Lecture 11: Muscle - Structure & Function Flashcards Preview

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Flashcards in Lecture 11: Muscle - Structure & Function Deck (22):
1

What’re the three different types of muscle?

- Skeletal, Smooth, and Cardiac

2

What are the functions of skeletal muscle?

- Movement
- Heat production
- Posture (maintaining posture for long periods of time)
- Communication (diaphragm needs to contract in a certain way to make sounds)

3

What happens when we want to conserve heat?

- We shiver

4

What does myo / sarco mean?

- Muscle (in Latin & Greek)

5

Transverse leg picture includes:

- Fascia, Fat, Skin, Blood Vessels, Nerves, Muscles

6

How is connective tissue arranged?

- Epimysium → Fascicle → Covered in perimysium → Muscle Fibre → Wrapped by endomysium

7

How is muscle tissue arranged?

- Muscle Fibre → Sarcoplasmic Reticulum → T Tubule → Myofibrils → Myofilaments (in sarcomere)

8

How big is a skeletal muscle fibre?

- Up to 40cm, parallel, cylindrical, multi-nuclear

9

What does a skeletal muscle fibre look like?

- Striated, protein arrangement

10

Myofilaments are made of…

- Thick and thin proteins

11

The thin filaments attached to the sarcomere are made up of…

- Mostly Actin (Some Troponin, and Tropomyosin)

12

The thick filaments are made up of…

- Myosin heads

13

What is the sarcolemma?

- Phospholipid bilayer (membrane)

14

What triggers muscle contraction?

- Calcium

15

What is a sarcomere?

- A contractile unit
- End-on-end along myofibril length

16

How big is a sarcomere?

- 2 micrometers

17

How does a muscle actually contract?

- Thin draws towards each other over thick
- Z lines move closer together
- Individual lengths stay the same
- Energy is consumed
- Calcium is essential

18

If you want a large ROM do you want long or short muscle cells?

- Long
- Means it can shorten more

19

What determines thickness of muscle?

- Number of muscle fibres
- Greater number of fibres = greater CSA
- And tension

20

Why is the angled arrangement of muscle fibres important?

- More tension is developed
- Because there are more fibres in a smaller space
- Not so great ROM

21

Are relaxed muscles active?

- Slightly

22

How’re we maintaining posture?

- Nerve impulses go down from spinal chord and activate muscle fibres
- No movement produced but keeps muscles firm and healthy
- Helps stabilize joints and maintain posture