Synaptic Transmission Guiding Questions

 Synaptic Transmission Guiding Questions

Describe the sequence of events that occurs when glutamate is released from the presynaptic cell. How do these events lead to LTP?

Describe the structure of the synapse of the neuromuscular junction.

What is the neurotransmitter released from a somatic motor neuron?

What is the receptor on the muscle cell? Does triggering this receptor with neurotransmitter trigger a fast response or a slow response?

Describe the sequence of events that occurs when an action potential reaches the axon terminal of a somatic motor neuron.

How is synaptic transmission terminated at a neuromuscular junction?

What is AChE and what does it do at the synaptic cleft?

What is an agonist and how does it affect synaptic transmission? Give examples of both direct and indirect agonists.

What is an antagonist and how does it affect synaptic transmission? Give examples of both direct and indirect antagonist

Explain how GABA work to inhibit post-synaptic cell response.

How would blocking GABA receptors affect response in the post-synaptic cell?

Hint, remember our in-class handout!

Make a list of all of the ion channels we have discussed. Make sure you indicate where you find the channel, how it is gated, which way ions will travel through it and their effect on membrane potential and when it is used.

Make a list of all of the neurotransmitter-receptor pairs we have discussed. Make sure you indicate where the neurotransmitters are used and how they are regulated

Hint, we did a lot of this in our in-class handouts!

 

Peripheral Nervous System Guiding Questions

Describe the organization of the nervous system.

Be sure to use the following terms: efferent neurons, afferent neurons, sensory receptors, autonomic neurons, somatic motor neurons, parasympathetic neurons, sympathetic neurons, somatic motor neurons, skeletal muscles, central nervous system, peripheral nervous system.

What does the somatic motor division of the efferent nervous system control?

Describe the structure, target, neurotransmitter and receptor and enzyme used in the somatic motor division.

What are the two divisions of the autonomic nervous system?

What are the targets of the autonomic nervous system?

How are pre and postganglionic neurons similar and different in the sympathetic vs parasympathetic divisions?

Describe how the two divisions of the autonomic nervous system maintain homeostasis through antagonistic control.

Give several examples of antagonistic control carried out by the autonomic nervous system.

Describe how the preganglionic neuron and the postganglionic neurons are arranged in the sympathetic and parasympathetic systems.

What neurotransmitter-receptor pair is used in the autonomic ganglion of BOTH divisions of the autonomic nervous system?

How are the postganglionic autonomic synapses similar and different than the synapses in the neuromuscular junction?

Hint, a lot of this work is summarized by your in-class handout!

In the sympathetic division, what neurotransmitter-receptor pair is used in the ganglion? What about at the postganglionic synapse?

Give several examples of how the parasympathetic system affects different tissues (for example, how does it affect heart rate, salivation, rate of digestion, airways)

Describe how different types of adrenergic receptors can cause different responses to the same neurotransmitter.

As an example, explain how this works to modulate the diameter of arteries in the digestive system and blood vessels in the skeletal muscles during a systemic sympathetic response.

Hint, this is summarized in your in-class handout!

You can review the adrenal medulla material (it will be relevant in 40C as well), but note I won’t ask you any questions about it!

In the parasympathetic division, what neurotransmitter-receptor pair is used in the ganglion? What about at the postganglionic synapse?

Compare and contrast nicotinic receptors and muscarinic receptors.

Give several examples of how the parasympathetic system affects different tissues (for example, how does it affect heart rate, salivation, rate of digestion, airways)

Again, this is summarized by our in-class activity!

Multiple Sclerosis and the Myelin Sheath

2-Minute Neuroscience: Synaptic Transmission

2-Minute Neuroscience: Synaptic Transmission

What is the trigger for neurotransmitter release from a synapse?

 Copilot Using the web

The trigger for neurotransmitter release from a synapse involves a series of events that occur at the chemical synapse. Let me break it down for you:

Nerve Action Potential: When an action potential (a rapid change in voltage) propagates down the axon of a presynaptic neuron, it depolarizes the synaptic terminal.

Voltage-Gated Calcium Channels: The depolarization caused by the action potential opens voltage-gated Ca2+ channels in the presynaptic terminal, allowing calcium ions (Ca2+) to enter.

Exocytosis of Vesicles: The influx of calcium serves as the signal to trigger exocytosis of presynaptic vesicles. These vesicles contain neurotransmitters (such as acetylcholine, ACh).

Diffusion of Neurotransmitter: The released neurotransmitter (ACh) diffuses across the narrow synaptic cleft and binds to nicotinic ACh receptors on the postsynaptic cell membrane.

Postsynaptic Response: Binding of ACh to its receptors opens non-selective cation channels (allowing both K+ and Na+ ions to flow), leading to a local depolarization called the end-plate potential. If the depolarization reaches firing threshold, it triggers an action potential in the postsynaptic cell, which can lead to muscle contraction or other responses12.

In summary, the increase in internal Ca2+ is a crucial signal that initiates neurotransmitter release at chemical synapses. This process is conserved across all chemical synapses in the nervous system1. If you have any more questions or need further clarification, feel free to ask! 😊

Learn more

1

uw.pressbooks.pub

2

khanacademy.org

3

britannica.com

4

openbooks.lib.msu.edu

+2 more

Answer from this page instead

What are some common neurotransmitters?

How does synaptic plasticity work?

Tell me more about the postsynaptic response.

Week 3 guided question

• What types of neurotransmitters are generally inhibitory?

GABA 

• What types are generally excitatory?

Glutamate 

• What is the trigger for neurotransmitter release from a synapse?

Both EPSP and IPSP caused neurotransmitters release by presynapse.

• Outline/draw the steps of synaptic transmission.

• How are neurotransmitters cleared from the synaptic cleft?

 (3 ways!)

The Difference Between Agonists vs. Antagonists

Neuron #1 sends an IPSP that changes the membrane -30mV Neuron #2 sends an EPSP that changes the membrane +10mV Does Neuron #3 send an action potential down its axon?

 

Now pull out your notes for spatial vs. temporal summation. Then check out the synapse below. If Neuron #1 and 2 trigger graded potentials of the same amplitude at the same time in neuron #3, does Neuron #3 send an action potential?

 

How are EPSPs (excitatory post-synaptic potentials) and IPSPs (inhibitory post synaptic potentials) associated with hyperpolarization or depolarization?

 How are EPSPs (excitatory post-synaptic potentials) and IPSPs (inhibitory post synaptic potentials) associated with hyperpolarization or depolarization?

  EPSPs are triggered by depolarizing graded potentials 

  EPSPs are triggered by hyperpolarizing graded potentials 

  IPSPs are triggered by depolarizing graded potentials 

  IPSPs are triggered by hyperpolarizing graded potentials 

reference video https://www.youtube.com/watch?v=KQOM_sXBtbw

Depolarizing local potentials are caused by Na+ influx via:

 Depolarizing local potentials are caused by Na+ influx via:

  Na+/K+ pumps. 

  Na+/Cl– symporters. 

  leak channels. 

  gated ion channels. 

reference insight 

Hyperpolarizing graded potentials can be caused by: (choose all the correct answers)

 As you learned, graded potentials can be hyperpolarizing or depolarizing. 

The ions that flow in @ the dendrites/soma will diffuse outwards in all directions.

 Some will end up at the axon hillock where they will either trigger an action potential (A.P.) or not.

Consider:

An A.P. is triggered when a threshold potential of -55mV is reached at the hillock.

Hyperpolarizing graded potentials would drive the membrane more negative than -70mV

Depolarizing graded potentials would drive the membrane more positive than -70mV

Review what types of ion channels can be opened @ dendrites/soma (last week's lecture)

Hyperpolarizing graded potentials can be caused by: (choose all the correct answers)

1.   Opening of photo-gated Cl- channels 
2.   Opening of ligand-gated Ca2+ channels 
3.   Closing of voltage-gated Na+ channels 
4.   Opening of mechanically-gated K+ channel

reference key insight 

Temporal vs. Spatial Summation

week one revised

 

Resting Membrane Potential (RMP):

 copy from Copilot Using the web

Certainly! Let’s delve into the fascinating world of Na+ and K+ leak channels and their role in the resting membrane potential of cells.

Describe the mechanism of Na+ and K+ leak channels. How do they contribute to the resting membrane potential of a cell? How do they contribute to membrane permeability?

Resting Membrane Potential (RMP):

The resting membrane potential refers to the voltage difference across the cell membrane when a neuron is not actively transmitting signals.

In most resting neurons, the potential difference across the membrane ranges from about -30 mV to -90 mV, with the inside of the cell being more negative than the outside1.

This resting potential is essential for maintaining cell function and preparing the neuron for action potentials.

Na+ and K+ Leak Channels:

Leak channels are integral membrane proteins that allow ions (such as Na+ and K+) to move across the cell membrane passively, without requiring energy.

Specifically, Na+ and K+ leak channels contribute significantly to the resting membrane potential:

K+ Leak Channels:

These channels allow potassium ions (K+) to slowly move out of the cell.

Since the membrane is much more permeable to K+ than to Na+, the resting potential is close to the equilibrium potential of K+ (the potential that would be generated by K+ if it were the only ion in the system).

Na+ Leak Channels:

These channels allow sodium ions (Na+) to slowly move into the cell.

Although Na+ leak channels contribute less to the resting potential than K+ leak channels, they still play a role in maintaining the overall balance of ions.

Contribution to Membrane Permeability:

The resting potential is determined by both the concentration gradients of ions across the membrane and the membrane permeability to each type of ion.

Ions move down their gradients via channels, leading to a separation of charge that creates the resting potential.

The Na+/K+ pump (Na+/K±ATPase) also helps maintain ion concentration gradients by actively pumping 3 Na+ ions out of the cell and allowing 2 K+ ions to move in2.

Overall, the balance between leak channels, ion pumps, and concentration gradients ensures the stability of the resting membrane potential.

In summary, Na+ and K+ leak channels contribute to the resting membrane potential by allowing ions to move passively across the cell membrane, maintaining the delicate balance necessary for cellular function. 🧪🔬

For further exploration, you might find these resources helpful:

Khan Academy: Membrane Potential

Anatomy & Physiology: The Action Potential3

Feel free to ask if you have any more questions! 😊

Learn more

1

khanacademy.org

Usingthe web

Certainly! Let’s delve into the fascinating world of Na+ and K+ leak channels and their role in the resting membrane potential of cells.

1. Resting Membrane Potential (RMP):

   • The resting membrane potential refers to the voltage difference across the cell membrane when a neuron is not actively transmitting signals.
   • In most resting neurons, the potential difference across the membrane ranges from about -30 mV to -90 mV, with the inside of the cell being more negative than the outside1.
   • This resting potential is essential for maintaining cell function and preparing the neuron for action potentials.

2. Na+ and K+ Leak Channels:

   • Leak channels are integral membrane proteins that allow ions (such as Na+ and K+) to move across the cell membrane passively, without requiring energy.
   • Specifically, Na+ and K+ leak channels contribute significantly to the resting membrane potential:
     • K+ Leak Channels:
       • These channels allow potassium ions (K+) to slowly move out of the cell.
       • Since the membrane is much more permeable to K+ than to Na+, the resting potential is close to the equilibrium potential of K+ (the potential that would be generated by K+ if it were the only ion in the system).
     • Na+ Leak Channels:
       • These channels allow sodium ions (Na+) to slowly move into the cell.
       • Although Na+ leak channels contribute less to the resting potential than K+ leak channels, they still play a role in maintaining the overall balance of ions.

3. Contribution to Membrane Permeability:

   • The resting potential is determined by both the concentration gradients of ions across the membrane and the membrane permeability to each type of ion.
   • Ions move down their gradients via channels, leading to a separation of charge that creates the resting potential.
   • The Na+/K+ pump (Na+/K±ATPase) also helps maintain ion concentration gradients by actively pumping 3 Na+ ions out of the cell and allowing 2 K+ ions to move in2.
   • Overall, the balance between leak channels, ion pumps, and concentration gradients ensures the stability of the resting membrane potential.

In summary, Na+ and K+ leak channels contribute to the resting membrane potential by allowing ions to move passively across the cell membrane, maintaining the delicate balance necessary for cellular function. 🧪🔬

For further exploration, you might find these resources helpful:

• Khan Academy: Membrane Potential
• Anatomy & Physiology: The Action Potential3

Feel free to ask if you have any more questions! 😊

Learn more

1khanacadem

axon makes a synapse a graded potential occurs in the cell membrane of a lower motor neuron

 At the level of the spinal cord at which this axon makes a synapse, a graded potential occurs in the cell membrane of a lower motor neuron. This second motor neuron is responsible for causing muscle fibers to contract.

precentral gyrus of the frontal cortex,

 A region of the cortex is specialized for sending signals down to the spinal cord for movement. The upper motor neuron is in this region, called the precentral gyrus of the frontal cortex, which has an axon that extends all the way down the spinal cord. 

Guiding question week 2

 Guiding Questions:

The resting membrane potential

 Describe the mechanism of the Na+/K+ pump and explain how it contributes to the resting membrane potential of a cell.

• 3 sodium ion bind to the Na+/K+
• ATP is hydrolyzed providing energy to change the formation
• the pump release the na outside the cell 
• two potassium ion K+ from ECF bind to the pump 
• ATP hydrolyzed restoring the pump original formation 
• the pump release the K+ inside the cell 
  
  
  

What would happen to the resting membrane potential if the Na+/K+ pump was mutated and not working?

• Loss of ion gradients , normal concentration of Na+ and K+ would be discrupted. 
• increase intracellular sodium
• decrease intracellular potassium 
• altered resting membrane potential
• hyperpolarization or depolarization

Describe several ways that intracellular fluid (ICF) differs from extracellular fluid (ECF). What ions are higher in the ICF vs ECF?

1. sodium ion higher in ECF
2. Potassium ion higer in ICF 

• ICF is the liquid inside cells, while ECF includes plasma, IF, and CSF.
• The composition of ICF and ECF differs in terms of ion concentrations, proteins, and pH.
• ICF and ECF play distinct roles in maintaining cellular function and overall body homeostasis.

Describe what a concentration gradient is and how it leads to diffusion and the establishment of a dynamic equilibrium.

 Na+/K+ Pumps help maintain osmotic equilibrium and membrane potential. Sodium and potassium ion move against concentration gradients. The sodium and potassium ion move from high concentration to low concentration. The sodium and potassium pump maintain the concentration gradient high sodium in ECF and high potassium in ICF .

 Can you identify the flow of ions in/out of cells based on concentration gradients?

Na+/K+ pump move the ion sodium in side the cell against concentration gradient from high concentration to low concentration. The pump help to maintain  the resting membrane potatial by keeping the intracellular Na+ level low . 

ECF sodium level 145 

ICF sodium level 

Describe the mechanism of Na+ and K+ leak channels. How do they contribute to the resting membrane potential of a cell? How do they contribute to membrane permeability?

What is the resting membrane potential? What voltage value is it typically for most cells in your body?

 

Altering the resting membrane potential

If the concentration gradient of K+ decreases across the cell membrane, what happens to the membrane potential?

If the cell all the sudden became permeable (think gated membrane channels opening) to K+, what would happen to membrane potential? What about Ca2+? Na+?

What is hyperpolarization vs depolarization of the membrane potential? What ion channels should be opened to cause either?

Graded Potentials

Draw and describe the structure of a neuron.

Identify each of the following structures on your drawing and describe their structures: dendrites, dendritic spines, cell body, axon, axon hillock, collateral, axon terminal, synapse, postsynaptic cell

Where are the sensory receptors located on a neuron? From where on the neuron are neurotransmitters released?

Where do graded potentials occur?

What type of stimuli causes a graded potential? How does the strength of the stimulus affect the amplitude of the graded potential?

As a graded potential travels through the cell body, they lose amplitude. Explain why. ***more on this next week

What is an EPSP? What is an IPSP? What ion channels contribute to each? Are each caused by depolarizations or hyperpolarizations?

How does an EPSP contribute to triggering an action potential? What about an IPSP?

Action Potentials***

Differentiate between graded potentials and action potentials.

Where in the neuron do action potentials occur?

How does the strength of the stimulus effect the amplitude of the action potential? Why are they all-or-none?

***more on this next week

Explain how ion permeability changes during the rising phase and falling phase of an action potential.

What is the stimulus for opening EACH of the channels used during an action potential?

What is the order of stimulus, opening and closing of all of these channels?

How is the resting membrane potential reestablished after an action potential?

Hint, we did this for our in-class activity! Can you visualize what’s happening with each of the channels?

Voltage gated Na+ channels in the axon contain two gates. What are they? How are they triggered?

What are the absolute and relative refractory periods?

How does the inactivation gate on the Na+ channel cause the absolute refractory period?

What causes the relative refractory period?

***I will update after lecture to see how much of APs we get through.

 

Hydrophobic

https://biologydictionary.net/hydrophobic/ 

Hydrophobic Definition

Hydrophobic literally means “the fear of water”. Hydrophobic molecules and surfaces repel water. Hydrophobic liquids, such as oil, will separate from water. 

Hydrophobic molecules are usually nonpolar, meaning the atoms that make the molecule do not produce a static electric field.

In polar molecules these opposite regions of electrical energy attract to water molecules. Without opposite electrical charges on the molecules, water cannot form hydrogen bonds with the molecules. The water molecules then form more hydrogen bonds with themselves and the nonpolar molecules clump together.

Hydrophilic – Molecules or substances that are attracted to water.

