Neurons and Synapses

These flashcards cover essential terms and concepts related to neurons and synapses, helping students prepare for exams in neuroscience.

Neuron

A nerve cell that uses electricity and chemicals to communicate.

Axon

Long projection of a neuron that transmits signals away from the cell body.

Dendrites

Branch-like structures that receive signals from other neurons.

Synapse

The small gap between two neurons where neurotransmitters are transmitted.

Central Nervous System (CNS)

Part of the nervous system consisting of the brain and spinal cord.

Peripheral Nervous System (PNS)

Connects the CNS to the rest of the body and includes sensory and motor neurons.

Sensory Neurons

Neurons that collect information from sensory organs and send it to the CNS.

Interneurons

Neurons that transmit signals between other neurons, typically within the CNS.

Motor Neurons

Neurons that activate muscle cells and bring about movement.

Neurotransmitter

Chemical substances that transmit signals across a synapse.

Glia

Supporting cells in the nervous system that provide structural and nutritional support for neurons.

Membrane Potential

The electrical potential difference across a neuron's membrane.

Resting Potential

The state of a neuron's membrane when it is at rest, typically -70mV.

Action Potential

A rapid increase in membrane potential that occurs when a neuron sends a signal.

Sodium-Potassium Pump

A protein that pumps sodium out of and potassium into the neuron, against their concentration gradients.

Hyperpolarization

An increase in the negativity of the membrane potential.

Depolarization

A decrease in the negativity of membrane potential, often caused by Na+ ions entering the cell.

Threshold

The level of depolarization needed to trigger an action potential.

Refractory Period

The period during which a neuron cannot initiate another action potential.

Myelin Sheath

A protective covering that surrounds axons, facilitating faster transmission of signals.

Nodes of Ranvier

Gaps in the myelin sheath that allow for rapid signal conduction.

Saltatory Conduction

The process of action potentials jumping from one node of Ranvier to another.

Excitatory Postsynaptic Potential (EPSP)

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

Inhibitory Postsynaptic Potential (IPSP)

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

Temporal Summation

The process where multiple EPSPs occurring over time add together to reach threshold.

Spatial Summation

The process where multiple EPSPs from different synapses add together to reach threshold.

Neurotransmitter Types

Five major classes: acetylcholine, biogenic amines, amino acids, neuropeptides, and gases.

Acetylcholine

A common neurotransmitter involved in muscle activation and many CNS functions.

Biogenic Amines

A group of neurotransmitters including epinephrine, norepinephrine, dopamine, and serotonin.

Amino Acids

Neurotransmitters like glutamate and GABA that are involved in excitatory and inhibitory signaling.

Neuropeptides

Short chains of amino acids that act as neurotransmitters, such as endorphins.

Endorphins

Neuropeptides that act as natural painkillers.

Nitric Oxide (NO)

A gas neurotransmitter involved in signaling pathways.

Carbon Monoxide (CO)

A gas transmitter in neuronal signaling.

Ligand-Gated Ion Channels

Channels that open in response to neurotransmitter binding, causing depolarization.

Chemical Synapse

A synapse where neurotransmitters are released to carry signals across the gap.

Electrical Synapse

A synapse where the signal passes directly through gap junctions between neurons.

Action Potential Stages

The steps involved in generating an action potential: resting, depolarization, threshold, repolarization.

Voltage Gradient

The difference in electrical charge across a neuron's membrane.

K+ (Potassium) Channels

Ion channels that allow potassium ions to flow out of the neuron during repolarization.

Na+ (Sodium) Channels

Ion channels that allow sodium ions to flow into the neuron during depolarization.

Nervous System Functions

Includes sensory input, integration of information, and motor output.

Ganglia

Clusters of nerve cell bodies in the PNS.

Schwann Cells

Glial cells in the PNS that form the myelin sheath around axons.

Oligodendrocytes

Glial cells in the CNS that produce myelin.

Neurotransmitter Receptors

Proteins on the postsynaptic cell that bind with neurotransmitters to induce a response.

EPSP and IPSP Interaction

EPSPs and IPSPs can counterbalance each other in neuron signaling.

Neural Communication

The transmission of signals between neurons through electrical and chemical means.

Neural Signaling

Process of transmitting information through neuronal action potentials.

Cell Body

The part of a neuron that contains the nucleus and organelles.

Presynaptic Cell

The neuron that releases neurotransmitters into the synapse.

Postsynaptic Cell

The neuron, muscle, or gland that receives neurotransmitters.

Neural Pathways

Series of interconnected neurons that form a communication route.

Signal Integration

The process of combining signals from multiple neurons.

Motor Output

Signals from the CNS that result in muscle movement.

Sensory Input

Signals from sensory organs that inform the CNS about the environment.

Chemical Communication

Transmission of signals through neurotransmitters across synapses.

Neuronal Structure

The physical arrangement and components of a neuron.

Signal Propagation

The process of action potentials traveling along an axon.

Calcium Ions (Ca2+)

Ions that play a key role in neurotransmitter release at synapses.