The Nervous System

These flashcards cover key terms and definitions related to the structure and function of the nervous system, including neurons, neurotransmitters, and synapses.

Central Nervous System (CNS)

The part of the nervous system that includes the brain and spinal cord.

Peripheral Nervous System (PNS)

The part of the nervous system that includes cranial and spinal nerves outside of the CNS.

Neuron

The basic structural and functional unit of the nervous system that conducts electrochemical impulses.

Neuroglia

Supporting cells in the nervous system that assist neurons and can divide but do not conduct impulses.

Interneuron

A multipolar neuron located entirely within the CNS that integrates functions of the nervous system.

Sensory neuron (afferent neuron)

A neuron that transmits impulses from sensory receptors into the CNS.

Motor neuron (efferent neuron)

A neuron that transmits impulses from the CNS to effector organs, such as muscles.

Myelin sheath

An insulating layer around axons formed by Schwann cells in the PNS or oligodendrocytes in the CNS.

Action potential

A rapid change in membrane potential that propagates along the axon of a neuron.

Depolarization

The process by which the membrane potential becomes more positive due to the influx of Na+ ions.

Repolarization

The process by which the membrane potential returns to its resting state after depolarization.

Hyperpolarization

The process by which the membrane potential becomes more negative than the resting potential.

Blood-Brain Barrier (BBB)

A selective barrier that prevents certain substances from entering the brain from the bloodstream.

Synapse

The functional connection between a neuron and the cell it signals, which may be another neuron or a muscle cell.

Neurotransmitter

Chemical messengers that transmit signals across the synapse from the presynaptic neuron to the postsynaptic cell.

Acetylcholine (ACh)

A neurotransmitter that can have excitatory or inhibitory effects depending on the receptor it binds to.

EPSP (Excitatory Postsynaptic Potential)

A graded depolarization of the postsynaptic membrane that moves it closer to threshold.

IPSP (Inhibitory Postsynaptic Potential)

A graded hyperpolarization of the postsynaptic membrane that moves it further from threshold.

Refractory period

The time during which a neuron is unable to generate another action potential after an initial action potential.

Long-term potentiation (LTP)

A long-lasting enhancement in signal transmission between two neurons that results from recent patterns of activity.

Long-term depression (LTD)

A long-lasting decrease in synaptic strength that occurs when a synapse is activated by a low frequency of stimulation.

Demyelinating diseases

Conditions that involve the loss of myelin sheath around nerves, affecting signal transmission.

G-protein-coupled receptors

Receptors that initiate a signaling cascade using G-proteins when a ligand binds.

Monoamines

A group of neurotransmitters derived from amino acids, including dopamine, norepinephrine, and serotonin.

Neuropeptides

Short chains of amino acids that act as neurotransmitters and play a role in modulating pain and reward.

Endocannabinoids

Lipid-based retrograde neurotransmitters that bind to cannabinoid receptors and are involved in many physiological processes.