Nervous Tissue Lecture Review

A set of 45 question-and-answer flashcards covering key terms, structures, and functions of nervous tissue and neurons.

What is the process called when the nervous system decides whether or not an output or response is needed?

Integration

Name the two types of cells that compose nervous tissue.

Neurons and neuroglia

Which excitable cells conduct electrical signals over long distances?

Neurons

Neurons belong to what general category of cells based on their ability to release substances?

Secretory cells

What is another name for neuroglial cells?

Glia or glial cells

What is the primary function of neuroglial cells?

To support and assist neurons

The word “glia” literally means what?

Glue

List the three hallmark characteristics of neurons.

Excitability (ability to generate action potentials), conductivity, and secretion

Neurons can convert a stimulus into which electrical signal?

An action potential

By what means do neurons carry action potentials throughout the body?

Via electrical signals along their membranes

How do neurons communicate with other neurons across a synapse?

By releasing (secreting) neurotransmitters

Do mature neurons undergo mitosis?

No, they are amitotic

What term describes the ability of other body parts to learn the functions of damaged nervous tissue?

Plasticity

Approximately how long can neuron cells live?

About 100 years or more

What are the three functional classes of neurons?

Sensory neurons, interneurons, and motor neurons

What is the role of sensory neurons?

They bring impulses from the external environment to the CNS

Sensory neurons are classified as afferent or efferent transmitters?

Afferent

Which type of neuron is found only within the CNS and connects sensory neurons to motor neurons?

Interneurons

Which neurons send responses from the CNS out to other parts of the body?

Motor neurons

Motor neurons are classified as afferent or efferent?

Efferent

Name the two basic structural components of a neuron.

The soma (cell body) and its processes

What are the two types of processes that extend from the neuron’s soma?

Dendrites and an axon

List four key organelles located within the neuron’s soma (cell body).

Nucleus, Golgi complex, mitochondria, and extensive rough endoplasmic reticulum

Which structures organize rough ER into compartments/cages inside the soma?

Neurofibrils (actin filaments)

What term refers to rough ER that has been sorted and organized into compartments within a neuron?

Chromatophilic substance

Describe the general structure of dendrites.

Generally short, tapering extensions of the soma

In reference to dendrites, what does “tapering” mean?

They are wider near the soma and become narrower farther away

Which region of the neuron is formed by the dendrites?

The receptive region

What is the primary function of dendrites?

To convey local (short-distance) potentials toward the cell body

Are dendrites afferent or efferent in terms of signal direction?

Afferent

How many axons does a typical neuron possess?

One

What is the specialized area called where an axon attaches to the soma?

The axon hillock

Describe the general structure of an axon.

Cylindrical and non-tapering

What is the region at the distal end of an axon called?

The axon terminal

What is the main function of the axon terminal?

Secretion of neurotransmitter-filled vesicles to excite or inhibit the next cell

Which region of the neuron is constituted by the axon terminal?

The conducting region

Is signaling at the axon terminal afferent or efferent?

Efferent

On what criterion are neurons structurally classified?

The number of processes extending from the soma

Name the three structural types of neurons.

Multipolar, unipolar, and bipolar

How many processes does a multipolar neuron have?

Multiple: one axon and hundreds to thousands of dendrites

Which structural type of neuron makes up the majority of neurons in the CNS?

Multipolar neurons

Functionally, multipolar neurons act as what two classes?

Motor neurons and interneurons

How many processes does a unipolar neuron have?

One process that branches into an axon with dendrites

Functionally, unipolar neurons are classified as what?

Uniquely sensory

Where are bipolar neurons typically found in the body?

Primarily in special senses such as the retina of the eye and the olfactory epithelium