Neural Anatomy and Physiology

Resting membrane potential

The electrical potential difference across a cell membrane when the cell is at rest.

Excitable

Neurons are highly responsive to stimuli and can rapidly change their membrane potential.

Electrochemical gradient

The combined electrical and chemical gradients that influence the movement of ions across a membrane.

Action potential

A rapid and temporary change in membrane potential that travels along the axon of a neuron.

Graded potentials

Short-lived changes in membrane potential that can vary in size, unlike action potentials which are all-or-nothing.

Synapse

The junction between two neurons or between a neuron and an effector where information transfer occurs.

Postsynaptic neuron

The neuron that receives the signal across the synapse.

Presynaptic neuron

The neuron that transmits the signal to the postsynaptic neuron.

Neurotransmitter

Chemical messengers released from presynaptic neurons that bind to receptors on postsynaptic neurons.

Temporal summation

The process by which multiple signals from a single presynaptic neuron are summed over time.

Spatial summation

The process by which simultaneous signals from multiple presynaptic neurons are summed.

Hyperpolarization

An increase in membrane potential making the inside of the cell more negative than the resting potential.

Depolarization

A decrease in membrane potential making the inside of the cell less negative than the resting potential.

Sodium-potassium pump

A protein pump that moves 3 sodium ions out and 2 potassium ions in to maintain resting membrane potential.

Chemical synapse

A synapse where neurotransmitters are released from the presynaptic terminal and bind to the postsynaptic receptor.

Electrical synapse

A synapse where neurons are directly connected by gap junctions, allowing rapid communication.

Myelination

The process of forming a myelin sheath around nerve fibers, which increases signal conduction speed.

Neuromodulator

A chemical messenger released by neurons that affects the strength of synaptic transmission without directly causing EPSPs or IPSPs.

Long-term potentiation

A persistent strengthening of synapses based on recent patterns of activity, associated with learning and memory.

Refractory period

The period following an action potential during which a neuron is unable to fire another action potential.

Diverging circuit

A neural circuit in which one neuron spreads its output to multiple other neurons.

Converging circuit

A neural circuit in which multiple neurons synapse onto a single neuron.

Neural tube

The embryonic precursor to the central nervous system, which develops from the ectoderm.

Astrocytes

Star-shaped glial cells in the brain and spinal cord that support neurons and aid in synapse formation.

Axoaxonal synapse

A synaptic connection between the axon of one neuron and the axon of another.

Substance P

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

G protein-linked receptors

Receptors that act through a second messenger system to initiate cellular responses.

Channel-linked receptors

Ligand-gated ion channels that open in response to neurotransmitter binding, causing immediate changes in ion flow.

Resistance

A hindrance to the flow of electrical charge, impacting how current flows in the nervous system.

Insulator

A substance with high electrical resistance, preventing the flow of electric current.