Neurobiology 2

Front 1

There are 5 steps in chemical transmission of neurotransmitters:

Back 1

Presynaptic:
1- Synthesis of neurotransmitter
2- Storage
3- Release

Postsynaptic
4- Neurotransmitter interacts with receptor in post synaptic membrane (effect)
5- Removal of NT from synapse

Front 2

________ is a substance produced and released at a synapse by one neuron that affects a postsynaptic cell in a specific manner.

Back 2

Neurotransmitter

Front 3

Storage of neurotransmitters occur in 2 places:

Back 3

1- Small synaptic vesicles

2- Large dense core vesicles

Front 4

_________ are located near active zone and contain ACh, Glutamate, GABA, Glycine

Back 4

Small synaptic vesicles

Front 5

________ are not near active zone and contain neuropeptides, dopamine, norepinephrine, and serotonin.

Back 5

Large dense core vesicles

Front 6

Small vesicles are released with _________

Back 6

low stimulation.

Small clear vesicles are released by local increases in Ca2+

Front 7

__________ can lead to release of dense core vesicles. Release depends on general Ca2+ levels.

Back 7

High-frequency stimulation

Front 8

The 4 types of major transmitters are:

Back 8

1- Acetylcholine

2- Biogenic amines

3- Amino acids

4- Peptides (neuropeptides)

Front 9

Acetylcholine, biogenic amines, and amino acids are characterized as ________

Back 9

small molecules

Front 10

Norepinephrine, dopamine, epinephrine, and serotonin are __________

Back 10

biogenic amines

Front 11

Glutamate, Gamma amino butryric acid (GABA), and Glycine are ________

Back 11

Amino acids

Front 12

Cholecystokinin, endorphin, dynorphin, enkephalin, neuropeptide Y, somatostatin, substance P, and vasoactive intestineal pepite are ___________

Back 12

Pepties.

Front 13

________ is the only small XMTR that is not an amino acid or that is derived from one.

Back 13

Acetylcholine

Front 14

Acetylcholine (ACh) is synthesized from ________ and _______ by the enzume choline acetyltransferase

Back 14

Choline (which we get from eggs, spinach, and liver) and acetyl CoA

Front 15

In the synaptic cleft, ACh is rapidly broken down by the enzyme __________

Back 15

acetylcholinesterase

Front 16

ACh is stored in _________

Back 16

small vesicles

Front 17

The 3 effects of ACh on postsynaptic cell are:

Back 17

1- Excitatory

2- Ionotropic Receptors - Nicotinic

3- Metabotropic receptors - Muscarinic - Only in CNS

Front 18

Removal of ACh is done by _________

Back 18

degradation by Acetylcholinesterase (AChE) which is found in postsynaptic membrane

Front 19

_________ receptor is the neuromuscular junction, found in muscle

Back 19

Nicotinic

Front 20

_________ receptor is found in heart, smooth muscles, and brain.

Back 20

Muscarinic

Front 21

The 4 drug actions that prevent acetylcholine are:

Back 21

1- Botulinis toxin - blocks ACh release from presynaptic terminal

2- ACh receptor competitor (ex. Curare: Deadshot used this in Arrow!)

3- AChE inhibitor (ex. Neostigmine)

4- Block reuptake of choline into presynaptic terminal (ex. hemicholinium)

Front 22

Catecholamines and Indolamines are types of ________

Back 22

biogenic amines

Front 23

Norepinephrine, dopamine, and epinephrine are types of _______ biogenic amines

Back 23

catecholamines

Front 24

Serotonin (5-HT) and melatonin are types of _________ biogenic amines

Back 24

Indolamines

Front 25

The two enzymes for removal of catecholamine biogenic amines are:

Back 25

1- Catechol-O-methyltransferase (COMT)

2- Monamine oxidase (MAO)

Front 26

Synthesis of catecholamine biogenic amines begin with:

Back 26

tyrosine hydroxylase

Front 27

Norepinephrine is part of the autonomic nervous system (flight or fight) and is synthesized by the same origin as other catchecolamines: tyrosine converted by ___________.

Back 27

Tyrosine hydroxylase

Dopamine beta hydroxylase is required enzyme

Front 28

Storage of norepinephrine is in ________

Back 28

large, dense core vesicles

Front 29

Effects of norepinephrine on postsynaptic cell are:

Back 29

1- EPSP or IPSP, depends on postsynaptic properties.

