Neurotransmitter Release and Synaptic Transmission

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Questions and Answers

What is the function of the presynaptic terminal?

Receives neurotransmitters

Contains specialized receptors for neurotransmitters

Initiates the action potential

Converts electrical signal into a chemical signal (correct)

Which neurotransmitter is known to be the most abundant in the nervous system?

Glycine

Acetylcholine

Glutamate (correct)

GABA

What type of channels are controlled by a neurotransmitter?

Potassium channels

Mechanically-gated channels

Ligand-gated channels (correct)

Voltage-gated channels

In Sherrington's concept of the synapse, what does an input result in?

Excitation or inhibition Signup and view all the answers

What happens when a neurotransmitter binds to an ionotropic receptor?

The receptor opens a central channel for ions to pass through Signup and view all the answers

Which neurotransmitter opens chloride gates, letting negatively charged ions enter faster?

Glycine Signup and view all the answers

What type of chemicals are released by postsynaptic neurons to inhibit further release of transmitter?

Nitric Oxide, anandamide, and 2-AG Signup and view all the answers

What is the primary purpose of electrical synapses?

To allow for faster transmission of signals between neurons Signup and view all the answers

Which of the following is an example of an electrical synapse?

The cells that control your rhythmic breathing Signup and view all the answers

What is the purpose of the inhibitory chemicals released by postsynaptic neurons?

To suppress the release of transmitter from the presynaptic terminal Signup and view all the answers

How do electrical synapses differ from chemical synapses?

Electrical synapses allow for faster transmission of signals, while chemical synapses are slower Signup and view all the answers

What is the purpose of the illustration summarizing the effects of drugs on dopamine synapses?

To highlight the various ways in which drugs can affect the synthesis, release, action, reuptake, and breakdown of dopamine Signup and view all the answers

What is the primary function of inhibitory messages at synapses?

To prevent excessive excitation of the postsynaptic neuron Signup and view all the answers

Which statement accurately describes the concept of spontaneous firing rate?

It is the rate at which a neuron fires action potentials in the absence of any synaptic input Signup and view all the answers

In the example provided, if a neuron's spontaneous firing rate is 10 action potentials per second, what would be the effect of a stream of EPSPs?

The firing rate would increase to 15 or more action potentials per second Signup and view all the answers

Which statement accurately describes the process of chemical transmission at synapses?

It relies on the release of chemical neurotransmitters from the presynaptic neuron Signup and view all the answers

In the example provided, if cell X has a threshold of +2, how many excitatory inputs from cells A and B are required for cell X to respond?

Inputs from both cell A and cell B are required Signup and view all the answers

What was the significance of Loewi's experiment involving the stimulation of the vagus nerve in a frog?

It demonstrated the existence of chemical transmission at synapses Signup and view all the answers

Study Notes

Synaptic Transmission

Delay occurs in transmission through a synapse
Excitatory messages can be regulated by inhibitory neurons
EPSP (excitatory postsynaptic potential) is a burst of excitation in a neuron
Inhibitory messages can regulate the timing of activity

Neuron Stimulation

Axons from multiple cells can stimulate a single cell
Threshold of stimulation determines response
+1 unit stimulation can lead to response, while +2 units may be required for stimulation

Spontaneous Firing Rate

Neurons have a spontaneous firing rate without synaptic input
EPSPs increase firing rate, while IPSPs decrease it

Chemical Transmission

Most synapses rely on chemical processes
Chemical transmission involves release and reception of chemicals
Nitric oxide and anandamide are examples of chemicals involved in transmission

Electrical Synapses

Gap junctions allow direct contact between neuron membranes
Electrical transmission is faster than chemical transmission
Electrical synapses are used in cases requiring exact synchrony between cells

Hormones

Hormones are chemicals secreted by cells to influence other cells
Hormones are conveyed by the blood stream

Presynaptic and Postsynaptic Terminals

Presynaptic terminal is where electrical signal is converted to chemical signal
Postsynaptic terminal membrane contains specialized receptors
Calcium entry into the terminal leads to exocytosis

Activating Receptors

Ionotropic effects are brief on or off effects
Ionotropic synapse has localized effects on one point on the membrane
Transmitter-gated or ligand-gated channels are controlled by neurotransmitters

Neurotransmitters

Glutamate is the most abundant excitatory neurotransmitter in the nervous system
GABA is an inhibitory neurotransmitter that opens chloride gates
Glycine is an inhibitory neurotransmitter found mostly in the spinal cord

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Description

Learn about the process of neurotransmitter release at the presynaptic terminal and its effects on the postsynaptic cell. Understand the conversion from electrical to chemical signals and the role of specialized receptors in synaptic transmission.