Can someone please help me with the following questions?
1. Excitability is the ability to transit nerve impulses to other neurons. (Points : 1)
True
False
2. When a neuron is stimulated, the membrane becomes more permeable to Na+ ions, which diffuse into the cell, causing ___. (Points : 1)
depolarization
hyperpolarization
repolarization
3. As an action potential progresses, the permeability to Na+ decreases and the permeability to ____ increases. (Points : 1)
Ca2+
K+
Na+
4. The period of time when the neuron is totally insensitive to further stimulation and cannot generate another action potential is the ____. (Points : 1)
absolute refractory period
membrane potential
repolarization
threshold
5. The resting membrane potential is the potential difference (electrical charge difference) between the inside of the cell and the outside of the cell across the cell membrane (Points : 1)
True
False
6. What is the approximate concentration of K+ inside a typical cell? (Points : 1)
150 mM
5 mM
10 mM
15 mM
7. What is the approximate concentration of K+ outside a typical cell? (Points : 1)
150 mM
5 mM
10 mM
15 mM
8. What is the approximate concentration of Na+ inside a typical cell? (Points : 1)
150 mM
5 mM
10 mM
15 mM
9. What is the approximate concentration of Na+ outside a typical cell? (Points : 1)
150 mM
5 mM
10 mM
15 mM
10. In Activity 1, the intracellular voltage of the resting (control) neuron is _____ compared to the extracellular voltage. (Points : 1)
0
-70
-40
+ 10
11. Having a negative intracellular charge means that there are more negative charges than there are positive charges just inside the neuronal cell membrane. (Points : 1)
True
False
12. Which of the following caused a change in membrane potential from -70 (in the control) to -40 in the cell body. (Points : 1)
an increase in extracellular K+
a decrease in extracellular K+
an increase in extracellular Na+
a decrease in extracellular Na+
13. The end of the axon where it contacts the target is called the _____. (Points : 1)
cell body
myelin sheath
axon terminal
nucleus
14. Neurotransmitter is released into the synaptic gap by ___. (Points : 1)
exocytosis
voltage-gated neurotransmitter channels
muscle contraction
the postsynaptic membrane of the target cell
15. Exocytosis of neurotransmitter from the axon terminal is triggered by an increase of in the intracellular concentration of ___. (Points : 2)
Na+
K+
Ca2+
none of the above
16. Neurotransmitter that has been released into the synpatic gap reaches the target by ___. (Points : 1)
exocytosis
diffusion
muscle contraction
conduction down the axon
17. At the target, neurotransmitter _____. (Points : 1)
binds to receptor proteins
causes membrane channels to open or close
causes a change in membrane potential
does all of the above
Quick Reply