2- Receptors are always METABOTROPIC (G protein coupled)

Front 30

The 3 methods of removal for norepinephrine are:

Back 30

1- Reuptake into presynaptic cell via NE transporter (degraded by monoamine oxidase. Reuptake into synaptic vesicles)

2- Diffusion into vascular system (Degraded by MAO or catechol-o-methyl transferase (COMT)

3- Inactivation in synaptic cleft (COMT)

Front 31

_______ requires DOPA decarboxylase and has CNS role in neurotransmission and nonneural function in systemic role in regulation of blood flow and urine formation.

Back 31

Dopamine

Front 32

The CNS role dopamine plays in neurotransmission has 4 effects:

Back 32

1- Movement (Parkinson's Disease)

2- Mood (emotions, motivation, schizophrenia)

3- Cognition, memory

4- Inhibitor of prolactin secretion from pituitary

Front 33

Dopamine has similar uptake (with Dopamine transporter = _________), distribution, and elimination as other catecholamines.

Back 33

DAT

Front 34

The synthesis of serotonin has _________ as a precursor and has two enzymes needed for synthesize that drugs can antagonize.

Back 34

trytophan

Front 35

The 3 effects serotonin has on postsynaptic cell are:

Back 35

1- Can act on at least 9 different receptor subtypes

2- Majority are metatropic

3- Drugs can act to block reuptake, increase release

Front 36

Serotonin is found in ______ and ________

Back 36

brain and GI tract

Front 37

__________ is involved in mood, attention, cognition, and sleep

Back 37

Serotonin

Front 38

_________ is made from serotonin

Back 38

melatonin

Front 39

The serotonin transporter is _______

Back 39

SERT

Front 40

The amino acid neurotransmitter glutamate has a _____ effect.

Back 40

Excitatory

Front 41

The amino acid neurotransmitter glycine has a ________ effect

Back 41

Inhibitory

Front 42

The amino acid neurotransmitter GABA has a _________ effect

Back 42

Inhibitory

Front 43

Glutamate is found widely in CNS and is synthesized from _______

Back 43

glutamine

Front 44

Glutamate is stored in _________

Back 44

small vesicles

Front 45

The effect of glutamate is:

Back 45

1- Major excitatory XMTR!

Binds to at least 4 receptors (both metabotropic and nicotinic)

Front 46

Glutamate is removed in 3 ways:

Back 46

1- Uptake by glia

2- Reconverted to glutamine

3- Returned to neuron

Front 47

The two types of EPSPs in postsynaptic cell that glutamate generates are:

Back 47

1- Fast chemical synaptic transmission

2- Slow chemical synaptic transmission

Front 48

In fast chemical synaptic transmission of glutamate, there are _________ GLU receptors, such as NMDA receptor (Ca2+ and Na+) and AMPA/Kainate receptor (Na+).

Back 48

Ionotropic

Front 49

In slow chemical synaptic transmission of glutamate, there are __________ GLU receptors which are G-protein coupled. These increase Gca and Gna via second messenger systems = __________.

Back 49

Metabotropic

Ion conductance

Front 50

Glycine is synthesized from ________, and is found in spinal cord and brain stem.

Back 50

serine

Front 51

Glycine is a ___________ transmitter. It increases Cl-conductance, postsynaptic cell is hyperpolarized (opens Cl-ion channels)

Back 51

Inhibitory

Front 52

Glycine is removed by:

Back 52

taken up by glia and presynaptic cell

Front 53

GABA is synthesized from ________ which is converted into glutamate.

Back 53

glucose

Front 54

_________ is widely distributed in CNS. In spinal and cortical interneurons, Purkinje Cells in cerebellum, Amacrine cells in retina, and granule cells in olfactory bulb.

Back 54

GABA

Front 55

GABA is stored in ________

Back 55

small vesicles

Front 56

GABA is removed by:

Back 56

Taken up by glia and presynaptic cell

OR

degraded by enzymes

Front 57

The effect of GABA is _______

Back 57

Inhibitory

Front 58

In fast chemical synaptic transmission of GABA, The GABAa receptor is ______ and is a Cl- channel. Leads to hyperpolarization of post-synaptic cell. Benzodiazapeine and barbiturates act on these receptors.

Back 58

ionotropic

Front 59

In slow chemical synaptic transmission of GABA, GABAb receptor is _________. G-protein directly linked to K+ channels - no second messenger involvement. Increases K+ conductance = hyperpolarizes post-synaptic cell.

Back 59

Metabotropic

Front 60

Neuropeptides are synthesized on __________, located in cell body.

Back 60

ribosomes

Front 61

Neuropeptides are transported to terminals by ___________

Back 61

axonal transport.

Slow process.

