Nervous System and Neuron Structure

A set of flashcards covering key vocabulary and concepts related to the nervous system and neuron structures based on lecture notes.

Ganglion

A knot-like swelling where neuron cell bodies are concentrated in the peripheral nervous system.

Visceral motor division

Carries impulses from the central nervous system that regulate the activity of smooth muscle, cardiac muscle, and glands.

Interneurons

Neurons that receive signals from many other neurons, process information, and make decisions for body responses.

Afferent neurons

Neurons that conduct signals from receptors to the central nervous system.

Excitability (Irritability)

The ability of neurons to respond to stimuli by producing electrical signals.

Axon hillocks

The trigger zones for nerve impulses in the neurons.

Nissl bodies

Sites of protein synthesis in the neuron.

Nodes of Ranvier

Locations where depolarization of the membrane occurs during saltatory conduction.

Oligodendrocytes

Cells that form the myelin sheaths in the central nervous system.

Schwann cells

Cells that form the myelin sheath in the peripheral nervous system.

Astrocytes

Cells that have extensions contacting blood capillaries, forming the blood-brain barrier.

Unipolar neurons

Neurons with a single process leading away from the soma, branching like a 'T'.

Multipolar neurons

The most common type of neurons found in the brain and spinal cord.

Bipolar neurons

Neurons that have one axon and one dendrite.

Axolemma

The membrane of the axon.

Axoplasm

The cytoplasm of the axon.

Neurilemma

The outermost coil of the myelin sheath.

Myelin sheath

An insulating layer that electrically insulates the axon.

Hyperpolarization

An increase in membrane potential where the interior of the cell becomes more negative.

Depolarization

A reduction in membrane potential where the interior of the cell becomes less negative.

Local potentials

Graded potentials that can be either excitatory or inhibitory.

Action potentials

Electrical signals that follow an all-or-none law and do not get weaker with distance.

Postsynaptic potential

A local potential produced in the synapse when sodium enters the cell.

Repolarization

A process that occurs when gated potassium channels open following depolarization.

Calcium

Triggers exocytosis of synaptic vesicles releasing acetylcholine across the synaptic cleft.

Meninges

The membranes covering the brain and spinal cord, consisting of pia mater, arachnoid mater, and dura mater.

Cauda equina

A bundle of spinal nerves in the lumbar/sacral region.

Perineurium

The connective tissue surrounding each fascicle of nerve fibers.

Epineurium

The dense irregular connective tissue surrounding each nerve.