Charge from depolarization along the axon reaches the axon terminal, but there is a lack of neurotransmitter release. Which of the following would cause this? Group of answer choices A. Lack of Na+ in the synaptic cleft B. Lack of Ca2+ in the synaptic cleft C. Reduced amount of K+ at the axon terminal D. Lack of voltage-gated sodium channels in the axon terminal

Using cable theory to describe axon conduction would tell us a. the larger the diameter of the axon the faster the propagation of the action potential b. the larger the diameter of the axon the slower the propagation of the action potential c. the smaller the diameter of the axon the faster the propagation of the action potential d. that having big axons is of no benefit and only takes up a lot of space e. the nervous system mainly has small axons because they are much faster than large ones

When a neuron reaches threshold voltage, all voltage-gated channels are triggered to make conformational changes. The order in which this happens comes down to the timing/speed/kinetics of the different gates on the channels. Put the following events in the order they occur after a neuron reaches threshold voltage. 1. Voltage-gated K+ channels finish closing their gate. 2. Voltage-gated Na+ channels open their activation gate, increasing Na+ permeability. 3. Voltage-gated Na+ channels close their inactivation gates, reducing Na+ permeability. 4. Voltage-gated K+ channels open their gate, increasing K+ permeability. 5. Voltage-gated Na+ channels reset to their original conformation.

If a neuron is stimulated simultaneously by 2 stimuli at its dendrites (one generates a very large hyperpolarizing potential and the other generates a very small depolarizing potential). What would happen to this neuron? Group of answer choices The summation of these two graded potentials will generate an action potential and this action potential will travel down the axon. Summation of these two graded potentials will cause the membrane potential at the axon hillock to be more negative. These graded potentials will bring the resting membrane potential to 0 mV. These graded potentials with opposite polarity would therefore generate two action potentials and they will travel along this neuron in opposite direction.

Neurotransmitters: a. Can only inhibit the postsynaptic cell b. Can be part of a process that regulates transcription and translation in the postsynaptic cell с. Are bound to their receptors forever, until the receptor is degraded and recycled. d. Can exit the presynaptic cell without assistance. e. Can only excite the postsynaptic cell Clathrin: Is embedded in the cell membrane of the synaptic terminal. a. b. Degrades vesicles for recycling and return to the axon hillock с. Mediates ALL endocytosis in the body, including the formation of vesicles in the synapse. d. Forms a coat of octagonal proteins. e. Helps the vesicle leave the pre-synaptic cell, and fuse to the membrane of the post-synaptic cell

Which of the following neuronal changes is associated with short term synaptic strength? O a. Changes in the size of neural spines o b. Changes in the shape of neural spines с. Increased production of neurotransmitter vesicles in the presynaptic cell o d. Increased buildup of Ca²+ in the terminal knob of the presynaptic axon О е. Increased expression of postsynaptic neurotransmitter receptors

Neuron 1 fires an action potential, releasing neurotransmitters to neuron 2.  However, neuron 2 does not fire an action potential itself.  Use your understanding of neuronal signaling to identify and explain two possible reasons for this observation.

Organophosphate pesticides inhibit the action of acetylcholinesterase. What effect does this have in the cell?     Select one: a. It prevents synthesis of ACh in the presynaptic terminal causing less neurotransmitter release b. It prevents breakdown of ACh in the synapse causing increased activity at the postsynaptic cell c. It prevents reuptake of ACh into the presynaptic terminal causing increased activity at the postsynaptic cell d. It prevents binding of ACh on the postsynaptic cell causing less activity e. It prevents reuptake of ACh into the presynaptic terminal causing less neurotransmitter synthesis.

When an impulse arrives at the synapse, the synaptic vesicles open and release neurotransmitters into the cleft within a thousandth of a second. Within another ten thousandth of a second, these molecules have diffused across the cleft and bound to receptor sites in the effector cell. In what two ways is transmission across a synapse terminated so that the neuron’s signal is concluded?

If an excitatory synapse and inhibitory synapse generate postsynaptic potentials on the same neuron what can happen? a. The generated potentials will sum up to make a larger postsynaptic potential. b. Nothing will happen, because inhibitory neurons will not form synapses on the same neurons as excitatory neurons. c. The postsynaptic potential generated by the inhibitory synapse will shunt the excitatory synapse, leading to a reduction in the postsynaptic potential. d. None of the above