Front 62

The central nervous system commands the muscles to move via ___________

Back 62

motor neurons (motoneurons)

Front 63

There are 2 types of motor neurons:

Back 63

1- Somatic motor neurons

2- Visceral motor neurons

Front 64

_________ motor neurons take input from the CNS (cell bodies in spinal cord, brain stem) to organs, cardiac muscle, smooth muscle.

Back 64

Visceral

Front 65

There are 2 types of somatic motor neurons:

Back 65

1- Alpha motor neurons

2- Gamma motor neurons

Front 66

___________ motor neurons innervate the skeletal muscles; main force-generating muscles.

Back 66

Alpha

Front 67

_______ motor neurons innervate the stretch sensing organ within a muscle (muscle spindle).

Back 67

Gamma

Front 68

In general, when talking about motor neurons, we are referring to _______ motor neurons.

Back 68

Alpha

Front 69

___________ is a single motor neuron with multiple terminals which synapse on individual muscle cells.

Back 69

Motor unit

Front 70

Muscle cells = _______

Back 70

muscle fibers (myofibers/myocytes)

Front 71

1 motor neuron innervates ___________

Back 71

multiple cells.

Front 72

Each muscle cell innervated by _____ motoneuron(s).

Back 72

1

Front 73

A group of muscle cells (myocytes) innervated by all the collaterals of a single presynaptic axon: _______

Back 73

motor neuron

Front 74

Muscle cell/axon ________ determines precision of control.

Back 74

Ratio.

In the eye, the ratio is 1:1

Front 75

Because a motor neuron can innervate multiple muscle cells, if a single motor neuron is damaged, there is _________ impact on the muscle.

Back 75

little

Front 76

In a motor unit, the fibers are scattered over a fairly large area of the muscle - thus the activity of a single motor unit is often observed _______

Back 76

grossly

Front 77

Motor units are related to muscle ___________

Back 77

contraction

Front 78

____________ has a small cell body, smaller axon and thus slower conducting axon, less fatiguable.

Back 78

Small motor unit

Front 79

__________ has large cell body, larger axon, transmits AP more quickly.

Back 79

Large motor unit

Front 80

CNS can increase the force of contraction by increasing number of motor units engaged at any one time = _________

Back 80

spatial summation

Front 81

CNS can increase the force of contraction by increasing frequency of activation of motor unit before it relaxed = ____________

Back 81

temporal summation

Front 82

CNS can regulate smoothness of contraction: recruits small units first, then larger units = ________

Back 82

precision

Front 83

__________ is all the motor neurons that innervate a single muscle.

Back 83

Motor neuron pool.

Front 84

4 things comprise a motor unit:

Back 84

1- One motor neuron (with multiple branches)

2- Terminals which synapse on

3- Muscle fibers

4- Myofibrils

Front 85

Alpha motor neurons can also be called _______________, in ventral horn of spinal cord.

Back 85

Lower motor neuron

Front 86

________ are integrators.

Back 86

Motor neurons

Front 87

Alpha motor neurons receive many synapses from multiple sources, both __________ and ________.

Back 87

excitatory and inhibitory

Front 88

3 examples of input that ___________ receive are input from spinal interneurons, sensory input from muscle spindles, and input from upper motor neurons in the brain.

Back 88

alpha motor neuron

Front 89

Motor neuron terminals synapse on muscle cells, called _____________

Back 89

neuromuscular junction

Front 90

The __________ has a synaptic structure similar to neuron-neuron synapse; containing a presynaptic axon, presynaptic membrane, synaptic cleft, and postsynaptic membrane (muscle cell)

Back 90

neuromuscular junction

Front 91

__________ provide the sole pathway by which the CNS activates movement through muscle contraction.

Back 91

Motor neurons

Front 92

When neuromuscular junctions synapse with smooth and cardiac muscle, _________ is the major transmitter. Also, there is gap junction coupling, mutiple cells per synapse, and ACh, serotonin, and other transmitters are present.

Back 92

Norepinephrine

Front 93

When neuromuscular junction synapse with skeletal muscle, ________ is the transmitter, and there is 1 synapse per cell.

Back 93

ACh.

Front 94

The ____________ is a muscle cell on the postsynaptic membrane on which the neuromuscular junction occurs.

Back 94

Motor endplate

Front 95

There are ________ folds in the motor endplate

Back 95

junctional

Front 96

The synaptic cleft of the neuromuscular junction is filled with mucopolysaccharide ______.

Back 96

"Glue"

Front 97

In the neuromuscular junction, the motor axon loses _________ and then it branches.

Back 97

Myelin sheath

Front 98

The muscle fiber in the neuromuscular junction is innervated at a specialized region called a ___________

Back 98

motor end-plate

Front 99

The varicosities in the neuromuscular junction is covered by a thin layer of ___________.

