Lecture 5:Reflexes and muscle contraction Flashcards Preview

1st Year: Physiology and Anatomy > Lecture 5:Reflexes and muscle contraction > Flashcards

Flashcards in Lecture 5:Reflexes and muscle contraction Deck (11)
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1
Q

what cells to skeletal muscles have?

A

myocytes

2
Q

what is skeletal muscles formed from?

A

skeletal muscle fibres

3
Q

what does stimulation of muscle fibre in the skeletal muscle do?

A

excitation the entire cell

4
Q

where do motor neurones form synapses?

A

on the skeletal muscle fibres at the motor endplates

5
Q

what are slow muscle fibres?

A

postural muscles, mainly type 1 fibres

6
Q

what are fast muscle fibres?

A

mainly type 2 fibres, better suited to generate large forces but can fatigue rapidly

7
Q

how do you see the different types of fibres?

A

immunostaining

8
Q

what are isotonic contractions?

A

when muscle shortens on contraction against a constant load e.g. flexing a limb

9
Q

what are isometric contractions?

A

muscle constrained to a constant length e.g. holding heavy object still

10
Q

How does muscle fibre contraction happen ?

A
  1. Nerve AP
  2. Nerve ending secretes ACh
  3. End plate potential
  4. muscle action potential
  5. T tubules depolarise
  6. opens Ca2+ channels of sarcoplasmic reticulum
  7. sarcoplasm Ca2+ increases
  8. muscle fibre contracts
  9. Ca2+ goes back
  10. muscle fibre relaxes
11
Q

what happens in Excitation-contraction coupling?

A

AP from motor endplate, goes to T tubules, leading to SR, AP stimulates ion channels, releasing calcium, into the cytosol, myosin binds to actin( protein in thick filament). Contraction continues if Ca high and ATP present.