Cells of the Nervous System

Question 1

Cytoplasm

Answer 1

The clear inner fluid of neurons and other cells.

Question 2

Cell membrane

Answer 2

The semipermeable membrane that encloses the cytoplasm of neurons and other cells; the wall of the cell.

Question 3

Cell body

Answer 3

The metabolic center of the neuron; also called the soma.

Question 4

Dendrites

Answer 4

The short bushy fibers that branch out from the cell body; they constitute the major signal receiving area of the neuron.

Question 5

Axon

Answer 5

The single long fiber that extends from a neuron’s cell body; its function is to conduct neural signals from the cell body to other parts of the nervous system.

Question 6

Buttons (terminal)

Answer 6

The button-like terminal endings of the axon branches.

Question 7

Nucleus

Answer 7

The large spherical structure in the cytoplasm of every cell; it contains the genetic material; in neurons, it is located in the cell body.

Question 8

Endoplasmic reticulum

Answer 8

The system of rough plate-shaped membranous sacs in the cytoplasm of cells; its rough appearance stems from the fact that it is covered with ribosomes; in neurons, it is located in the cell body.

Question 9

Ribosomes

Answer 9

The structures on which each cell’s proteins are synthesized; ribosomes are attached to the rough endoplasmic reticulum.

Question 10

Golgi apparatus

Answer 10

Systems of smooth plate-shaped membranous sacs in the cytoplasm of cells; they package proteins and other molecules in small membrane sacs.

Question 11

Mitochondria

Answer 11

Structures of the cytoplasm that play a role in a cell’s respiration and in its production and use of energy.
Singular: mitochondrion

Question 12

Neurofilaments

Answer 12

Fine thread-like structures that form a matrix in the cytoplasm; they provide support for the cell membrane and maintain the shape of the neuron.

Question 13

Microtubules

Answer 13

Fine tubes that course through the neural cytoplasm; they provide routes for the transport of molecules within neurons.

Question 14

Neurotransmitter molecules

Answer 14

Molecules that are released from the buttons of active neurons and influence the activity of other cells.

Question 15

Synaptic vesicles

Answer 15

Membrane sacs that store neurotransmitter molecules ready for release near the presynaptic membrane; they are manufactured by the Golgi apparatus.

Question 16

Receptive area

Answer 16

The dendrites and cell body of a neuron; the area of a neuron that receives most of its synaptic input.

Question 17

Synapse

Answer 17

The narrow cleft between a terminal button of one neuron and the receptive membrane of another.

Question 18

Axon hillock

Answer 18

The cone-shaped structure between the cell body and axon; action potentials are generated in the first segment of the axon, adjacent to the axon hillock.

Question 19

Presynaptic membrane

Answer 19

The section of the button membrane that is adjacent to the synaptic cleft; the site from which neurotransmitter molecules are released into a synapse.

Question 20

Receptors

Answer 20

Molecules in the neuron cell membrane to which neurotransmitter molecules bind in key-in-lock fashion and, in so doing, induce signals in the neuron.

Question 21

Postsynaptic membrane

Answer 21

The section of the cell membrane of a postsynaptic neuron that is adjacent to the synaptic cleft; the postsynaptic membrane contains postsynaptic receptors.

Question 22

Dendritic spines

Answer 22

The tiny protuberances on dendrites that are the location of many dendritic synapses.

Question 23

Nodes of ranvier

Answer 23

The gaps between adjacent glial segments on a myelinated axon.

Question 24

Oligodendrocytes (O-li-go-DEN-dro-sites)

Answer 24

Glial cells that myelinate CNS axons.

Question 25

Schwann cells

Answer 25

Glial cells that myelinate PNS axons.