Lecture 3 - Neuromuscular 1

Question 1

major divisions of the nervous system

Answer 1

Question 2

structures of the Neuron

Answer 2

Question 3

describe resting membrane potential

Answer 3

• > -70mV
• > inside more negative than outside
• > Na channels are closed (want to enter but cant’t)
• > K channels are open

Question 4

Depolarization vs Hyperpolarization

Answer 4

Depolarization
- > occurs when inside of cell becomes less negative (-70 to 0mV)
- > Na channels open
- > requires an impulse to arise and travel
Hyperpolarization
- > occurs when inside of cell becomes more negative after the impulse than initial readings (-70 to -90)
- > makes it difficult for another impulse to occur

Question 5

graded potentials vs action potential

Answer 5

GP
- > will decide if signal will be passed along to the axon
- > can excite or inhibit a neuron
AP
- > GPs that pass the potential threshold triggering an AP that goes down the neuron and to the next cell
- > only excitatory
- > lasts around 1ms

Question 6

inhibitory vs excitatory signals

Answer 6

inhibitory
- > K efflux (hyperpolarization)
excitatory
- > Na influx (depolarization)

Question 7

all or none principle

Answer 7

an AP happens or it doesn’t, can’t have half and AP

Question 8

threshold values

Answer 8

Question 9

Na-K pump

Answer 9

Question 10

absolute vs relative refractory periods

Answer 10

Absolute refractory period
- > during depol.
- > neuron unable to respond to another stimulus
- > Na channels already open, nothing else can come in
Relative refractory period
- > during repol.
- > neurons only respond to very strong stimulus
- > K channels open (Na closed but could open again)

Question 11

how does the diameter of an axon influence the speed of an impulse

Answer 11

larger the diameter the faster the impulse

Question 12

Myelin

Answer 12

speeds up propagation

• > fatty sheath around axon
• > non continuous

Question 13

multiple sclerosis

Answer 13

degredation of myelin

Question 14

synapse

Answer 14

gap/junction between neurons

- > AP must jump across

Question 15

path of an impulse

Answer 15

Question 16

neurotransmitters

Answer 16

chemicall messengers that carry electrical AP across synaptic cleft and mind to receptors on postsynaptic surfaces
- > stimulate GPs in postsynaptic neurons

Question 17

neuron-muscle communication

Answer 17

neuromuscular junction
uses acetylcholine (ACh) as a neurotransmitter that excites the axon
- > ACh bind to receptor at motor end plate (specifically plasmalemma) and cause depolarization

Question 18

categories of neurotransmitters

Answer 18

1. Small molecules, rapid acting

2. neuropeptides, larger and slow acting

Question 19

which neurotransmitters govern exercise

Answer 19

ACh and Norepinephrine (NE)

- > ACh stimulates skeletal muscle contractions and NE mediates sympathetic NS effects

Question 20

PPARGC1gamma

Answer 20

peroxisome proliferator-activated receptor-gamma coactivator

• > released during exercise
• > increases the number vesicles
• > increases the number of receptors on cell, which increases the effect of ACh
• > exercise leads to inc. sensitivity to ACh

Question 21

neuromuscular effects of HIIT vs END training

Answer 21

• > both have a similar improvement to VO2max
  HIIT: increase in force production, motor unit firing, motor unit discharge rate
  END: no changes