Muscle

Question 1

Force is produced by movement from?

Answer 1

Actin fibres over myosin fibres

Question 2

What are the 4 types of contractile cells?

Answer 2

Muscle cells, myoepithelial cells, myofibroblasts and pericytes

Question 3

What are the types of muscle cells?

Answer 3

Skeletal/voluntary, cardiac, smooth/involuntary

Question 4

What are the three non-muscle contractile cells?

Answer 4

Myoepithelial cells, myofibroblasts and pericytes

Question 5

What are myoepithelial cells?

Answer 5

They are flattened cells and have contractile protein arrangement similar to smooth muscle

Question 6

Myofibroblasts have characteristic of both?

Answer 6

Fibroblasts and smooth muscle

Question 7

What are myofibroblasts?

Answer 7

They enlarge and proliferate artery injury and secrete collage to provide a scaffold for repair

Question 8

What are pericytes?

Answer 8

Inconspicuous cells found around capillaries and venules

Question 9

What can pericytes act like?

Answer 9

Stem cells

Question 10

What can pericytes control?

Answer 10

Control capillary diameter

Question 11

How are multinucleate myotubes formed?

Answer 11

Within the mesenchyme, cells will align and eventually lose their separating cell membranes

Question 12

What are the names given to skeletal muscle?

Answer 12

Skeletal, voluntary and striated

Question 13

What percentage does skeletal muscle have in the body weight?

Answer 13

40%

Question 14

How is muscle tissue formed?

Answer 14

From muscle cells and associated connective tissue

Question 15

What do muscles contain?

Answer 15

Blood vessels, nerves, lymphatics, connective tissue and specialised sense organs

Question 16

Skeletal muscle fibres are?

Answer 16

Strained, unbranded and multinucleate

Question 17

Where is the nuclei in skeletal muscle?

Answer 17

At the periphery of the fibre, just under the cell membrane (sarcolemma)

Question 18

Muscle fibres are grouped into bundles called?

Answer 18

Fasicles

Question 19

The connective tissue that surrounds the muscle as a whole is called?

Answer 19

Epimysium

Question 20

The connective tissue around a single fasicle is called?

Answer 20

Perimysium

Question 21

The connective tissue around a single muscle fibre is called?

Answer 21

The endomysium

Question 22

Fasicles contain?

Answer 22

Many muscle fibres

Question 23

Muscle fibres contain?

Answer 23

Many myofibrils

Question 24

Myofibrils contain?

Answer 24

Many sarcomeres

Question 25

What are sarcomeres?

Answer 25

Unit of contraction of the muscle cell

Question 26

Sarcomeres are the...

Answer 26

Smallest contractile elements in the striated muscle cell

Question 27

The sarcomeres extends from?

Answer 27

One z line to the next

Question 28

What is the motor unit?

Answer 28

The motor neurone and all of the muscle fibres that it innervates.

Question 29

The fewer number of muscle fibres in a motor unit...

Answer 29

The finer the control of movement

Question 30

Fibres in a motor unit are?

Answer 30

Scattered in the muscle

Question 31

The motor neuron is in the?

Answer 31

Motor end plate

Question 32

What are the classes of muscle fibres in a motor unit?

Answer 32

Type I, IIA, IIB

Question 33

What junction does muscle fibres have?

Answer 33

Neuromuscular junction

Question 34

What happens in a neuromuscular junction?

Answer 34

Motor axons terminate at a motor end plate and action potentials arriving in the axon cause release of acetylecholine and initiate an action potential in the sarcolemma

Question 35

What network of tubules extend from the sarcolemma into the cell?

Answer 35

T - tubules

Question 36

T tubules open to what side of the cell membrane?

Answer 36

The outside

Question 37

The sarcoplasmic reticulum contains?

Answer 37

A high concentration of Ca and small branches of it lie on either side of the t tubules

Question 38

What is the triad?

Answer 38

Each segment of the t tubules associated with the sarcomere is flanked by segments of the sarcoplasmic reticulum.

Question 39

When an action potential arrives at the neuromuscular junction, what is released?

Answer 39

Acetylcholine

Question 40

What is type I muscle fibre?

Answer 40

Relatively slow contracting fibres that depend on oxidative metabolism. Abundant mitochondria and myoglobin Resistant to fatigue Called red fibres and are aerobic

Question 41

What is type IIA muscle fibre?

Answer 41

Uncommon Fast twitch but fatigue resistant

Question 42

What is type IIB muscle fibre?

Answer 42

Fast contracting fibres that depend on anaerobic metabolism. Fewer mitochondria and less myoglobin than type I fibres Fatigue easily and produce greater force Called white fibres

Question 43

Muscle are attached to bone by?

Answer 43

A tendon of dense regular connective tissue

Question 44

The collagen of the tendon that attaches to ends of muscle fibres occurs at what junction?

Answer 44

Myotendinous junction

Question 45

Tendons have poor blood supply therefore are slow at?

Answer 45

Healing when damaged

Question 46

Muscle spindles contain what kind of fibres?

Answer 46

Intrafusal fibres

Question 47

What are extrafusal muscle fibres?

Answer 47

Normal contractile muscle fibres that make up the large majority of a muscle

Question 48

Cardiac muscle forms?

Answer 48

Major parts of the walls of the heart chambers and origins of the great vessels

Question 49

Cardiac muscle has?

Answer 49

Striations

Question 50

Where is the single nucleus of cardiac muscle found?

Answer 50

Near the centre of the fibre

Question 51

What are the dark irregular lines in cardiac muscle?

Answer 51

Intercalated discs

Question 52

What are intercalated discs?

Answer 52

Sites of end to end attachments between adjacent cells

Question 53

Intercalated discs contain?

Answer 53

Multiple intercellular junctions to maintain mechanical integrity

Question 54

Skeletal muscle forms a population of myoblasts called?

Answer 54

Satellite cells

Question 55

What are the satellite cells?

Answer 55

They are pressed against the outer surface of the sarcolemma of the muscle cell, under the surrounding basal lamina

Question 56

What happens when satellite cells become damaged?

Answer 56

They become activated and proliferate to form new muscle fibres

Question 57

Smooth muscle is...

Answer 57

Involuntary

Question 58

Smooth muscle had no

Answer 58

Striations

Question 59

Why is smooth muscle involuntary?

Answer 59

Because it is not under conscious control and visceral because it is predominantly found in organs

Question 60

Fibres or smooth muscle are?

Answer 60

Elongated and spindle shaped

Question 61

Fibres of skeletal muscle are?

Answer 61

Long cylinders

Question 62

The cigar shaped nucleus of smooth muscle is located?

Answer 62

Near the centre of each fibre

Question 63

Smooth muscle cells contain?

Answer 63

Actin and myosin filaments that allow contraction

Question 64

In smooth muscle, the actin and myosin are not?

Answer 64

As well organised as they are in skeletal and cardiac muscle

Question 65

Where is smooth muscle found?

Answer 65

In the walls of tubes

Question 66

Examples of where smooth muscle is found?

Answer 66

Gut, respiratory tract, blood vessels and the uterus. Also the iris of the eye

Question 67

Smooth muscle receives signals for?

Answer 67

Both contraction and relaxation

Question 68

Smooth muscle contracts either?

Answer 68

Continuously or rhythmically in the absence of stimuli

Question 69

Where can stimuli arrive from?

Answer 69

Autonomic nervous system