:
a) An external stimulus is needed for its initiation in the SA node
b) The depolarization phase is due to Ca2+ influx in cardiac muscle property
c) Its duration in cardiac muscle is similar to skeletal muscle
d) It is essential for initiation of contraction in all types of muscles
e) K+ efflux is always the primary cause of repolarization
