Mnb - M2N Ch 2

Front 1

with rare exception, each neuron has a _______ axon

Back 1

with rare exception, each neuron has a single axon

Front 2

axons appear first during neuronal _______

Back 2

axons appear first during neuronal differentiation

Front 3

axons initial segments are distinguished by a specialized plasma membrane containing a high density of _______ and distinctive _______ organization

Back 3

axons initial segments are distinguished by a specialized plasma membrane containing a high density of ion channels and distinctive cytoskeletal organization

Front 4

axons typically are cylindrical in form with a round or elliptical _______

Back 4

axons typically are cylindrical in form with a round or elliptical cross section

Front 5

large axons are _______ in vertebrates, and the thickness of the _______ is proportional to the axonal caliber

Back 5

large axons are myelinated in vertebrates, and the thickness of the myelin sheath is proportional to the axonal caliber

Front 6

Axon caliber is a function of _______ and _______ numbers with _______ predominating in large axons

Back 6

Axon caliber is a function of neurofilament and microtubule numbers with neurofilaments predominating in large axons

Front 7

_______ in axons have a uniform polarity with plus ends distal from the cell body

Back 7

Microtubules in axons have a uniform polarity with plus ends distal from the cell body

Front 8

Axon microtubules are enriched in _______ with a characteristic phosphorylation patter

Back 8

Axon microtubules are enriched in tau protein with a characteristic phosphorylation patter

Front 9

_______ are excluded from mature axons, although a few may be detectable in initial segments

Back 9

ribosomes are excluded from mature axons, although a few may be detectable in initial segments

Front 10

axonal branches tend to be _______ from the cell body

Back 10

axonal branches tend to be distal from the cell body

Front 11

axonal _______ form obtuse angles and have diametes similar to the parent stem

Back 11

axonal branches form obtuse angles and have diametes similar to the parent stem

Front 12

Most axons have _______ that may be en passant or at the ends of the axonal branches

Back 12

Most axons have presynaptic specializations that may be en passant or at the ends of the axonal branches

Front 13

action potentials are usually generated at the _______ and conducted away from the cell body

Back 13

action potentials are usually generated at the axon hillock and conducted away from the cell body

Front 14

tranditionally, axons are specialized for _______ and _______, ie, neuronal output

Back 14

tranditionally, axons are specialized for conduction and synaptic transmission, ie, neuronal output

Front 15

most neurons have multiple _______ arising from their cell bodies

Back 15

most neurons have multiple dendrites arising from their cell bodies

Front 16

dendrites begin to _______ only after the axon has formed

Back 16

dendrites begin to differentiate only after the axon has formed

Front 17

Dendrites are continuous with the _______, and the transition point cannot be distinguished readily

Back 17

Dendrites are continuous with the perikaryal cytoplasm, and the transition point cannot be distinguished readily

Front 18

Dendrites usually have significant _______ and small spinous processes that give them an irregular cross section

Back 18

Dendrites usually have significant taper and small spinous processes that give them an irregular cross section

Front 19

dendrites are not _______, although a few wraps of _______ may occur rarely

Back 19

dendrites are not myelinated, although a few wraps of myelin may occur rarely

Front 20

The dendritic _______ may appear less organized, and _______ dominate even in large dendrites

Back 20

The dendritic cytoskeleton may appear less organized, and microtubules dominate even in large dendrites

Front 21

_______ in proximal dendrites have mixed polarity, with both plus and minus ends oriented distal to the cell body

Back 21

Microtubules in proximal dendrites have mixed polarity, with both plus and minus ends oriented distal to the cell body

Front 22

dendrites microtubules may contain some _______, but _______ is not present in axonal compartments and is highly enriched in dendrites

Back 22

dendrites microtubules may contain some tau protein, but MAP2 is not present in axonal compartments and is highly enriched in dendrites

Front 23

Both_______ and _______ are present in dendrites, with specific mRNAs bein enriched in dendrites

Back 23

Both rough endoplasmic reticulum and cytoplasmic polysomes are present in dendrites, with specific mRNAs bein enriched in dendrites

Front 24

Dendrites begin to branch extensively near the _______ and form extensive arbors in the vicinity of the _______

Back 24

Dendrites begin to branch extensively near the perikaryon and form extensive arbors in the vicinity of the perikaryon

Front 25

dendritic branches form acute angles and are smaller than the present stem

Back 25

dendritic branches form acute angles and are smaller than the present stem

Front 26

dendrites are rich in _______, particularly on the _______ that project from the dendritic shaft

