Cells of the Nervous System

Question 0

Phospholipid bilayer (membrane)

Answer 0

Polar “head” contains phosphate, nonpolar “tail” contains hydrocarbon
Surrounds the whole cell (separating inter- and intracellular fluid)
Heads are hydrophilic, tails are hydrophobic
Membranes are self-organized, and are not fixed (membrane fluidity)–allows us to insert proteins into the fluid membrane
Embedded proteins give neurons their special properties

Question 1

Neuron

Answer 1

The basic unit of the nervous system
Consists of a cell body, receptive extensions (dendrites) and transmitting extension (axon)
Come in many different varieties based on size, shape, function, chemistry, etc.

Question 2

Soma

Answer 2

Cell body
Region of the neuron defined by the presence of the cell nucleus
Receives and integrates inputs (with dendrites)

Question 3

Dendrite/dendritic arbor or tree

Answer 3

Along with cell body, receive and integrate inputs
Dendrites are really extensions of the soma
Can synthesize proteins (axons cannot)
Dendrites have dendritic arbors (tree-like, tapered extensions)

Question 4

Axon

Answer 4

A single extension from the nerve cell that carries nerve impulses from the cell body to other neurons
Conducts action potential
Like a water pipe, constant diameter throughout its length until getting to the axon terminals, which end in terminal boutons aka synaptic knobs aka synaptic terminals

Question 5

Axon hillock

Answer 5

A cone-shaped area from which the axon originates out of the cell body
The integration zone of the neuron
With initial segment, generates axon potential

Question 6

Axon collateral

Answer 6

A branch of an axon from a single neuron

Always leaves the axon at right angles

Question 7

Synapse

Answer 7

The tiny gap between neurons where information is passed from one to the other

Question 8

Presynaptic terminal arbor

Answer 8

??

Question 9

Presynaptic terminal, boutons, buttons, or knobs

Answer 9

Transmits to target cells

End of an axon or axon collateral which forms a synapse on a neuron or other target cells

Question 10

Synaptic vesicles

Answer 10

A small, spherical structure that contains molecules of neurotransmitter
Sacs of membranes that transmit chemicals (neurotransmitters)

Question 11

Neurotransmitter

Answer 11

The chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons

Question 12

Synaptic cleft

Answer 12

The space between the presynaptic and postsynaptic elements

Question 13

Synaptosome

Answer 13

Body of the synapse

Synapse = marriage; synaptosome = spouses

Question 14

Neurites (or processes)

Answer 14

Leave the cell body
Include dendrites and axons
A typical neuron has varying numbers of dendrites and a single axon

Question 15

Unipolar neuron

Answer 15

A nerve cell with a single branch that leaves the cell body and then extends in two directions
One is the receptive pole, the other end is the output zone

Question 16

Bipolar neuron

Answer 16

A nerve cell that has a single dendrite at one end and a single axon at the other end (space between dendrite and cell body, long linear cell)

Question 17

Multipolar neuron

Answer 17

A nerve cell that has many dendrites and a single axon (no space between dendrites and cell body–looks like stereotypical neuron)

Question 18

Central nervous system

Answer 18

The portion of the nervous system that includes the brain and the spinal cord

Question 19

Peripheral nervous system

Answer 19

The portion of the nervous system that includes all the nerves and neurons outside the brain and spinal cord

Question 20

Glia

Answer 20

Come in several different varieties
Allow for optimizing specialized functions
Five to ten times as many glia as neurons in the CNS
Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain

Question 21

Astrocytes

Answer 21

A star-shaped glial cell with numerous processes (extensions) that run in all directions
Most numerous glial cell
Form the supporting matrix of the nervous system
Fairly large
Serve various functions: carry substances to and from blood vessels to neurons and back, carry metabolic waste products from neurons back to the blood, form scar tissue in the case of injury
Important for regulating environment of neurons
Buffer extra-cellular fluid for neurons
Not always helpful, can be implicated in the development of toxins that kill neurons

Question 22

Microglia

Answer 22

Extremely small glial cells that remove cellular debris from injured or dead cells
The principle immune element of the brain (brain is immunologically privileged)
Serve as phages, attack things in the brain
Seem to be implicated in Alzheimers (killing neurons–microglia gone nuts, neurons get tagged for destruction)

Question 23

Oligodendroglia

Answer 23

Glial cells that form myelin in the central nervous system

One oligodendrocyte can myelinate multiple axons

Question 24

Schwann cells

Answer 24

The glial cell that forms myelin in the peripheral nervous system
Schwann cells can only make one section of myelin
Peripheral nerves do regenerate because Schwann cells provide myelin; central nerves do not

Question 25

Myelin Sheath

Answer 25

The fatty insulation around an axon, formed by glial cells, that improves the speed of conduction of nerve impulses

Question 26

Functions of neurons: reception and integration of inputs

Answer 26

Dendrites and soma

Question 27

Functions of neurons: generation of action potential (nerve impulse)

Answer 27

Axon hillock

Question 28

Functions of neurons: conduction of action potential

Answer 28

Axon

Question 29

Functions of neurons: synaptic transmission

Answer 29

Transmit information to target cell (neuron, muscle, gland)

nerve terminals