Synapse I

Question 1

A synapse is a specialized ______ between neurons at the end of an _____

Answer 1

junction; axon

Question 2

Synapses are considered _____ (presynaptic/postsynaptic)

Answer 2

directional

Question 3

Synapses convert action potentials into a ____ signal, also known as a ______

Answer 3

chemical; neurotransmitter

Question 4

Synaptic _____ contain neurotransmitters and the action potential causes them to fuse with the ___-synaptic membrane

Answer 4

vesicles; pre

Question 5

Neurotransmitters are released into the _________ which is the space between the neurons via action potenital

Answer 5

synaptic cleft

Question 6

The transmitter binds to _____ (proteins) in which membrane?

Answer 6

receptors; postsynaptic

Question 7

Binding of transmitters to receptors first opens the ____, then activates the _____ and lastly causes a response in the ___-synaptic neuron.

Answer 7

ion channel; enzyme; post

Question 8

Each neuron typically receives 1k-10k synapses, although most are located on the ____

Answer 8

dendrites

Question 9

An action potential opens ____ gated ____ channels in the axon terminal.

Answer 9

voltage; calcium

Question 10

Calcium influx causes what structure to fuse with the presynaptic membrane, causing neurotransmitter release into the synaptic cleft?

Answer 10

synaptic vesicles

Question 11

Neurotransmitters bind to which receptor?

Answer 11

postsynaptic

Question 12

If the receptor is an ion channel, the channel ____, ions flow ___ the postsynaptic neuron, and causes postsynaptic _____.

Answer 12

opens; into; potential

Question 13

Vesicles are recycled, meaning that new vesicles bud off from which membrane? What is this process called?

Answer 13

presynaptic; endocytosis

Question 14

Neurotransmitters are synthesize locally where?

Answer 14

in the axon terminal

Question 15

Neurotransmitters are loaded into vesicles by _____ proteins and into the ___ membrane.

Answer 15

transport; vesicular

Question 16

What is the difference between ionotropic and metabotropic?

Answer 16

ionotropic = opens ion channel

metabotropic = g-protein coupled, causes production of 2nd messenger, activates kinase –> modifies proteins

Question 17

Which type of synapse opens ion channels?

Answer 17

ionotropic

Question 18

Which type of synapse use signal transduction mechanisms such as g-proteins?

Answer 18

metabotropic

Question 19

Protein kinases modify the function of many different proteins that change what about the neurons?

Answer 19

their electrical excitability

Question 20

What are the 2 main types of postsynaptic potentials?

Answer 20

EPSP: excitatory
IPSP: inhibitory

Question 21

What does a EPSP do?

Answer 21

depolarize the neuron (more likely to fire an action potential)

Question 22

What does an IPSP do?

Answer 22

hyperpolarize the neuron (less likely to fire an action potential)

Question 23

Which type of postsynaptic potential will be more likely to fire an action potential?

Answer 23

EPSP

Question 24

A neuromuscular junction is a synapse from a ____ neuron onto a ___ fiber

Answer 24

motor; muscle

Question 25

What is the neurotransmitter released at the neuromuscular junction?

Answer 25

ACh (Acetylcholine)

Question 26

ACh is synthesized by which neurotransmitter in the axon terminal?

Answer 26

ChAT (choline acetyltransferase)

Question 27

Acetylcholinesterase (AChE) in the synaptic cleft degrades ACh into ____ and ____

Answer 27

acetate; choline

Question 28

What is pumped into the presynaptic terminal?

Answer 28

Choline

Question 29

What is pumped into the vesicle by the vesicular transporter (VAChT)?

Answer 29

ACh

Question 30

What type of synapse is the NMJ?

Answer 30

ionotropic

Question 31

What is the name of the nonselective cation permeable channel?

Answer 31

Nicotinic cholinergic ACh receptors

Question 32

Binding of what opens the channels at the NMJ?

Answer 32

2 ACh molecules

Question 33

Influx of _____ dominates the efflux of ____ which causes the membrane potential to be more negative at rest.

Answer 33

Na+; K+

Question 34

Excitatory action ____ the muscle cell

Answer 34

depolarizes

Question 35

Myasthenia Gravis (MG) is an autoimmune disorder in which antibodies attack what important receptors at the NMJ?

Answer 35

Nicotinic ACh

Question 36

What are the common signs and symptoms of Myasthenia Gravis?

Answer 36

1. Muscle Weakness 2. Cranial Nerves 3. Ptosis (eyelids) 4. Extra-occular Eye Muscles (eye movements)

Question 37

What serious problem can Myasthenia Gravis lead to?

Answer 37

Respiratory Failure

Question 38

How does the Tensilon (the drug edrophonium) Test aid in diagnosing Myasthenia Gravis?

Answer 38

Tensilon prevents the breakdown of the chemical acetylcholine, a neurotransmitter that nerve cells release to stimulate your muscles. People with the chronic disease myasthenia gravis don’t have normal reactions to acetylcholine. Antibodies attack their acetylcholine receptors. This prevents muscles from being stimulated and makes muscles easy to tire. A person tests positive for myasthenia gravis if their muscles get stronger after being injected with Tensilon.

Question 39

What is Lambert-Eaton Syndrome (LEMS)?

Answer 39

An autoimmune disorder in which antibodies attack voltage-gates calcium channels at the NMJ. The lowered amount of ACh causes muscle weakness due to the inability to contract the muscles as forcefully. Mainly affects the upper hip/legs especially when rising from a chair, and in the morning. Related to small-cell lung cancer

Question 40

MG antibodies attack ___-synaptic ____ receptors, whereas LEMS antibodies attack ___-synaptic ___ channels.

Answer 40

post; ACh pre; calcium

Question 41

MG is associated with _____ while LEMS is associated with _____

Answer 41

thymoma; small-cell lung cancer

Question 42

In MG, muscles are ____ with repetition, whereas in LEMS, muscles are ____ with repetition.

Answer 42

weaker; stronger

Question 43

MG affects the body more towards the ____ whereas LEMS affects the body especially in the _____

Answer 43

end of the day; morning

Question 44

Respiratory and ocular muscle involvement is not as severe in ____ as it is in ____

Answer 44

LEMS; MG

Question 45

NMJ drugs are used to ___ and/or ___ the NMJ

Answer 45

block; enhance

Question 46

Blocking the NMJ may be used in instances such as surgery and intubation because it causes temporary what?

Answer 46

paralysis

Question 47

Enhancing the NMJ may be used in instances such as treatment of MG because it helps with what?

Answer 47

normal NMJ function

Question 48

NMJ blocking drugs include 2 types of agents, which are what?

Answer 48

1. Depolarizing Agent | 2. Non-depolarizing Agent

Question 49

A common depolarizing agent (NMJ Blocker) is Succinylcholine, which helps to block the NMJ by binding aggressively to and activating what?

Answer 49

Nicotinic ACh receptors

Question 50

If the nicotinic ACh receptors are activated via Succinylocholine, the muscle cells _____, voltage-gated __ channels open and then stay inactivated, causing it to be ____ resistant

Answer 50

depolarize; Na+; AChE

Question 51

Common non-depolarizing agents (NMJ blockers) are Mivacurium and Pancuronium. They are competitive _____ and displace ____ at the nicotinic ACh receptors in the NMJ but do NOT do what?

Answer 51

antagonists; ACh; do NOT open channels

Question 52

Common NMJ enhancing drugs include Cholinesterase (AChE) Inhibitors, such as edrophonium and physotigmine. These drugs work to enhance the NMJ by blocking ____ and increasing ____ at the cholinergic synapses

Answer 52

AChE; ACh