Back 99

Schwann cells.

Front 100

Each contact (varicosity) of the neuromusuclar junction serves as a synaptic ________.

Back 100

bouton.

The bouton releases ACh

Front 101

Neuromuscular junction has all the machinery necessary for neurotransmitter _________. Has voltage gated channels.

Back 101

release

Front 102

In the synaptic cleft of the neuromuscular junction, the pre and postsynaptic membranes are about _______ apart.

Back 102

100 nm

Front 103

Within the synaptic cleft, there is a structure called _____________. It is made of collagen and extracellular matrix proteins and forms an anchor for acetylcholinesterase.

Back 103

Basement membrane

Front 104

The ___________ on the postsynaptic cell contains ACh receptors and voltage gated channels.

Back 104

junctional folds

Front 105

_________ is released at NMJ.

Back 105

ACh

Front 106

The muscle receptor at the neuromuscular junction is a(n) __________ receptor. It is located at the crests of folds.

Back 106

nicotinic

Front 107

Motor neurons excite muscle by opening channels at the ___________ voltage gated Na+ channels.

Back 107

endplate

Front 108

ACh release leads to rapid _________ of the end plate.

Back 108

depolarization

Front 109

Normally called Excitatory Postsynaptic Potential (EPSP), in the neuromuscular junction, called ____________.

Back 109

Endplate Potential (EPP)

Front 110

The endplate potential has a ____mV depolarization.

Back 110

70

Front 111

The depolarization at neuromuscular junctions is caused by ionic current flowing through ______ gated channels. Initiates action potential, which propagates along muscle fiber.

Back 111

ACh

Front 112

The 7 stages of synaptic transmission at Cholinergic Neuromuscular synapse (innervation of skeletal muscle).

Back 112

1- AP arrives at presynaptic terminal.

- Ca2+ enters terminal

3- Docked vesicles dump XMTR, more docking, more dumping

4- ACh released into cleft

5- ACh diffuses to ionotropic receptors on postsynaptic membrane (motor endplate), Na+ rushes in.

6- Na+ influx leads to EPP in postsynaptic membrane (muscle). (Can then lead to AP).

7- Acetylcholinesterase breaks down ACh into choline and acetate. Channels close. Reuptake of ACh also occurs at presynaptic membrane.

Front 113

The synaptic potential of EPP increases _________ and decreases __________.

Back 113

Rapidly;

Slowly

Front 114

EPP has rapid rise due to sudden flood of ________ into cleft.

Back 114

ACh

Front 115

ACh diffuses rapidly through cleft to receptors on _________.

Back 115

endplate.

Front 116

Not all ACh reaches endplate, so these are removed by 2 ways:

Back 116

1- Diffusion out of cleft.

2- Inactivation by hydrolysis (AChE)

Front 117

EPP spreads __________ away from endplate.

Back 117

passively

Front 118

EPP change in membrane potential falls with distance from _______.

Back 118

endplate

(The further away from the endplate, the smaller the membrane potential change becomes.)

Front 119

EPP or EPSP:

Input from only one cell. Multiple synapses on endplate.

Back 119

EPP.

(EPSP has input from 1000s of neurons).

Front 120

EPP or EPSP:

Small postsynaptic potential. Single neuronal synapse < 1mV change in membrane potential.

Back 120

EPSP.

(EPP has large synaptic potential. Endplate potential = 70 mV change in membrane potential.)

Front 121

EPP or EPSP:

Functional diversity: Excitatory and inhibitory, transmitter diversity.

Back 121

EPSP.

(EPP has functional uniformity: excitatory, uses ACh).

Front 122

EPP or EPSP:

Releases excess amounts of transmitter.

Back 122

EPP.

(EPSP releases small amount of transmitter.)

Front 123

EPP or EPSP:

Integrating.

Back 123

EPSP.

(EPP is non-integrating (after motor neuron integrates)).

Front 124

Denervation __________ occurs when axon is destroyed = dismantling of neuromuscular junction. Happens in skeletal muscle, smooth muscle, and glands.

Back 124

hypersensitivity

Front 125

The 5 stages of denervation hypersensitivity:

Back 125

1- Muscle becomes hypersensitive to application of XMTR. (circulating XMTR).

2- Dispersal of XMTR receptors over muscle cell surface.

3- Lack of trophic factor normally released with XMTR (trophic kept receptors localized to endplate).

4- Thus you can stimulate at any spot on membrane.

5- Acetylcholinesterase remains at endplate site.

Front 126

With axon repair = _______ receptors migrate back to endplate.

Back 126

XMTR

Front 127

__________ is a two way street - trophic factors come from the muscle.

Back 127

Denervation