Neuroanatomy Overview

The ability of the lipid bilayer in a neuronal membrane to store electrical charge on either side. This property influences how signals propagate through the membrane.

The passive transmission of electrical signals, such as postsynaptic potentials, along dendrites towards the cell body without active amplification.

The gradual decrease in the amplitude of an electrical signal as it travels along a dendrite.

The distance an electrical signal can travel along a dendrite before it decays to 37% of its original strength.

The time it takes for an electrical signal to decay to 63% of its original strength at a specific point on a dendrite.

Specialized proteins embedded in the cell membrane that allow the passage of specific ions across the membrane.

Ion channels that are always open, allowing a constant flow of ions across the membrane. They contribute to maintaining resting membrane potential.

Ion channels that open and close in response to specific stimuli, such as neurotransmitters, voltage changes, or mechanical force.

Neurons are the fundamental units of the nervous system, responsible for transmitting information throughout the body via electrical and chemical signals.

The cell body of a neuron, containing the nucleus and other essential organelles.

Branched extensions of a neuron that receive signals from other neurons.

A long, slender extension of a neuron that transmits signals to other neurons, muscles, or glands.

A fatty sheath that insulates the axon, speeding up the transmission of electrical signals.

Gaps in the myelin sheath where the axon is exposed, allowing for the recharging of the electrical signal during transmission.

A type of glial cell that produces myelin in the central nervous system.

The types of glial cells that maintain the chemical and ionic environment for neuronal signaling and participate in synapse formation.

A type of ionotropic glutamate receptor that is permeable to both sodium and calcium ions, but only allows their passage when depolarized, due to the presence of a magnesium block.

An inhibitory neurotransmitter that binds to GABA-A receptors, causing chloride ions to flow into the neuron, hyperpolarizing it and making it less likely to fire.

A type of ionotropic receptor that binds GABA and allows chloride ions to flow into the neuron, leading to hyperpolarization.

A type of ligand-gated chloride channel that is activated by glycine. It plays a role in inhibition in the spinal cord and brainstem.

A type of ion channel that is permeable to a specific type of ion. The selectivity is determined by the structure of the channel.

A protein complex that consists of three subunits and is involved in signal transduction pathways. They are activated by various receptors and can activate a variety of effectors, leading to diverse cellular responses.

A type of synapse where the presynaptic and postsynaptic neurons are directly connected through gap junctions, allowing ions to flow freely between them.

Specialized channels formed by proteins called connexins that connect the presynaptic and postsynaptic neurons in an electrical synapse, allowing for the direct flow of ions.

The strengthening of the connection between two neurons, making them more likely to fire together in the future. This process involves the insertion of more AMPA receptors and structural changes in the synapse.

The simultaneous activation of multiple synapses on a postsynaptic neuron can trigger LTP, even if one of the synapses is weakly stimulated. This means that the strong input can help strengthen the weaker input.

LTP specifically affects the synapse that receives high-frequency stimulation, leaving other synapses untouched.

At baseline, glutamate binds to both AMPA and NMDA receptors, but only AMPA receptors are active. NMDA receptors are blocked by magnesium ions (Mg²⁺).

When the neuron is sufficiently depolarized, for example by the activation of AMPA receptors, the magnesium block on NMDA receptors is removed.

The influx of calcium (Ca²⁺) through NMDA receptors activates signaling pathways inside the postsynaptic neuron, leading to the insertion of more AMPA receptors and structural changes in the synapse.

After LTP, the same amount of glutamate release from the presynaptic neuron causes a bigger postsynaptic response, indicating a stronger synapse.

LTP plays a crucial role in learning and memory by strengthening synaptic connections, enabling the brain to store information effectively.

A neurotoxin produced by bacteria, Botulinum toxin (BoTx) prevents the release of acetylcholine (ACh) at motor neurons.

Tetanus toxin (TeTx) blocks the release of inhibitory neurotransmitters, GABA and glycine, in the central nervous system (CNS).

Myasthenia gravis is an autoimmune disorder where antibodies attack and block acetylcholine receptors (AChRs) at the neuromuscular junction, leading to muscle weakness.

Nerve gases inhibit the breakdown of acetylcholine (ACh) by acetylcholinesterase, leading to prolonged stimulation of muscles and glands.

A glass microelectrode is inserted into the axon to measure the voltage difference between the inside and outside of the cell.

Voltage clamp is a technique to control the membrane potential and measure ionic currents flowing across the membrane.

The difference in electrical charge between the inside and outside of a neuron.

A technique for studying the electrical activity of neurons by measuring the changes in voltage across the membrane.

A patch clamp configuration where the pipette is gently attached to the cell membrane without disrupting it. This allows for the study of ion channel activity in their natural environment, often in living cells.

A patch clamp configuration where the pipette forms a seal on the membrane and gentle suction breaks through, allowing access to the cell's interior. This is used to study the cell's overall properties like membrane potential and ion channel function.

A patch clamp configuration where the cytoplasmic side of the membrane is exposed to the solution in the bath, allowing for the study of ion channel regulation by intracellular factors.

A patch clamp configuration where the extracellular side of the membrane is exposed to the bath. This allows for the study of the effects of extracellular ligands on ion channel function.

A variation of the patch clamp technique that allows for the measurement of ionic currents while preserving the integrity of the cell membrane.

The resulting I-V curves from patch clamping are used to analyze the flow of ions through channels, their conductance, gating mechanisms, and responses to various factors.

The patch clamp technique is a powerful tool for studying ion channels, allowing researchers to measure the flow of ions through individual channels in a controlled environment.