Physiology Unit 2: Module 9 - Synapses

Excessive alcohol intake can cause difficulty maintaining posture and coordinating body movements. This is likely due to alcohol's stimulatory effect on _________ releasing neurons

Identify the FALSE statement

The trigger zone is the integrating center of the neuron

IPSPs depolarize the membrane

EPSPs that reach threshold can initiate an action potential

Long-term depression signals decrease the number of synapses

You are studying a disease in which inhibition of sensory neurons is diminished, leading to more dramatic sensory sensations than are appropriate for stimulus strength. For example, when a person with this disease listens to a person talking in a normal voice, it sounds like they are yelling. Which neurotransmitter might be expressed at lower levels in this disease compared to a healthy individual?

In clinical trials, scientists discover that use of drug X results in a decrease in norepinephrine signaling. In the process of making a list of possible mechanisms of this drug to test, which of the following is NOT a plausible explanation for the effects of drug X?

X inhibits synthesis of norepinephrine at the axon terminal

X blocks reuptake of norepinephrine by the terminal

X inhibits norepinephrine release from the terminal

X is an adrenergic receptor antagonist

X stimulates the catabolism of norepinephrine

Which of the following is NOT part of the mechanism leading to neurotransmission release?

Neurotransmitters diffuse across synaptic cleft

Calcium entry triggers exocytosis of neurotransmitters

Depolarization opens voltage-gated Ca++ channels

Neurotransmitters enter reuptake channels

Action potential depolarizes the axon terminal

When acetylcholine binds to this receptor(s), it causes the cell to depolarize.

Nicotinic receptors are expressed on skeletal muscle cells. Which of the following would likely be a side-effect of the use of nicotine, an agonist for those receptors?

Muscle cell twitches (contractions)

Muscle relaxation

Drowsiness

Muscle paralysis

Which of the following is true? Choose all that apply.

Magnesium leads to exocytosis at levels higher than the control

High levels of calcium along with magnesium lead to exocytosis but at levels lower than low calcium

High levels of calcium along with magnesium lead to exocytosis but at levels lower than the control

Low levels of calcium lead to exocytosis but at levels lower than the control

Choose all statements that apply to the data below.

A stimulus of 20 mV always results in an action potential

Increasing the stimulus voltage but maintaining the stimulus duration results in a stronger signal

Maintaining the stimulus voltage but decreasing the stimulus duration results in a stronger signal

An action potential frequency of 60 Hz is stronger than 33 Hz

Maintaining the stimulus voltage but increasing the stimulus duration results in a stronger signal

Which of the following is a possible mechanistic explanation for treatment "Mg2+and high Ca2+". Choose all that apply.

Mg2+ may block action potential from arriving to the axon terminal

Mg2+ may bind and block Ca2+ voltage gated channels so Ca2+ cannot enter

Mg2+ may bind and block Ca2+ voltage gated channels so Ca2+ cannot exit

Mg2+ may bind and block Ca2+ binding sites on snare proteins

Which of the following explains the data for the treatment "no Ca2+"

When calcium binds, exocytosis occurs

No calcium to bind snare proteins to pull vesicle to plasma membrane leads to no exocytosis

No calcium to bind to receptors leads to no exocytosis

No calcium = no exocytosis

How do different action potential frequencies code for different signal strengths in the post-synaptic neuron?

� frequency action potentials → ↑ serotonin release → ↑ neurotransmitter binding to receptor → ↑ hyperpolarization in post-synaptic neuron

↑ frequency action potentials → ↑ serotonin release → ↑ neurotransmitter binding to receptor → ↑ repolarization in post-synaptic neuron

� frequency action potentials → ↑ serotonin release → ↑ neurotransmitter binding to receptor → ↑ depolarization in post-synaptic neuron

� frequency action potentials → ↑ serotonin release → ↑ neurotransmitter binding to receptor → ↓ depolarization in post-synaptic neuron

Physiology Unit 2: Module 9 - Synapses

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