Function of the Nervous System and Neuron Structure

This set of flashcards covers key vocabulary and definitions related to the function of the nervous system and the structure of neurons.

Nervous System Functions

Sensory functions, integrating functions, and motor functions.

Neuron

A nerve cell that responds to stimuli, conducts nerve impulses, and produces neurotransmitters.

Dendrites

Parts of a neuron that receive impulses or stimuli and carry them toward the cell body.

Cell Body (Soma)

Central part of the neuron that maintains the cell and contains the nucleus.

Axon

Conducts impulses away from the cell body to another neuron or effector cell.

Schwann Cell

Specialized glial cell that forms myelin in nerves outside the brain and spinal cord.

Myelin Sheath

Covers the axon and is produced by Schwann cells, increasing impulse conduction speed.

Node of Ranvier

Small gap in the myelin sheath between adjacent glial cells.

Telodendron

Branching end of the axon that transmits impulses to other cells.

Gray Matter

Contains most neuron cell bodies; initiates many nerve impulses.

White Matter

Consists mainly of myelinated nerve fibers; carries impulses in and out of gray matter.

Polarization

Condition where the inside of the neuron is more negative relative to the outside.

Sodium-Potassium Pump

Maintains the concentration gradient of Na⁺ outside and K⁺ inside the neuron.

Resting Membrane Potential

The electrical charge difference across the neuron's membrane when it is at rest, typically around -70 mV.

Depolarization

Occurs when sodium ions rush into the neuron, making the inside more positive.

Repolarization

Process of returning the neuron to its resting potential by allowing potassium ions to exit.

Action Potential

A rapid rise and fall in voltage across the neuron’s membrane; the nerve impulse.

Synapse

The junction where two neurons communicate.

Presynaptic Neuron

The neuron that sends the signal across the synapse.

Postsynaptic Neuron

The neuron that receives the signal on the other side of the synapse.

Neurotransmitters

Chemical messengers that transmit signals between neurons.

Excitatory Neurotransmitters

Increase the likelihood that a neuron will fire.

Inhibitory Neurotransmitters

Decrease the likelihood that a neuron will fire.

Cerebrum

Part of the brain responsible for conscious thought, sensory interpretation, and initiating voluntary muscle movements.

Cerebellum

Coordinates movement, balance, and posture.

Blood-Brain Barrier

Protects the brain by preventing harmful substances in the bloodstream from entering brain cells.

Autonomic Nervous System (ANS)

Controls involuntary body functions such as heart rate, digestion, and respiratory rate.

Sympathetic Nervous System (SNS)

Part of the ANS responsible for the 'fight-or-flight' response.

Parasympathetic Nervous System (PNS)

Part of the ANS responsible for 'rest-and-restore' functions.

Reflex Arc

Pathway through which reflexes occur, involving sensory neurons, interneurons, and motor neurons.

Somatic Reflexes

Reflexes involving skeletal muscles.

Autonomic Reflexes

Reflexes involving internal organs.

Neurological Testing

Used to determine reflex activity and identify damage in the nervous system.

Disuse Atrophy

Shrinking of muscles due to lack of use or neural stimulation.