Muscles- Striated and Smooth Flashcards Preview

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Flashcards in Muscles- Striated and Smooth Deck (39):
1

Where are striated muscles present

In skeletal muscle and in the heart (cardiac) muscle

2

What type of muscle is this

Striated muscle

3

What are the three main parts of skeletal muscle

1. Epimysium 2. Perimysium 3. Endomysium

4

What holds the muscle together

Connective tissue

5

What are the 3 connective tissue elements of skeletal muscle main from

Collagen and fibroblasts

6

What does connective tissue provide

A route for blood vessels and nerves to get to teh muscle fibre

7

What is a sarcomere

The basic structural unit for muscle contraction

8

What are the two types of filaments in a muscle

Thick myosin and thin actin

9

What leads to overall shortening (contraction) of a muscle

Shortening of individual fibres. Actin filaments are pulled closer together meaning sarcomeres shorten myofibrils and whole muscle shortens.

10

What are the subcellular organelles involved in muscle contraction

1. Sarcolemma 2. Mitochondria 3. Myofibrils 4. Tubules of sarcoplasmic reticulum. 5. T tubule

11

What is the basis for shortening or muscle fibres

Sliding between muscle filaments is the basis for shortening muscle fibres

12

Outline the events that lead to contraction in striated muscle

  1. Muscle cell is excited (depolarised) by nerve action potential.
  2. Depolarisation carried into the depths of the cell by T-tubules.
  3. Ca2+ is released from the sarcoplasmic reticulum.
  4. Ca2+ binds to troponin, releasing its hold on actin filaments.
  5. Tropomyosin molecules can now change position
  6. Myosin can now bind to actin by cross bridges.
  7. Actin filaments move closer together = contraction.

13

What are the 3 different types of skeltal muscle fibres

Type 1 Type 2A Type 2B

14

Describe type 1 fibres

(slow-oxidative)- 'slow twitch', fatigue-resistant

15

Describe type 2A muscle fibres

(fast-oxidative)- 'fast twitch', less fatigue resistant than type 1

16

Describe type 2B muscle finres

(fast-glycolytic)- 'fast twitch', fatigue easily

17

Which type of muscle fibres are the postural muscles of the neck, back and legs rich in

Type 1 fibres

18

Which type of muscle fibres are the muscles of the shoulders and arms rich in

Type 2B (short periods of time, large amount of tension)

19

Which type of muscles fibres are the legs rich in

Type 1 and Type 2B (walking and running)

20

How do cardiac muscle fibres differ from striated muscle fibres (5 things) Neil Buys Irregular Apples Greviously

  1. Nucleus is quite central in cardiac
  2. Cardiac muscle fibres branch
  3. Cardiac muscle fibres have transverse structures called intercalated discs which join neighbouring muscles
  4. Cardiac muscle fibres are instigated by the ANS
  5. Individual cardiac muscle cells are connected by gap junctions

21

What is the purpose of intercalated discs in cardiac muscle fibres

To join muscle fibres together for strength

22

What is the function of gap junctions

They allow depolarisation of one cell to pass to another

23

What organelle is abundant in both types of striated muscle fibres and why

Mitochondria to provide energy as contraction requires a lot of energy

24

Where does smooth (non-striated) muscle occur (5 things Hairy Baboons Itch Nasty Scrotum)

1. Walls of hollow organs. 2. Walls of blood vessels. 3. Iris of the eye 4. Nipples 5. Skin- attached to hair follicules.

25

There are sarcomeres in non-striated muscles- True/False

False, there are no sarcomeres

26

Describe smooth muscle cells

Long thin cells with long thin nuclei which are 1mm long and 8 um wide

27

How long are smooth muscle cells

20um-1mm

28

What is the diameter of smooth muscle cells

5-8um

29

What type of cells are these

Smooth muscle cells

30

What does the contraction of smooth muscle cells look like

Nucleus curls and cell shrinks to 30% of its resting length

31

What is this cell feature

A nuclear pole region of a smooth muscle cell

32

What organelles are smooth muscle cells rich in

Rough endoplasmic reticulum, mitochondria, golgi apparatus

33

What type of cell is this and label its features

Dense bodies (contain alpha-actin). Sarcoplasmic reticulum Ca2+ storage.

34

What is the purpose of intermediate filaments in smooth muscle cells

They provide extra support

35

Describe contraction in smooth muscle cells

Contraction

36

How are smooth muscle cells organised in blood vessels

Circular or spiral

37

How are smooth muscle cells organised in the intestine/ bladder

Layered

38

How are smooth muscle cells organised in the uterus

Reticular (allows to expand during pregnancy)

39

Why is the smooth muscle cell's relationship with the ECM important

It enables the smooth muscle cell to change in size