Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

z. Neuro Class > Neuromuscular Transmission ppt 7 > Flashcards

Neuromuscular Transmission ppt 7 Flashcards

1
Q

What is an NMJ?

A

Neuromuscular junction , the axons of motor neurons innervate skeletal muscle fibers.
The neuron intercept at the motor end plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are key features of a peripheral synapse?

A
  • Only one motor neuron innervates a muscle fiber,
  • Only excitatory input (no inhibitory input) is received by each muscle fiber,
  • Only one neurotransmitter (Ach) activates the muscle fibers
  • One kind of receptor channel (nicotinic acetylcholine receptor channel)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the key features of a central synapse?

A
  • More complex than that at the nerve-muscle synapse.

- Inhibitory as well as excitatory inputs to a central neuron.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is Myasthenia Gravis?

A

Is an autoimmune disease in which antibodies attack the Nicotinic Ach receptors.
Prevents the Muscle Contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the typical symptom of myasthenia graves?

A

muscle weakness that increases during periods of activity and improves after periods of rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Myasthenia graves is usually associated with

A

underlying thymoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a Tension test?

A

A test fo MG

Administration of edrophonium, a short acting AchE inhibitor, rapidly improves symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is abnormally elevated in patients with MG?

A 
ACh antibodies. 
AntiMuSK antibody (30-40%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the treatment for MG?

A

AChE inhibitors

Thymectomy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Lambert Eaton syndrome (LEMS)?

A

-Auto immune disease in which antibodies attack calcium channels in the PRESYNAPTIC terminal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the typical symptoms of LEMS?

A
  • Weakness of proximal arms and legs
  • Affects the legs more than the arms.
  • Difficulties climbing stairs and rising from a sitting position
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

LEMS is usually associated with

A

small cell lung cancer?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

As oppose to MG, LEMS usually improves with

A

Exercise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Botulism?

A

-Clostridium botulinumis a bacterium that produces dangerous toxins that block nerve functions and can lead to respiratory and muscular paralysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the mechanism of action for Botulinum toxin?

A

Botulinum toxin is a specific protease that cleaves SNARE proteins present in the vesicular and presynaptic cell membranes. These SNARE proteins are involved in exocytosis, preventing the release of neurons transmitters.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the time os incubation for botulinum toxin?

A

normal: 12-36 hour

can be 6hr- 10 days

17
Q

What is the presentation of a baby with infantile botulism?

A

Classic presentation for infantile botulism includes antecedent constipation with the ascending paralysis, ptosis, dilated or unreactive pupils, and weakness in the arms and legs.

18
Q

What causes infantile botulism?

A

Spores in Honey

Types A and B- BAby

19
Q

What is wound botulism?

A
  • Spores get into an open wound and are able to reproduce in
  • Two weeks to appear.
  • Associated with injecting black tar heroin.
20
Q

What is inhalation botulism?

A
  • Does not occur naturally, it is associated with accidental or intentional (e.g. bioterrorism)
  • The median lethal is three times greater than in foodborne cases.
21
Q

What is tetanus?

A
  • Clostridium bacteria that produce tetanus toxin.
  • 7 to 21 days.
  • Inhibitory spinal interneurons. Damage to which results in disinhibition of spinal motor neurons.
  • Hyperexcitation= tetanic contractions
22
Q

What is the MOA of tetanus toxin?

A

Protease that cleaves SNARE proteins, abolition of release of inhibitory neurotransmitter from spinal interneurons.

23
Q

What is a neurotransmitter?

A

Chemical substance that is synthesized in a neuron, released at a synapse to elicit a specific response.

24
Q

What is neruomodulator?

A

Chemical messenger released by a neuron that does not directly cause EPSPs or IPSPs but instead affects the strength of synaptic transmission.

25
Q

What are the major classes of neurons transmitters?

A
  • Small molecule
  • Neuropeptides
  • Gaseous
26
Q

What the are major Small molecule Nero transmitters?

A
  • Acetylcholine
  • Excitatory: glutamate and aspartate
  • Inhibitory: GABA and Glycine
27
Q

What are the major Neuropeptides?

A
  • Opioid peptides: b-endorphin, methionine-enkephalin, leucine-enkephalin, endomorphs, nociceptin.
  • Substance P
28
Q

How are presynaptic vesicles formed?

A
  • Vesicles are synthesized in the presynaptic cell body, shuttled by fast or slow axonal transport to the nerve terminal. Filled locally produced neurotransmitter.
  • Peptide transmitters are synthesized and prepackaged in vesicles within the cell body rather than in the nerve terminal.
29
Q

Where are neurotransmitters contained?

A
  • Small-molecule transmitters: clear-core vesicles.

- Serotonin and norepinephrine are exceptions: contained in dense-core vesicles

30
Q

What is transported via slow axonal transport?

A
  • The propeptide and enzyme-filled vesicles.
  • Soluble enzymes (e.g.,acetylcholinesterase, tyrosine hydroxylase )
  • Enzymes cleave the propeptide to produce a smaller peptide transmitter that remains in the large dense-core vesicles.

31
Q

What does the SNARE protein complex include?

A

Synaptobrevin, syntaxin, and SNAP-25.

32
Q

What are the steps of release from a synaptic membrane?

A
  1. Action potential arrives and opens Ca2+ channels.
  2. Ca2+ brings to protein called synaptotagmin
  3. Activates SNARE
  4. Vesicles fuse and empty contents
33
Q

Excitatory vs Inhibitory receptors

A
  • Excitatory receptors (NMDA) cause membrane depolarization, Increased firing rates
  • Inhibitory receptors (GABA) hyperpolarize the membrane and decrease spike frequency.
34
Q

Ionotropic vs Metabotropic

A
  • Ionotropic receptors usually consist of multimeric proteins and form the pore of the ion channel (aka. ligand-gated
) SHORT DURATION
  • Metabotropic Receptors flow of ions depends on one or more metabolic steps. (Gprotein)
35
Q

How is a signal terminated?

A
  • Signal degradation: acetylcholinesterase – breaks down ACh
  • Recycle: choline taken back up, reused to make new acetylcholine
  • Diffusion

z. Neuro Class (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions