Central and Peripheral Nervous Systems Overview

Flashcards covering essential vocabulary and concepts from the lecture on the central and peripheral nervous systems.

Central Nervous System (CNS)

Composed of the brain and spinal cord.

Peripheral Nervous System (PNS)

Includes all nervous tissue outside the CNS.

Neuron

A cell responsible for communication in the nervous system.

Glial Cell

A supporting cell that provides a framework for neurons.

Soma

The cell body of a neuron.

Dendrites

Extensions from the soma that receive stimuli.

Axon

A fiber that connects a neuron to its target.

Gray Matter

Bundles of axons that contain many cell bodies.

White Matter

Regions with many axons, characterized by myelination.

Nucleus (in CNS)

A localized collection of neuron cell bodies.

Ganglion

A localized collection of neuron cell bodies in the PNS.

Tract

A bundle of axons in the CNS.

Nerve

A bundle of axons in the PNS.

Optic Nerve

Axons leaving the retina to the brain, classified as PNS.

Optic Tract

Axons within the brain that originate from the retina, classified as CNS.

Sensation

The process of receiving information about the environment.

Stimulus

An event that registers a change from homeostasis.

Motor Function

The generation of responses to sensory information.

Somatic Nervous System (SNS)

Responsible for voluntary motor responses.

Autonomic Nervous System (ANS)

Controls involuntary functions for homeostasis.

Enteric Nervous System (ENS)

Controls smooth muscle and glandular tissue in the digestive system.

Electrical Signals

Signals that communicate information about sensations in neurons.

Synapse

Specialized area of contact for communication between neurons.

Unipolar Neuron

Has one process that splits into two branches for sensory input.

Bipolar Neuron

Has two processes, one axon and one dendrite, found in the retina.

Multipolar Neuron

Contains multiple dendrites and one axon.

Astrocyte

A star-shaped glial cell that supports neurons in the CNS.

Oligodendrocyte

Glial cell that insulates axons in the CNS.

Microglia

Small glial cells that ingest and digest damaged cells and pathogens.

Ependymal Cell

Glial cell that filters blood to produce cerebrospinal fluid.

Cerebrospinal Fluid (CSF)

Fluid that circulates through the CNS.

Choroid Plexus

Structure in ventricles that produces cerebrospinal fluid.

Satellite Cell

Glial cell in the PNS that surrounds neuron cell bodies.

Schwann Cell

Glial cell that insulates a single axon in the PNS.

Myelin

Fatty substance that insulates axons and facilitates signal transmission.

Myelin Sheath

Multiple layers of myelin surrounding an axon.

Node of Ranvier

Gaps between segments of myelin along an axon.

Phagocytosis

Process by which microglia ingest and digest cells.

Reflex

An involuntary response to stimuli.

Stimuli Types

Includes chemical, physical, light, and sound for sensory input.

Homeostasis

The maintenance of stable internal conditions.

Resting Potential

The electrical charge difference across a neuron's membrane when not transmitting signals.

Action Potential

Rapid change in membrane potential that propagates along an axon.

Neurotransmitter

Chemical messengers that transmit signals across synapses.

Depolarization

Loss of difference in charge across a neuron's membrane.

Hyperpolarization

Increase in charge difference across a neuron's membrane.

Threshold

The level of stimulation required to trigger an action potential.

Refractory Period

Period during which a neuron cannot fire another action potential.

Cortex

Outer layer of the brain involved in higher cognitive functions.