Nervous System: Nervous Tissue Practice Flashcards

Comprehensive vocabulary flashcards covering the anatomy and physiology of the nervous system, including neuron structure, glial cells, and nerve organization.

Sensory function

The process where receptors detect stimuli and send sensory signals to the spinal cord and brain.

Integrative function

The process where the brain and spinal cord determine the response to sensory input.

Motor function

The process where the brain and spinal cord send motor output via nerves to effectors such as muscles or glands.

Central nervous system (CNS)

The structural organization of the nervous system consisting of the brain and spinal cord.

Peripheral nervous system (PNS)

The structural organization of the nervous system consisting of nerves and ganglia.

Somatic sensory system

The part of the sensory nervous system that detects stimuli we consciously perceive.

Visceral sensory system

The part of the sensory nervous system that detects stimuli we typically do not perceive, such as signals from the heart or kidneys.

Somatic motor component

The part of the motor nervous system that sends voluntary signals to skeletal muscles.

Autonomic motor (visceral motor) component

The part of the motor nervous system that sends involuntary commands to the heart, smooth muscle, and glands.

Nerve

A bundle of parallel axons in the Peripheral nervous system.

Epineurium

A wrapping of dense irregular connective tissue that encloses the entire nerve.

Perineurium

Dense irregular connective tissue that wraps each fascicle, which is a bundle of axons in a nerve.

Endoneurium

Areolar connective tissue that wraps each individual axon to separate and electrically insulate them.

Ganglion

A cluster of neuron cell bodies in the Peripheral nervous system.

Mixed nerves

The most common type of nerves, containing both sensory and motor neurons.

Excitability

The ability of a neuron to respond to a stimulus, causing a change in the cell's membrane potential.

Conductivity

The ability of a neuron to propagate an electrical signal along its membrane.

Secretion

The release of a neurotransmitter from vesicles in response to conductive activity to influence a target cell.

Chromatophilic substance (Nissl bodies)

Material within the neuron cell body made of free and bound ribosomes.

Dendrites

Short, unmyelinated processes branching off the cell body that receive input and transfer it to the cell body.

Axon

A long process emanating from the axon hillock that carries signals; its cytoplasm is axoplasm and its membrane is axolemma.

Synaptic knobs

Tips at the distal end of axons that house synaptic vesicles containing neurotransmitters.

Neurofibrils

Bundles formed by the aggregation of neurofilaments (intermediate filaments) that provide tensile strength to the neuron.

Anterograde transport

Movement of material from the cell body toward the synaptic knobs.

Retrograde transport

Movement of used materials from the axon back to the cell body for breakdown and recycling.

Fast axonal transport

Movement along microtubules powered by motor proteins splitting ATP, occurring at about $400\,mm$ per day.

Slow axonal transport

Movement resulting from the flow of axoplasm, occurring at about $0.1$ to $3\,mm$ per day, moving only in an anterograde direction.

Multipolar neurons

The most common structural type of neuron, possessing many dendrites and one axon.

Interneurons (association neurons)

Neurons located within the CNS that receive, process, and integrate information; they make up $99\%$ of all neurons.

Electrical synapse

A fast connection where presynaptic and postsynaptic neurons are bound together by gap junctions, resulting in no synaptic delay.

Chemical synapse

A junction where a neurotransmitter is released into a fluid-filled gap called the synaptic cleft to bind to postsynaptic receptors.

Astrocytes

The most abundant glial cells in the CNS; they help form the blood-brain barrier and regulate tissue fluid composition.

Ependymal cells

Glial cells that line the cavities of the brain and spinal cord and assist in the production of cerebrospinal fluid.

Microglia

Small, phagocytic immune cells in the CNS that remove waste and unnecessary synapses.

Oligodendrocytes

Large CNS glial cells with extensions that wrap around multiple axons to form myelin sheaths.

Satellite cells

Glial cells in the PNS arranged around neuronal cell bodies in a ganglion to insulate and regulate nutrient exchange.

Neurolemmocytes (Schwann cells)

Flat cells that ensheath PNS axons with myelin to allow for faster action potential propagation.

Neurilemma

The periphery of a neurolemmocyte containing the cytoplasm and nucleus, formed during the myelination of PNS axons.

Neurofibril nodes (nodes of Ranvier)

Gaps between regions of myelin or between adjacent neurolemmocytes along an axon.

Multiple sclerosis

An autoimmune disorder characterized by progressive demyelination of neurons in the CNS and the formation of sclerosis (scarring).

Guillain-Barré syndrome

A condition involving the loss of myelin from peripheral nerves due to inflammation, typically resulting in muscle weakness.