Neuroscience Chapter: Synapses

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What distinguishes an electrical synapse from a chemical synapse?

It allows ions to flow freely between cells. (correct)

It relies on neurotransmitters for signal transmission.

It creates a synaptic cleft for communication.

It requires a physical gap for transmission.

Which type of synapse is formed between a neuron and a muscle cell?

Electrical synapse

Axoaxonic synapse

Axodendritic synapse

Neuromuscular junction (correct)

What is the primary feature of chemical synapses?

Direct connection between neuron membranes.

The existence of a synaptic cleft. (correct)

Stimulus transmission without chemical agents.

Presence of gap junctions.

What role do gap junctions play in electrical synapses?

They allow rapid transmission of electrical signals. Signup and view all the answers

Which of the following most accurately describes the postsynaptic structure in a chemical synapse?

Motor end plate. Signup and view all the answers

What type of synapse is characterized by synaptic transmission that can inhibit or excite postsynaptic neurons?

Chemical synapses Signup and view all the answers

What causes the release of neurotransmitters in a chemical synapse?

Calcium ions entering the presynaptic neuron. Signup and view all the answers

How far apart are the cells connected by gap junctions in electrical synapses?

2-4 nanometers Signup and view all the answers

What is the mechanism of action of Botulinum toxin?

It destroys SNARE proteins, preventing neurotransmitter release. Signup and view all the answers

Which conditions is Botulinum toxin NOT used to treat?

Osteoporosis Signup and view all the answers

How can one become infected with botulinum toxin?

Ingesting improperly canned foods Signup and view all the answers

What is the primary effect of Tetanus toxin?

It blocks the release of inhibitory neurotransmitters. Signup and view all the answers

What autoimmune effect is observed in Lambert-Eaton Syndrome?

Destruction of specific voltage-gated Ca2+ channels. Signup and view all the answers

What results from autoantibodies formed in Myasthenia Gravis?

Accumulation of acetylcholine in the synaptic cleft. Signup and view all the answers

What is the primary function of acetylcholine in the central nervous system?

Initiating muscle contractions Signup and view all the answers

Which of the following statements accurately describes electrical synapses?

They have a narrow synaptic gap and no synaptic delay. Signup and view all the answers

What is a common source of botulinum spores that poses a risk to infants?

Honey Signup and view all the answers

What are V-SNARE proteins primarily responsible for?

Merging synaptic vesicles with the target membrane. Signup and view all the answers

What type of paralysis is associated with Tetanus toxin action?

Spastic paralysis Signup and view all the answers

What type of synaptic delay is characteristic of chemical synapses?

A significant delay before signal transmission. Signup and view all the answers

Which disease is linked to dysfunction at the neuromuscular junction due to antibody interference?

Myasthenia Gravis Signup and view all the answers

What role does synaptotagmin play in the SNARE complex?

It enhances the assembly upon calcium binding. Signup and view all the answers

Which characteristic differentiates chemical synapses from electrical synapses?

Chemical synapses utilize neurotransmitters for transmission. Signup and view all the answers

How does botulinum toxin affect the nervous system?

It blocks the release of neurotransmitters. Signup and view all the answers

What is the primary action of curare at the neuromuscular junction?

Blocks acetylcholine receptors Signup and view all the answers

Which neurotransmitter is primarily responsible for producing excitatory post-synaptic potentials (EPSPs)?

Glutamate Signup and view all the answers

How does an inhibitory post-synaptic potential (IPSP) affect the postsynaptic neuron?

It hyperpolarizes the neuron. Signup and view all the answers

What does the term convergence refer to in neural signaling?

Signals from multiple presynaptic neurons to one postsynaptic neuron. Signup and view all the answers

What outcome occurs when the summation of EPSPs is higher than that of IPSPs?

The postsynaptic neuron is stimulated. Signup and view all the answers

Which of the following ions is involved in the hyperpolarization of the postsynaptic neuron during an IPSP?

Potassium (K) Signup and view all the answers

What occurs when acetylcholine (Ach) accumulates in the synaptic cleft due to competitive blockade?

Inhibition of respiratory muscles. Signup and view all the answers

What triggers the opening of voltage-gated Ca+2 channels in the presynaptic neuron?

Depolarization of the presynaptic neuron Signup and view all the answers

Which type of potential results from the opening of sodium (Na) channels in the postsynaptic neuron?

EPSP Signup and view all the answers

What happens after the fusion of the vesicle with the presynaptic membrane?

Neurotransmitters are released into the synaptic cleft Signup and view all the answers

What type of receptor is the nicotinic Ach receptor (nAcHR)?

Ligand-gated ion channel Signup and view all the answers

What determines the number of vesicles released into the synaptic cleft?

Intracellular Ca+2 concentration in the presynaptic terminal Signup and view all the answers

What effect does the binding of Ach to nAcHR receptors have on the ion flow?

Na+ enters the cell while K+ exits Signup and view all the answers

What is the result of the accumulation of excitatory postsynaptic potentials (EPP)?

Opening of further voltage-gated Na+ channels Signup and view all the answers

Which neurotransmitter is the most common excitatory neurotransmitter in the CNS?