Brainscape's Knowledge GenomeTM

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


See full index

Year 2 Collin > Neuro 9 - Neuromuscular Junctions and SC > Flashcards

Neuro 9 - Neuromuscular Junctions and SC Flashcards

1
Q

What are the 2 directions that a membrane potential can be altered to?

A
  1. EPSP - excitatory - membrane potential brought closer to threshold (i.e. less negative)
  2. IPSP - inhibitory - membrane potential brought further away from membrane potential (i.e. more negative)

PSP = post synaptic potential

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

What neurotransmitter is used at the NMJ?

A

ACh

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

Explain how an AP is brought about in a muscle fibre

A
  1. AP arrives at NMJ
  2. Ca influx causes ACh release
  3. ACh binds to receptors on motor end plate
  4. Ion channel opens - Na influx causes AP in muscle fibre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of motor neurone is connected to the motor end plate?

A

Alpha motor neurone (aka lower motor neurone)

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

What do alpha motor neurones innervate?

A

Extrafusal muscle fibres of SkM

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

What is meant by motor neurone pool?

A

All of the alpha motor neurones innervating a single muscle

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

Never eat shredded wheat, what is the alpha motor neurone configuration in the butterfly section of the vertebrae?

A

Flexors

Proximal Distal

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

What is a motor unit?

A

A neuron and all of the muscle fibres innervated by that neurone

Smallest functional unit to produce force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the types of motor unit?

A
  1. Slow (S, Type 1)
  2. Fast, fatigue resistant (FR, Type 2A)
  3. Fast, fatiguable (FF, Type 2B)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 2 regulatory mechanisms of force production by a muscle

A
  1. Recruitment - governed by “size principle”. Small units recruited first (usually slow twitch). More force required = more units recruited.

Recruitment allows fine control when low forces are required.

  1. Rate coding - Firing rate increases to accommodate for larger force production. Summation = when units fire too quickly to allow muscle to relax between APs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do neurotrophic factors do?

A

Prevent neuronal death, promote growth of neurons after injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the most common conversion of muscle fibre type?

A

Type 2B to 2A after training

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

If severe reconditioning (e.g. spaceflight) or spinal cord injury occurs, what muscle fibre type change can occur?

A

Type 1 to type 2

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

Ageing can result in loss of type 1 and type 2 muscle fibres, but which type is lost preferentially?

A

Type 2

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

Pyramidal tracts are crossed for limbs and uncrossed for?

A

Trunk muscles

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

What is the Hoffman reflex?

A

Means of stimulating a nerve without using physical stretch of a tendon.

M-wave = initial direct contraction of the motor neurone that has been stimulated

Short while after, H-wave = AP in sensory neurone that has been stimulated excites a motor neurone

17
Q

Flexion withdrawal reflexes ensure that other muscles maintain correct posture (Eg)

A

T

18
Q

Supraspinal centres (higher CNS) centres exert inhibitory and excitatory regulation on stretch reflexes. Inhibitory control dominates usually.

A

T

19
Q

In reflexes, there is usually an inhibitory signal to the antagonist as well as a excitatory signal to the agonist (i.e. quadriceps excited, hamstrings inhibited)

A

T

20
Q

Which neurones are more amenable to electrical impulses?

A

Sensory neurones. Which is why, in Hoffmans reflex, easier to get a response from a H wave than a M wave

21
Q

What are the 2 polysynaptic reflexes called?

A

Flexion withdrawal and crossed extensor

22
Q

What does removing descending inhibitory control do?

A

Causes brisk reflexes and spasticity in muscles

23
Q

What do strokes lead to?

A

Loss of descending inhibition of reflexes - causes HYPER-REFLEXIA

24
Q

What is a clonus?

A

Repeated, rhythmic muscular spasmic contractions

25
Q

What is babinskis sign?

A

Stroking the bottom of their foot causes plantar extension -

26
Q

How is hypo-reflexia often caused?

A

By lower motor neurone lesions

27
Q

Give an example of a monosynaptic reflex

A

Stretch

Year 2 Collin (114 decks)

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