Hydrophilic – Molecules or substances that are attracted to water.

Polar – Molecules having static electric charges, which can interact with water.

Nonpolar – Molecules that do not have static electric charges, and are much more likely to interact with other nonpolar molecular than with water.

Lipophilic – Substances that are attracted to fat, different than hydrophobic.

Quiz

1. Some amino acids are hydrophobic, and some are hydrophilic. Hydrophobic amino acids tend to cluster together in large proteins. Why is the order of amino acids in a protein important?

A. The order determines the shape of the protein

B. It is not important, as long as all of the amino acids are present

C. Proteins are recognized by sequence of amino acids

Answer to Question #1

2. A substance is created that has very strong electrical dipoles on the molecules, but does not interact with water, due to the strong interaction it has with itself. How would you describe the molecule?

A. Hydrophilic and polar

B. Hydrophobic and nonpolar

C. Hydrophobic and polar

Answer to Question #2

3. Many reptiles, even desert-dwelling reptiles, have hydrophobic scales on the outside of their body. Why would a desert reptile want a hydrophobic covering?

A. To repel harmful sun-rays

B. The barrier also works to stop evaporation

C. To be protected from acid rain

Answer to Question #3

How Neurons Communicate

resting membrane potential quizlet practice test

https://quizlet.com/449088392/learn?funnelUUID=4be6fe79-8184-43f7-90ba-e19e526d53ac

 In an excitable cell, also permeable to Na+ and Cl-, the electrochemical gradient for Na+ causes it to move___________ the cell.

into

Excitable cells, like neurons, are more permeable to ___________ than to ___________.a.What acts as a chemical force that pushes K+out of the cell? ___________________b.What force tends to pull K+back into the cell? _________________________

K+, Na+, a. concentration gradient. b. electrical gradient

Because the neuron is permeable to Na+as well as K+, the resting membrane potential is not equal to the equilibrium potential for K+; instead, it is ___________ mV.

-90

What compensates for the movement (leakage)of Na+and K+ions? _________________________

Na+/P+ pump

What will happen to the resting membrane potential of an excitable cell if: (Write pos or neg to indicate which way the membrane potential would change.) a.extracellular fluid concentration of K+ (goes up)___________ b. ̄extracellular fluid concentration of K+ (goes down)___________ c.extracellular fluid concentration of Na+ (goes up)___________ d. ̄number of passive Na+channels (goes down) ___________ e.open voltage-gated K+channels ___________ f.open voltage-gated Na+channels___________

less negative more negative less negative less negative more negative less negative

In a cell permeable only to K+, the resting membrane potential would be called the___________________ potential for K+, which is ___________ mV.

resting membrane, -90

week one guiding question

 Guiding questions for each lecture

You can use these questions to review your lectures and check if you caught everything/understood everything discussed in lecture or your pre-class material.

Lecture 1 guiding questions

At a high level (big picture), can you answer the following?

What makes up the nervous system? (what cells)?

Neuron and glial cell 

What are the two major anatomical divisions of the nervous system?

1. Central nervous system and 
2. Peripheral nervous system

What are the divisions of the peripheral nervous system?

Somatic nervous system and Automonic nervous system

                                                                     ⛛under ANS 

                                               sympathetic nervous system and parasympathetic nervous system 

How do neurons communicate?

Neurons communicate using both electrical and chemical signals. sensory stimuli are converted to electrical signals.

Action potential signals carried along neurons. 

synapses are chemical or electrical junctions that allow electrical signals to pass from neurons to other cells. 

Can you identify the flow of ions in/out of cells based on concentration gradients?

ions in and out of the cell based on concentration gradients moving from high concentration to low concentration. 

Describe the mechanism of the Na+/K+ pump and explain how it contributes to the resting membrane potential of a cell.

Na+/K+ pump help to maintain osmotic equilibrium and membrane potential in cells.  The sodium and potassium move against the concentration gradient. Na+/K+ATPase pump maintains the gradient of higher sodium concentration in the extracellularly and higher level of potassium of potassium intracellularly.

What would happen to the resting membrane potential if the Na+/K+ pump was mutated and not working?

Additional information

 carrier proteins are typically selective for one or a few substances.

 ( example Na+ K+)

Carrier proteins can change their shape to move a target molecule from one side of the membrane to the other. 

 Channel proteins span the membrane and make hydrophilic tunnels across it, allowing their target molecules to pass through by diffusion.

Channel and carrier proteins transport material at different rates.