Lecture 12: Muscle - Actions & Roles Flashcards Preview

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Flashcards in Lecture 12: Muscle - Actions & Roles Deck (24):
1

Muscular + _______ systems interact to produce muscle activity

- Nervous

2

Why does the sarcoplasmic reticulum's structure have to be slightly different?

- Because there are nuclei all up and down the muscle fibre

3

What kind of messages do neurons carry?

- Electrical (action potential)

4

Tissue between neuron and muscle fibre...

- Neuromuscular Junction

5

Neuromuscular Junction features:

- Large SA
- Synaptic Cleft
- Chemicals in synaptic cleft

6

Steps occurring in action potential event....

- Electrical --> Chemical --> Electrical

7

What are t-tubules like?

- Tunnels that burrow through the muscle fibres
- Action potentials travel down t-tubules that trigger calcium release

8

Why is Ca2+ so important for contraction?

- Myosin head exposed, come up and attach to actin filament, contract, and detach

9

What is the sliding filament theory?

- Sarcomeres pulled toward each other

10

A motor unit is...

- A motor neuron, all it's little nerves, and all the muscle fibres it attaches to

11

What's controlling contraction?

- Electrical event

12

Motor unit displays _____ or ______ activation of fibres

- All or none

13

Force of contraction in a whole muscle depends on:

Characteristics of motor units:
--> Size
--> Number (increase = increase force of contraction)
--> Rate of firing'

Muscle Attachments
--> efforts needed for movement
--> determines muscle role

14

Think of bones as_____. Joint = ____. Muscle Contraction = ______. Load = _____.

- Lever
- Pivot
- Pull
- External / Internal

15

Types of levers with muscle attachments:

- 1. Stabilise Joint Position (skull + muscles @ base)
- 2. Effective at overcoming loads (ankle)
- 3. Large range of movement and speed (biceps)

16

Types of muscle action:

- Concentric
- Eccentric
- Isometric

17

What happens during concentric contraction?

- Muscle is active
- Change in joint position
- Muscle is shortening at the same time
- (Flexion)

18

What happens during isometric contraction?

- Muscle develops tension but length of muscle does not change
- eg. holding a book on hand

19

What happens during eccentric contraction?

- Muscle is active and developing tension
- Change in joint position
- Muscle lengthening
- (Extension)

20

Types of muscle role:

- Agonist
- Antagonist
- Stabiliser
- Neutraliser

21

Agonist:

- Muscle creating desired movement (bicep flexing, developing tension, and shortening) // concentric

22

Antagonist:

- Works against / with agonist, tricep + bicep
- Lengthening // eccentric

23

Stabiliser:

- Any time you're keeping still
- A muscle is active to hold a joint still

24

Neutraliser:

- Muscle eliminates an unwanted movement (possibly caused by another muscle)
- Pronator muscles neutralise supinating effect of biceps brachii