week 2 preclass activity quizz

 

Question 2

0 / 1 pts

When I teach this in person, I like to make an analogy between pacemaker cells, contractile cells, and the autonomic nervous system (ANS). Remember that the ANS is divided into sympathetic (speeds up heart rate) and parasympathetic (slows down heart rate).

 

Consider how lights can be turned on/off and that some have a dimmer switch:

 

I would argue that each component: pacemaker, contractile cells and autonomic nervous system match the way this lighting system works. Check your understanding by matching the terms below.

Correct!

Pacemakers are autorhythmic and determine when contractile cells will depolarize.

 

               Light switch on/off             

Correct!

ANS can determine how fast or slow pacemaker and contractile cells depolarize and therefore speed up/slow down heart rate.

 

               Dimmer switch (controls how bright/dim lights are)             

Correct!

Contractile cells are THE cardiac muscle cells that generate contractions (pumping/beating) of the heart. They follow the pace set by pacemakers & ANS.

 

               The actual light (how bright or on/off)             

How are contractile and pacemaker cells connected? Select all

Correct!

  

They have continuous channels and share ions, forming a network of cells called a syncytium.

 

  

There are two syncytia: atrial and ventricular. This explains why the atria contract at once and the ventricles contract second.

 

You Answered

  

If connections between pacemaker & contractile cells are most similar to a chemical synapse.

 

Correct Answer

  

If connections between pacemaker & contractile cells are most similar to an electrical synapse.

 

How does the heart pump? How does it know when to beat?

  

Contractile cells set the pace/rhythm of beats. Autorhythmic cells cause cardiac muscle contractions

 

Correct!

  

Autorhythmic cells set the pace/rhythm of beats. Contractile cells cause cardiac muscle contractions

 

Week 3 practice question

 Question 1

1 / 1 pts

Chlorpromazine (marketed under brand names Thorazine and Largactil) is a drug used to treat psychotic disorders such as schizophrenia or manic-depression in adults. Chlorpromazine was developed in the 1950s and its introduction as the first antipsychotic on the market has been labeled as one of the great advances in the history of psychiatry.

Chlorpromazine blocks postsynaptic receptors for several different neurotransmitters, such as dopamine and serotonin. Predict the effect of chlorpromazine on synaptic transmission by selecting all of the steps it will directly inhibit in the picture below.

  

5

 

  

4

 

  

1

 

  

2

 

  

3

 

 

Question 2

1 / 1 pts

Some neurotransmitter receptors are ion channels that open when the neurotransmitter binds to them. Those receptors are called:

  

mechanically gated ion channels.

 

  

light-gated ion channels.

 

  

ligand-gated ion channels.

 

  

voltage-gated ion channels.

 

 

Question 3

1 / 1 pts

Funnel-web spiders are found in southeast Australia, around Sydney. Others are found in Europe, New Zealand, and Chile. They are not native to the United States, although some people may keep them as exotic pets.

Their bites are very painful and dangerous. They have been known to cause serious symptoms, such as agitation, confusion, numbness of mouth and lips, and even coma and death.

Funnel-web spider venom is a neurotoxin that blocks gated calcium channels. Its effect would be a/an:

  

increased neurotransmitter release.

 

  

decreased neurotransmitter release.

 

  

decreased production of neurotransmitter.

 

  

increased production of neurotransmitter.

 

 

Question 4

1 / 1 pts

Identify the ion that would move through the channel to produce an IPSP.

Ions 1-3 are in the extracellular fluid (blue background),  ions 4-6 are in the cytosol (yellow background). Figure out which ion and which direction it would flow based on what you know about concentration gradients for each ion.

  

Na+

 

  

Ca2+

 

  

K+

 

 

Question 5

1 / 1 pts

One type of channel involved in generating postsynaptic potentials at a chemical synapse is the:

  

ligand-gated ion channel.

 

  

light-gated ion channel.

 

  

mechanically gated ion channel.

 

  

voltage-gated ion channel.

 

 

Question 6

1 / 1 pts

Selective serotonin reuptake inhibitors (or SSRIs), such as Prozac, Celexa, Lexapro, Paxil, and Zoloft, are a class of drugs used to treat mood disorders such as depression and anxiety. They inhibit the transporter responsible for serotonin reuptake into the presynaptic neuron. What is the effect of the SSRIs on the serotonin concentration in the synaptic cleft?

  

The serotonin concentration in the synaptic cleft will increase.

Correct. When reuptake is inhibited, more serotonin stays in the cleft longer and is available to stimulate postsynaptic neurons. Since mood disorders often correlate with reduced serotonin availability and receptor stimulation, SSRIs are effective in helping patients who suffer from these disorders.

  

The serotonin concentration in the synaptic cleft will decrease.

 

Question 7

1 / 1 pts

Which of the following does NOT happen to neurotransmitters during synaptic transmission termination?

  

Diffusion away from synaptic cleft

 

  

Reuptake into presynaptic neuron

 

  

Uptake into postsynaptic neuron

 

  

Degradation by enzymes

 

 

Question 8

1 / 1 pts

Use what you learned during the Lecture 3 handout.

Cocaine is a powerfully addictive stimulant drug made from the leaves of the coca plant native to South America. As a street drug, cocaine looks like a fine, white, crystal powder or it is processed to a make rock crystal.

Cocaine acts as a dopamine reuptake inhibitor. Therefore, cocaine will:

  

decrease dopamine in the synaptic cleft.

 

  

increase dopamine receptor stimulation.

 

Correct. Less reuptake means more dopamine remains in the cleft and is available to stimulate dopamine receptors.

  

decrease dopamine inside the postsynaptic neuron.

 

  

increase dopamine in the axon terminal.

 

 

Question 9

1 / 1 pts

During the absolute refractory period, the axon membrane:

  

is unable to generate an action potential.

 

  

contains open voltage-gated Na+ channels.

  

is at –90 mV.

 

  

is more responsive to depolarization.

 

 

Question 10

1 / 1 pts

The refractory period of an action potential...

  

Allows bidirectional flow of the action potential

 

  

Is not a component of every action potential

 

  

Prevents flow of action potential toward cell body

 

  

Has no effect on direction of action potential propagation

 

 

Question 11

1 / 1 pts

The faster, more efficient way of propagating an action potential is:

  

unmyelinated conduction.

 

  

saltatory conduction.

 

  

disruptive conduction.

 

  

continuous conduction.

 

 

Question 12

1 / 1 pts

The threshold potential is best defined as the potential at which...

  

Voltage-gated potassium channels open

 

  

Voltage-gated potassium channels close

 

  

Voltage-gated sodium channels open

 

  

Chemically gated sodium channels open

 

 

Question 13

1 / 1 pts

Action potentials self-propagate because...

  

ATP is always available to drive the action potential

 

  

Each action potential triggers another in the next section of axon

 

  

They are a form of negative feedback

 

  

Neurotransmitter is released constantly