Learn: Unit 2 Test Review: Synaptic Transmission & Neurotransmitters

Voltage-gated channels

Channels that open or close in response to changes in membrane potential, allowing ions to flow across the membrane.

Ion-gated channels

Channels that open or close in response to the binding of specific ions or molecules, regulating ion flow across the membrane.

Glutamate

An amino acid that serves as a major excitatory neurotransmitter in the brain.

Gamma-amino butyric acid (GABA)

An amino acid that acts as the main inhibitory neurotransmitter in the brain.

Catecholamines

A class of monoamines that include neurotransmitters such as norepinephrine and dopamine, involved in the body's response to stress.

Norepinephrine (noradrenalin)

A neurotransmitter involved in arousal and alertness, part of the body's fight-or-flight response.

Dopamine

A neurotransmitter that plays a key role in reward, motivation, and motor control.

Indoleamines

A class of monoamines that includes serotonin, which is involved in mood regulation and other functions.

Serotonin

A neurotransmitter that contributes to feelings of well-being and happiness, and regulates mood, appetite, and sleep.

Nitric oxide

A soluble gas that acts as a signaling molecule in the nervous system and is involved in various physiological processes.

Acetylcholine

A neurotransmitter that plays a crucial role in muscle activation and is involved in memory and learning.

Endogenous opioids

Peptides produced by the body that bind to opioid receptors and are involved in pain relief and pleasure.

Substance P

A neuropeptide that functions as a neurotransmitter and is involved in the transmission of pain signals.

Oxytocin

A hormone and neurotransmitter that plays a role in social bonding, sexual reproduction, and during and after childbirth.

Antidiuretic hormone (ADH)

A hormone that helps regulate water balance in the body by promoting water reabsorption in the kidneys.

Cholecystokinin (CCK)

A hormone that stimulates digestion and regulates appetite by promoting the release of digestive enzymes and bile.

Types of synapses

The main types of synapses are chemical synapses, which use neurotransmitters, and electrical synapses, which allow direct ionic current flow between neurons.

Glial Cells

What Cells support and protect neurons, maintain homeostasis, form myelin, and provide support and protection for neurons in the nervous system.

Resting membrane potential

The electrical potential difference across the neuronal membrane when the neuron is not actively transmitting signals, typically around -70 mV.

Action potential

A rapid change in membrane potential that occurs when a neuron sends a signal along its axon, characterized by depolarization followed by repolarization.

Passive forces in membrane potential

The two passive forces are the concentration gradient and the electrical gradient, which influence the movement of ions across the membrane.

Active force in membrane potential

The active force is the sodium-potassium pump, which uses ATP to move sodium out of the cell and potassium into the cell, maintaining the resting membrane potential.

What are the two main types of forces that drive ion movement across a neuron's membrane?

• Passive forces (concentration gradients and electrical gradients/diffusion)

• Active forces (ATP-powered ion transport mechanisms)

Sodium (Na+) and Chloride (Cl-)

• Which two ions are primarily regulated by passive forces to influence membrane potential?

Potassium K+

Which ion is primarily maintained against its concentration gradient by an active force?

How do passive forces act on Sodium (Na+)

• Chemical Force: Higher concentration outside flows inward.

• Electrical Force: Negatively charged interior attracts positive Na+ inward.

Ligand-gated channels

Membrane protein pores that open or close in response to the binding of a specific chemical messenger, such as a neurotransmitter, allowing ions to pass through.

Neuropeptides

Short chains of amino acids synthesized and released by neurons that act as slow-acting neuromodulators or signaling molecules.

Monoamines

A class of neurotransmitters containing a single amino group connected to an aromatic ring, which includes catecholamines (such as dopamine and norepinephrine) and indoleamines (such as serotonin).

Postsynaptic membrane

The specialized surface of a receiving neuron or target cell located across the synaptic cleft, containing receptor proteins that bind neurotransmitters to initiate electrical or chemical responses.

Presynaptic Membrane

specialized outer boundary of a sending neuron (nerve cell) where chemical signals, called neurotransmitters, are released into the gap between neurons to pass a signal along.

Presynaptic Terminal

(also called the axon terminal or synaptic knob) is the swollen end of a sending neuron's axon that holds neurotransmitters in tiny sacs and sends electrical or chemical signals to a target cell.

Synaptic Cleft

The tiny fluid-filled gap between the presynaptic neuron (the sender) and the postsynaptic neuron (the receiver) across which neurotransmitters diffuse.

Synaptic Vesicle

Tiny, membrane-bound sphere inside the presynaptic terminal that stores neurotransmitters and releases them when an electrical signal arrives.

Chemical Synapses

The entire junction where two nerve cells communicate using chemical messengers (neurotransmitters) instead of direct electrical contact.

Electrical Synapses

Direct physical bridge between two neurons that allows electric current and ions to flow straight from one cell into the next without using chemical messengers.

Axodendritic Synapse

Connects an axon terminal to a dendrite. This is the standard input pathway for integration.

Axosomatic Synapse

Connects an axon terminal directly to the receiving cell's soma (cell body). These typically exert strong control over whether the receiving cell fires.

Axoaxonic Synapse

Connects an axon terminal directly to another axon terminal. These act as "volume knobs" to fine-tune signal release before it reaches the target.

Dendrodendritic Synapse

A direct connection between dendrites of two neurons, allowing local processing without involving axons.