Review of Cellular Neuroanatomy

Question 1

What are glia

Answer 1

They provide physical support to neurons (the other of the two principal cell types in the nervous system).
Also provide electrical insulation for impulse conductance
Provide metabolic exchange between the the vascular system and the Nervous sytem

Question 2

Cell Body of a Neuron called?

Answer 2

Soma

Question 3

Name the two types of processes that extend from a soma?

Answer 3

Axon and Dendrites

Question 4

Electrical input for the cell comes trhough?

Answer 4

Dendrites

Question 5

Electrical output for a cell comes through

Answer 5

Axon

Question 6

Gray Matter =

Answer 6

unmyelinated tissue

Primaruly somas and dendrites

Question 7

White matter=

Answer 7

tissue containing myelinated axons

Question 8

Myelin=

Answer 8

lipid wrapping on axons

Question 9

Soma of Neurons is especially rich in what cell organelle?

Answer 9

rER…because of the large amount of proteins it produces

Question 10

What stain is used to look for Neuronal somas and proximal dendrites

Answer 10

A Nissl stain

Question 11

What is a Nissl stain

Answer 11

A stain which preferentially stains Nissl substance made up of Nissl bodies…basophillic mass that is made up primarily of rER and ribosomes (protein synthesis bundles).

Question 12

Nissl stain typically stains what parts of a neuron?

Answer 12

Cell body (stroma) and proximal dendrites…does not extend into the axon

Question 13

rER stacks appear as islands in the Nissl stain

Answer 13

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Question 14

Axons usually form where?

Answer 14

the soma at the axon hillock specifically

Question 15

What is the axon Hillock

Answer 15

An area that is free of cell organelles. The beginning of an axon.

Question 16

Axonal initial segment is?

Answer 16

The area of the axon that originates at the hillock and goes to the beginning of the myelination line

Question 17

What are dendritic spines?

Answer 17

Places where dendrites receive information from other Neurons via synapses. This is especially true for excitatory inputs

Question 18

Which part of the axon is generally the site of action potential initiation?

Answer 18

Axonal initial segment

Question 19

What are axon collaterals

Answer 19

major branches of an axon

Question 20

Neurons whose axons contact muscle or glands are known as?

Answer 20

motor neurons

Question 21

Neurons are classified based on what?

Answer 21

Dendritic structure (number and pattern of dendrites)

Question 22

What are principal cells

Answer 22

Projection neurons, meaning they integrate information and send axons to other brain areas.

Question 23

Golgi Type 1 cells are

Answer 23

Principal cells…just means they have a long projection axon

Question 24

Interneurons are

Answer 24

cells that do not send their axon out of the local brain area. Also called local circuit neurons

Question 25

Interneurons are also classified as

Answer 25

Golgi Type 2 cells

Question 26

Synapses are

Answer 26

specialized junctions that allow neural signals to be communicated from one cell to another

Question 27

Two types of synaptic transmissions and they are?

Answer 27

Chemical and Electrical

Question 28

Electrical synapses are formed as direct connections from one cell to another via gap junctions.

Answer 28

ok

Question 29

Chemical synapses = electrical signal in the presynaptic neuron is transduced into release of a chemical transmitter that traverses a synaptic cleft to bind to receptors on the postsynaptic neuron

Answer 29

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Question 30

Synapses classified how?

Answer 30

By their subcellular target (axosomatic - synapse between axon and soma)

Question 31

Most excitatory synapses are what

Answer 31

formed on dendritic spines...called axospinous

Question 32

Vertebrate chemical synapses are

Answer 32

Unidirectional...they only transmit info from the presynaptic neuron to the postsynaptic

Question 33

Know the pattern of sending a signal via a synapse

Answer 33

1) The presynaptic bouton contains membranous synaptic vesicles that contain neurotransmitter 2) On an incoming nerve impulse, the entry of calcium causes synaptic vesicles to release their contents into the synaptic cleft 3) Specialized receptor proteins located in the postsynaptic density bind the neurotransmitter and generate another electrical signal in the postsynaptic cell.

Question 34

On the basis of their function, neurotransmitters can be divided into three classes:

Answer 34

excitatory- these types of synapses increases the probability that the postsynaptic neuron will fire an action potential. Examples are synapses containing acetylcholine ( at nicotinic receptors) or glutamate inhibitory- reduces the probability that the postsynaptic neuron will fire an action potential. Examples are synapses with glycine or GABA modulatory - influences how excitatory and inhibitory signals are integrated.

Question 35

Excitatory means Inhibitory means

Answer 35

something that increases the probability of an action potential Inhibitory means something that decreases the probability for an action potential

Question 36

Gray's type 1 synapse

Answer 36

Excitatory

Question 37

Gray's type 2 synapse

Answer 37

Inhibitory

Question 38

Gray's type 1 synapses (excitatory) are found mostly on what?

Answer 38

Dendrites

Question 39

Type II synapses (inhibitory) are found where?

Answer 39

Somas mostly

Question 40

In electrical synapses, passive flow of electrical current from one cell to the next is achieved via?

Answer 40

Gap junctions

Question 41

Gap junctions are made up of what

Answer 41

Connexons (6 connexins make a connexon). These pores form a connection between the cytoplasm of two opposing cells

Question 42

ELectrical synapses can be bi-directional

Answer 42

whereas chemical synapses are uni-directional

Question 43

How are proteins made in the soma transported out of the soma and through processes (axons and dendrites)

Answer 43

- Packed into cargo vesicles and transported along microtubules toward their destination via ratchet-like action. - Remember, there are separate engines for movement to the soma and away from the soma - To the soma= Dynein...moves vesicles retrograde (to the soma) - Away from the soma (anterograde)- Kinesin

Question 44

Schwann cells do what?

Answer 44

Provide myelination in the PNS

Question 45

Oligodendrocytes do what

Answer 45

myelination in the CNS

Question 46

Astrocytes do what

Answer 46

Provide general support and serve as part of the blood brain barrier in the CNS.

Question 47

Two types of astrocytes are?

Answer 47

Fibrous: | Protoplasmic

Question 48

Microglia do what?

Answer 48

They mediate phagocytosis and response to inflammation in the CNS... The immune cells of the brain

Question 49

Schwann cells, oligodendrocytes, astrocytes, and microglia are all what type of cells

Answer 49

Neuroglia----supporting cells

Question 50

Schwann cells provide myelination in the PNS. Myelination does what

Answer 50

electrical insulation

Question 51

Node of Ranvier is what?

Answer 51

The area in between two schwann cells...an unmyelinated area. This is the area where action potentials regenerate

Question 52

Endoneurium

Answer 52

Thin connective tissue layer that surrounds each nerve fiber

Question 53

Perineurium

Answer 53

Surrounds the nerve fascicle itself

Question 54

One oligodendrocytes has several processes and each process myelinates one axon, therefore one oligodendrocyte myelinates several axons

Answer 54

know

Question 55

Astrocytes do what

Answer 55

move metabolites to and from neurons

Question 56

Perineural feet? Perivascular feet

Answer 56

processes from astrocytes that make ocntact with neurons processes from astrocytes that make contact with blood vessels and myelin

Question 57

What are satellite cells

Answer 57

small cuboidal cells of neural crest origin....function as the astrocytes of teh PNS

Question 58

Ependymal cells

Answer 58

Line the ventricles of the braina nd the central canal of the spinal cord...cells are often cilliated and form simple cuboidal or low columnar epithelium.