Lecture 16: Synaptic Transmission

Question 1

What kind of acetylcholine receptors does skeletal muscle use?

Answer 1

Nicotinic Acetylcholine Receptors

Question 2

What kind of neurotransmitter is acetylcholine?

Answer 2

Choline Ester

Question 3

What is the Quantal Hypothesis of synaptic transmission?

Answer 3

Each presynaptic vesicle (also called “quanta”) contains about 5,000 to 10,000 molecules of neurotransmitter. A more significant action potential causes more vesicles, and therefore more neurotransmitters to be released.

Question 4

What kind of effect would an excitatory post synaptic potential cause?

Answer 4

Changing of the membrane potential from its current state, closer to the threshold (more positive)

Opening of sodium channels is often how this effect is accomplished

Question 5

What is the sequence of events for a chemical synapse?

(Rather than memorize the list, review the process in your head and check it against the answer)

Answer 5

1. Neurotransmitters synthesized
2. Neurotransmitters stored in the axon terminal
3. Action potential causes a calcium channel to open, and synaptic vesicles fuse with the axon terminus to release the neurotransmitters into the synaptic gap
4. Neurotransmitters bind to the receptors
5. Post synaptic response occurs
6. Neurotransmitters are either inactivated by enzymes, cleared from the synaptic gap by diffusion, or reuptaken into the presynaptic neuron.

Question 6

What two mechanisms can inhibitory post synaptic potentials use to prevent action potentials?

Answer 6

Influx of negative ions (think Cl^-)

OR

Potassium leaving the cell

Question 7

What kind of neurotransmitter is dopamine?

Answer 7

Biogenic Amine

Question 8

Where is a good example of where you would see neurons that use electrical synaptic transmission?

Answer 8

The heart muscle

Question 9

Which type of synaptic transmission (electrical or chemical) is multidirectional, and which is unidirectional?

Answer 9

Electrical synaptic transmission is multidirectional

Chemical synaptic transmission is unidirectional

Question 10

What is another name for a Metabotropic Receptor?

Answer 10

Muscarinic acetylcoline receptor

Question 11

What are the differences between spatial and temporal exitatory post synaptic potentials?

Answer 11

Spatial is where multiple neurons all fire at the same time, and their excitatory potentials add up to a post synaptic action potential - occurs all at once

Temporal is where one neuron fires over and over until it generates enough post synaptic membrane potential to reach threshold and fire an action potential

Question 12

What kind of neurotransmitter is glucagon?

Answer 12

Neuropeptide

Question 13

What kind of neurotransmitter is serotonin?

Answer 13

Biogenic Amine

Question 14

What type of protien is coupled with muscarinic acetylcoline receptors to bring about the intracellular affect?

What subgroup acts to carry the signal further?

Answer 14

G-Protien

The Beta and Gamma subunits

Question 15

Which of the two types of synaptic transmission has a synaptic gap?

Answer 15

Chemical synaptic transmission

Question 16

What are the two types of exitatory post synaptic potentials?

Answer 16

Spatial and Temporal

Question 17

What do neurons that use electrical junctions pass their signals through?

Answer 17

Gap Junctions

Question 18

What do Nicotinic Acetylcholine Receptors cause in the neurons that have them?

Answer 18

Increase in Na⁺ and a decrease K⁺ by increasing the permiability of the plasma membrane to these ions.

Question 19

What kind of neurotransmitter is GABA?

Answer 19

Amino Acid

Question 20

Which type of acetylcholine receptor is also called “Ionotropic?”

Answer 20

Nicotinic receptor

Question 21

What kind of acetylcholine receptors does the parasympathetic nervous system use?

Answer 21

Muscarinic Receptors

Question 22

What kind of neurotransmitters are endorphins?

Answer 22

Neuropeptides

Question 23

What neurotransmitter has nicotinic and muscarinic receptors?

Answer 23

Acetylcholine

Question 24

What kind of neurotransmitter is Epinephrine?

Answer 24

Biogenic Amine

Question 25

What are the four criteria for a molecule to be a neurotransmitter?

Answer 25

1. Must be synthesized in a presynaptic neuron
2. Must be released in response to a presynaptic action potential
3. Must attach to, and cause a response in, a postsynaptic receptor
4. Must be able to be inactivated

Question 26

Which type of signal trasmission happens more quickly, electrical or chemical?

Answer 26

Electrical

Question 27

Which of the two types of synaptic transmission do you see in the autonomic nervous system?

Answer 27

Chemical