Back 26

dendrites are rich in postsynaptic specializations, particularly on the spines that project from the dendritic shaft

Front 27

dendrites may generate action potentials, but more commonly they modulate the_______ of perikaryon and initial segment

Back 27

dendrites may generate action potentials, but more commonly they modulate the electrical state of perikaryon and initial segment

Front 28

Dendritic architecture is most suitable for integrating _______ responses from a variety of inputs, ie, neuronal input

Back 28

Dendritic architecture is most suitable for integrating synaptic responses from a variety of inputs, ie, neuronal input

Front 29

TUBULIN: alpha- and beta-TUBULIN

Back 29

"neurons, glia, and nonneuronal cells except mature mammalian erythrocytes.

Multigene family with some genes expressed preferentially in brain, whereas others are ubiquitous.

Primary structural polypeptides of microtubules"

Front 30

peptide vs polypeptide

Back 30

"A peptide comprising ten or more amino acids.

Polypeptides that constitute proteins usually contain 100–300 amino acids"

Front 31

gamma-TUBULIN

Back 31

"present near microtubule-organizing center in all microtubule-containing cells.

Needed for nucleation of microtubules (make new)"

Front 32

"Microtubule-associated proteins (MAPs)

MAP1a/1b"

Back 32

Widely expressed in neurons and glia, including both axons and dendrites; developmentally regulated phosphoproteins

Front 33

"Microtubule-associated proteins (MAPs)

MAP2a/2b, MAP2c"

Back 33

"Dendrite-specific MAPs.

The smaller MAP2c is regulated developmentally, becoming restricted to spines in adults, whereas 2a and 2b are major phosphoproteins in adult brain."

Front 34

"Microtubule-associated proteins (MAPs)

LMW tau HMW tau"

Back 34

Tau proteins are enriched in axons with a distinctive phosphorylation pattern. A single tau gene is alternatively spliced to give multiple isoforms.

Front 35

"Microtubule-severing proteins

Katanin"

Back 35

Enriched at the microtubule-organizing center and thought to be important in the release of microtubules for transport into axons and dendrites

Front 36

"Motor proteins

Kinesins (kinesin-1s, kinesin-2s, kinesin-3s, and others)"

Back 36

"Kinesin-1s are plus-end directed motor associated with membrane-bound organelles and moving them in fast axonal transport.

The other members of the kinesin family are a diverse set of motor proteins with a kinesin-related motor domain and a varied tails.

Many are regulated developmentally, and some are mitotic motors, restricted to dividing cells."

Front 37

"Motor proteins

Axonemal dynein"

Back 37

A set of minus-end-directed microtubule motors associated with cilia and flagella, such as ependymal cells.

Front 38

"Motor proteins

Cytoplasmic dynein"

Back 38

Cytoplasmic forms may be involved in the axonal transport of either organelles or cytoskeletal elements

Front 39

Motor proteins

Back 39

Motor proteins are a class of molecular motors that are able to move along the surface of a suitable substrate. They are powered by the hydrolysis of ATP and convert chemical energy into mechanical work.

Front 40

tubulins

Back 40

"Tubulin is one of several members of a small family of globular proteins. The most common members of the tubulin family are α-tubulin and β-tubulin, the proteins that make up microtubules. Microtubules are assembled from dimers (a chemical structure formed from two sub-units) of α- and β-tubulin.

To form microtubules, the dimers of α- and β-tubulin bind to GTP and assemble onto the (+) ends of microtubules while in the GTP-bound state. After the dimer is incorporated into the microtubule, the molecule of GTP bound to the β-tubulin subunit eventually hydrolyzes into GDP through inter-dimer contacts along the microtubule protofilament. Whether the β-tubulin member of the tubulin dimer is bound to GTP or GDP influences the stability of the dimer in the microtubule.

Dimers (a chemical structure formed from two sub-units) bound to GTP tend to assemble into microtubules, while dimers bound to GDP tend to fall apart; thus, this GTP cycle is essential for the dynamic instability of the microtubule."

Front 41

Microtubule-associated protein

Back 41

"microtubule-associated proteins (MAPs) are proteins that interact with the microtubules of the cellular cytoskeleton.

MAPs bind to the tubulin subunits that make up microtubules to regulate their stability.

Other functions: These include both stabilizing and destabilizing microtubules, guiding microtubules towards specific cellular locations, cross-linking microtubules and mediating the interactions of microtubules with other proteins in the cell "