Chapter 5.1 Flashcards
Neurotransmitter
Chemicals that transmit signals across a synapse from one neuron to another target neuron, muscle cell, or gland cell. They play critical roles in communication within the nervous system.
Example: Acetylcholine, dopamine, glutamate
Nitric Oxide (NO)
A gaseous neurotransmitter involved in various physiological processes, including vasodilation and neurotransmission. It diffuses freely across membranes to influence nearby cells.
Example: NO is important in regulating blood flow
Noradrenergic Neuron
A neuron that primarily uses norepinephrine (noradrenaline) as its neurotransmitter. These neurons are involved in regulating arousal, attention, and stress responses.
Example: Noradrenergic neurons play a role in the fight-or-flight response
Norepinephrine (NE)
Also known as noradrenaline, it acts as both a hormone and neurotransmitter. It is crucial for the fight-or-flight response, increasing heart rate and blood flow to muscles.
Example: NE is released in response to stress
Obsessive-Compulsive Disorder (OCD)
A mental disorder characterized by unwanted repetitive thoughts (obsessions) and behaviors (compulsions) that the individual feels driven to perform. It often leads to significant distress and impairment.
Example: OCD can interfere with daily activities
Parkinson Disease
A neurodegenerative disorder that affects movement control, characterized by tremors, rigidity, and bradykinesia (slowness of movement). It results from the loss of dopamine-producing neurons in the substantia nigra.
Example: Parkinson’s disease is treated with dopaminergic medications
Peptide Hormone
Hormones made of amino acids that regulate various physiological functions. Examples include insulin, which controls blood glucose levels, and oxytocin, which influences social bonding and reproductive behaviors.
Example: Insulin is a peptide hormone
Postsynaptic Membrane
The membrane on the receiving side of a synapse, which contains receptors for neurotransmitters. This membrane undergoes changes in electrical potential in response to neurotransmitter binding.
Example: Postsynaptic membrane activation leads to signal transmission
Presynaptic Membrane
The membrane on the transmitting side of a synapse, where neurotransmitters are released. It contains the machinery necessary for neurotransmitter exocytosis.
Example: Presynaptic membrane contains synaptic vesicles
Quantum (pl. Quanta)
The minimum amount of neurotransmitter released from a presynaptic vesicle into the synaptic cleft. Each quantum produces a small postsynaptic potential.
Example: Quanta release is stochastic
Rate-Limiting Factor
The slowest step in a metabolic pathway that determines the overall rate of the process. In neurotransmitter synthesis, it often involves an enzyme that regulates the production of the neurotransmitter.
Example: Tyrosine hydroxylase is a rate-limiting enzyme in dopamine synthesis
Reuptake
The process by which neurotransmitters are reabsorbed by the presynaptic neuron after being released into the synaptic cleft. This mechanism helps terminate the neurotransmitter’s action and recycle it for future use.
Example: Selective serotonin reuptake inhibitors (SSRIs) block serotonin reuptake
Schizophrenia
A severe mental disorder characterized by distorted thinking, perception, emotions, language, sense of self, and behavior. Symptoms often include hallucinations, delusions, and disorganized thinking.
Example: Schizophrenia has genetic and environmental risk factors
Second Messenger
Intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules. They amplify the signal and trigger various cellular responses.
Example: cAMP is a second messenger in the cAMP signaling pathway
Serotonin (5-HT)
A neurotransmitter that regulates mood, appetite, sleep, memory, and learning. Imbalances in serotonin levels are associated with mood disorders such as depression and anxiety.
Example: Selective serotonin reuptake inhibitors (SSRIs) target serotonin reuptake
Small-Molecule Transmitter
Neurotransmitters that are small and typically synthesized from dietary nutrients. Examples include acetylcholine, dopamine, and glutamate.
Example: Acetylcholine is a small-molecule transmitter
Steroid Hormone
Hormones derived from cholesterol that pass through cell membranes and bind to intracellular receptors to influence gene expression. Examples include cortisol and estrogen.
Example: Cortisol is a steroid hormone
Storage Granule
Vesicles in the presynaptic neuron that store neurotransmitters until they are released into the synaptic cleft. They ensure a ready supply of neurotransmitter for synaptic transmission.
Example: Synaptic vesicles are storage granules
Subunit
A single protein molecule that assembles with other protein molecules to form a functional complex, such as an ion channel or receptor. These complexes can be multimeric, meaning they consist of multiple subunits.
Example: Glutamate receptor subunits form ion channels
Synaptic Cleft
The small gap between the presynaptic and postsynaptic membranes. Neurotransmitters cross this gap to transmit signals between neurons.
Example: Synaptic cleft distance affects signal transmission
Synaptic Vesicle
Membrane-bound sacs in the presynaptic neuron that contain neurotransmitters. They release their contents into the synaptic cleft through exocytosis.
Example: Synaptic vesicles store neurotransmitters
Transmitter-Activated Receptor
A receptor on the postsynaptic membrane that binds to neurotransmitters, initiating a cellular response. These receptors can be ionotropic or metabotropic.
Example: Glutamate receptors are transmitter-activated receptors
Transporter
Proteins that move neurotransmitters across cell membranes, often involved in reuptake into the presynaptic neuron or uptake into glial cells. They help regulate neurotransmitter levels in the synaptic cleft.
Example: Serotonin transporter regulates serotonin levels
Tripartite Synapse
A synapse involving the presynaptic neuron, the postsynaptic neuron, and surrounding glial cells, particularly astrocytes. This model highlights the active role of glial cells in synaptic transmission and modulation.
Example: Astrocytes modulate synaptic transmission in tripartite synapses
Zinc
A trace element that acts as a cofactor for many enzymes and is involved in numerous biological processes. In the brain, zinc can modulate neurotransmitter activity and influence synaptic plasticity.
Example: Zinc deficiency impairs neurotransmission
