Module 102 - The Body's muscle: Skeletal, cardiac and smooth Flashcards Preview

Year 1 - Module 102 > Module 102 - The Body's muscle: Skeletal, cardiac and smooth > Flashcards

Flashcards in Module 102 - The Body's muscle: Skeletal, cardiac and smooth Deck (31):
1

Examples of where smooth muscle is found

Gut, viscera

2

Examples of where skeletal muscle is found

Gross muscles, locomotor

3

Examples of where cardiac muscle is found

Heart beating

4

Which muscles are considered to be striated

Cardiac and skeletal

5

Order of muscle arrangement

Muscle fibre --> myofibrils --> myofilaments

6

Describe microstructure of skeletal muscle

- Elongated multinucleated cells
- Peripheral nuclei
- Grouped into boundles called fasicicles
Surrounded by connective tissue

7

Layers of skeletal muscle

- Epimysium surrounds entire muscle
- Perimysium surrounds fascicles
- Endomysium surrounds each fiber

8

Which layer is the basement membrane continuous with?

Endomysium

9

What is the sarcolemma

The muscle fiber's cell membrane

10

What is the sarcoplasm

The fiber's cytoplasm

11

What is the purpose of satellite cells

Allow skeletal muscle to regenerate

12

What are the two main types of myofilaments

- Actin(thin)
- Myosin(Thick)

13

How is muscle contraction controlled

- Acetylcholine passes the nerve impulse across the gaps from the motor end plate to the muscle fiber(neuromuscular junction)

- Impulse spreads into the sarcolemma and into T tubules

- Sarcoplasmic reticulum is a smooth endoplasmic reticulum in muscle whose function is to store and release Ca when needed

14

What does the sarcolemma allow for?

Simulataneous contraction

15

What are the types of muscle fibre arrangements?

- Flat(parallel)
- Pennate
- Fusiform
- Quadrate
- Circular
- Multiheaded(bellied)

16

Describe flat muscles

- Parallel fibres within an aponeurosis
- Eg external oblique

17

Describe pennate muscles

- Feather like may be unipennate, bipennate or multipennate eg flexor digitorium

18

Describe fusiform muscles

- Spindle shaped with round bellie and tappered at tendons

19

Describe quadrate muscles

- Four sides eg pronator quadratus

20

Examples of circular muscles

- Orricucle, obicularis oris

21

Examples of multiheaded muscles

Biceps, digastric

22

What is the force generation and movement velocity of muscles dependent on?

- Muscle size
- Origin/insertion
- Fiber arrangement
- Fiber length

23

Muscle regeneration in the three types of muscles

Skeletal muscle - satellite cells

Cardiac muscle - incapable(fibrosis)

Smooth muscle - limited(cell division)

24

Function of cardiac muscle

- Continuous rhythmic contractions to pump blood from the heart

25

What regulates the intrinsic contractions

- Autonomic nervous system
- Sympathetic increases heart rate
- Parasympathetic decreases heart rate(via vagus)

26

Describe microstructure of cardiac muscle

- Central nuclei
- Branching pattern
- Cells connected by intercalated discs
- Myofibrils less defined
- No defined connective tissue layer

27

What do intercalated discs contain

1. Fascia adhesions - Desmosomes allow coordination of contraction

2. Gap junctions - Allow fast conduction and dissemination of action potentials(supports synchronised contraction of the heart)

28

What is the function of smooth muscle?

- Slow sustained contractions to move contents through viscera
- Low force, contractions may be rhythmic or wave like

29

Describe the microstructure of smooth muscle

- Spindle shaped
- Single central nuclei
- Branching pattern
- Contractile proteins not arranged as myofibrils/sarcomeres
- Proteins criss-cross and anchor to focal densities
- Cells run parallel to force of contraction
- Has a supporting network of connective tissue

30

What are muscular dystrophies?

- Group of genetic diseases causing progressive muscle weakness

31

What are cardiomyopathies

- Deterioration in heart muscle function