Question

MULTIPLE CHOICE:

1. Working to maintain resting levels in the neuron, sodium-potassium pumps use ________% of
              the brain’s total energy.
              a. 10-15                                        c. 20-40
              b. 18-22                                        d. 35-50

2. When calcium flows into the terminal, it causes
              a. the vesicles to fuse with cell membranes to release neurotransmitters into the synapse.
              b. magnesium to move to the post-synaptic neuron’s channels.
              c. the hillock to interpret an action potential.
              d. all of the above to happen.
3. Because potassium channels are a little slow to close,
              a. the cell becomes hyperpolarized         c. the brain gets confused
              b. neurons become malnourished           d. all of the responses are correct

4. Which of the following is NOT a facilitated end-result of secondary messengers?
              a. synaptogenesis                                                    c. short-term memory
              b. neurotransmitter synthesis and release              d. all of the responses are correct
5. Which of the following regarding saltatory conduction is true?
              a. For it to occur, there must be an excessive amount of sodium in the vesicles.
              b. The action potential is transmitted faster when myelin is present because of the process of
                           saltatory conduction.
              c. It is a process that is imperative for astrocytes to form.
              d. All of the responses are correct.
6.   When more glutamate is present, the AMPA channel
              a. remains open longer                                           c. is unaffected
              b. remains open a shorter period of time              d. often is corrupted

Answer 1

1. The energy expenditure for Na,K-ATPase to maintain normal resting membrane potential is calculated about 50% of total brain energy consumption

Answer is d. 35-50

2. When Ca2+ flows into the nerve terminals, Synaptic vesicle (Contain neurotransmitters) in the terminal moves towards the cell membrane and fuse with that membrane causes releases of neurotransmitters known as exocytosis

Answer is   a. the vesicles to fuse with cell membranes to release neurotransmitters into the synapse.

3. Repolarization occur as the result of outflow of K+ ions  when voltage gated potassium channels open. After complete repolarization. K+ channels remains open and K+ ion outflow continue result in hyperpolarization

Answer is a. the cell becomes hyperpolarized   

4. second messengers are intracellular signaling molecule that are generated in response to a fist messenger such as hormone. Example of second messenger is cyclicAMP, GMP, inositol trisphosphate. cAMP (cyclic AMP)- involved in the short-term memory.

Answer is  c. short-term memory

5. A special mode of transmission of impulses long the myelinated axone is called  saltatory conduction. This conduction affected by amount of myelination, diameter of axon, distribution of ion channels.

Answer is b. The action potential is transmitted faster when myelin is present because of the process of saltatory conduction.