Neuroscience Chapter: Synapses

The junction between a neuron and another cell, allowing information transfer.

The cell before the synapse, sending information.

The cell after the synapse, receiving information.

A synapse between a neuron and a muscle cell.

Synapses that establish a direct connection between neurons, allowing ions to flow freely.

Synapses that utilize chemical messengers to transfer information across a gap.

The space between the presynaptic and postsynaptic cells in a chemical synapse.

Chemical messengers released by the presynaptic neuron, acting on receptors in the postsynaptic cell.

A neurotransmitter responsible for initiating muscle contractions and playing a role in learning and memory within the central nervous system (CNS). It is found in both the CNS and the peripheral nervous system (PNS).

Proteins that help fuse synaptic vesicles with the presynaptic membrane, releasing neurotransmitters into the synaptic cleft.

A SNARE protein located on the vesicle membrane.

A SNARE protein located on the target membrane.

A neurotoxin produced by bacteria that inhibits the release of acetylcholine from synaptic vesicles, causing paralysis.

A condition caused by botulinum toxin, characterized by muscle weakness and paralysis.

The arrival of the action potential (AP) at the presynaptic terminal triggers a series of events leading to the release of neurotransmitters.

Voltage-gated calcium channels open, allowing calcium ions (Ca2+) to rush into the presynaptic terminal.

Vesicles containing neurotransmitters fuse with the presynaptic membrane, releasing their contents into the synaptic cleft.

Neurotransmitters bind to specific receptors on the postsynaptic membrane, triggering a response in the postsynaptic neuron.

A graded potential that occurs in the postsynaptic membrane after neurotransmitter binding.

A type of postsynaptic potential that increases the likelihood of a postsynaptic action potential occurring.

A type of postsynaptic potential that decreases the likelihood of a postsynaptic action potential occurring.

The most common excitatory neurotransmitter in the CNS, involved in functions such as learning and memory.

A type of poison that acts at the neuromuscular junction, preventing muscle contraction by blocking acetylcholine receptors.

Transient electrical changes in the postsynaptic neuron caused by chemical signals transmitted from the presynaptic neuron. These changes can be either excitatory (EPSP) or inhibitory (IPSP).

A type of postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential.

A type of postsynaptic potential that makes the postsynaptic neuron less likely to fire an action potential.

When many presynaptic neurons send signals to a single postsynaptic neuron.

When a single presynaptic neuron sends signals to multiple postsynaptic neurons.

The sum of all EPSPs and IPSPs at the postsynaptic neuron.

The ability of repeated stimulation to strengthen the connection between neurons.

Botulinum toxin inhibits the release of acetylcholine, a neurotransmitter crucial for muscle contraction. It does this by targeting and disrupting the proteins involved in vesicle fusion, effectively preventing the release of acetylcholine from the presynaptic neuron.

Botulinum toxin, produced by the bacterium Clostridium botulinum, can be found in soil, water, and some food products. It thrives in oxygen-free environments and produces toxins. This toxin can lead to botulism, a serious illness caused by the paralysis of muscles.

Botulism is a potential risk associated with consuming homemade canned foods, particularly low-acid foods such as meat and vegetables. The improper sterilization of these foods can allow for the growth of Clostridium botulinum and the production of its toxin.

Honey is a natural source of botulinum spores. Infants, with their developing immune systems, are highly susceptible to botulism. Therefore, honey should be avoided for infants to prevent the risk of developing botulism.

Tetanus toxin, produced by Clostridium tetani, disrupts neurotransmission by specifically targeting and destroying synaptobrevin, a critical protein involved in the release of inhibitory neurotransmitters. This disruption leads to an overactivity of motor neurons causing spastic paralysis.

Lambert-Eaton syndrome is an autoimmune disorder that targets and destroys specific calcium channels in the nerves responsible for skeletal muscle innervation. This destruction reduces the release of acetylcholine, leading to muscle weakness.

Myasthenia gravis, an autoimmune disease, involves the production of antibodies that attack acetylcholine receptors (AChR) at the neuromuscular junction. This attack disrupts the normal neurotransmission process, leading to muscle weakness and fatigue.

Curare is a natural compound derived from tropical plants known for its muscle relaxant properties. It blocks the action of acetylcholine at the neuromuscular junction, preventing muscle contraction. This action has historically been used as a paralyzing agent and is currently used in certain medical contexts.