Muscle Tissue

Question 1

Functions of skeletal muscle

Answer 1

1. Producing movement
2. Maintaining posture and body position
3. Supporting soft tissue
4. Guarding body entrances and exits
5. Maintaining body temperature
6. Storing nutrients

Question 2

Excitability

Answer 2

The ability to receive and respond to stimulus

Question 3

Contractilicity

Answer 3

The ability of a muscle cell to shorten when stimulated

Question 4

Extensibility

Answer 4

Stretching movement of a muscle

Question 5

Elasticity

Answer 5

The ability of a muscle to recoil to its resting length

Question 6

Composition of skeletal muscle

Answer 6

Skeletal muscle tissue, connective tissue, blood vessels, and nerves

Question 7

Muscle fibre

Answer 7

Each cell in skeletal muscle tissue is a single muscle fibre

Question 8

3 layers of connective tissue surrounding muscle tissue

Answer 8

1. Epimysium: surrounds entire muscle
2. Perimysium: divides skeletal muscle into compartments
3. Endomysium: surrounds individual muscle fibres

Question 9

Fascicle

Answer 9

Bundle of muscle fibres

Question 10

Elastic connective tissue

Answer 10

1. Capillary networks
2. Myosatellite cells
3. Nerve fibres

Question 11

Myosatellite cells

Answer 11

Stem cells that help repair damaged muscle tissue

Question 12

Tendon

Answer 12

Bundle formed by collagen fibres of epimysium, perimysium and endomysium

Question 13

Aponeurosis

Answer 13

Broad sheet formed by collagen fibres of epimysium, perimysium and endomysium

Question 14

Are muscle fibres bigger or smaller than normal cells?

Answer 14

A lot bigger

Question 15

Are muscle fibres uninucleate and multinucleate?

Answer 15

Multinucleate

Question 16

Myoblasts

Answer 16

Groups of embryonic cells that fuse, forming individual multinucleate skeletal muscle fibres

Question 17

Sarcolemma

Answer 17

Plasma membrane of a muscle fibre

Question 18

Sacroplasm

Answer 18

Cytoplasm of the muscle fibre

Question 19

Transverse tubules

Answer 19

Narrow tubes whose surfaces are continuous with the sarcolemma and extend deep into the sarcoplasm

Question 20

Sarcoplasmic reticulum

Answer 20

Forms a tubular network around each myofibril

Question 21

Terminal cisternae

Answer 21

The tubules of the SR enlarge, fuse, and form expanded chambers

Question 22

Myofibril

Answer 22

Bundles of protein filaments called myofilaments

Question 23

What causes skeletal muscle fibre contraction?

Answer 23

Active shortening of myofibrils

Question 24

Composition of myofilaments

Answer 24

Thin filaments (actins)
Thick filaments (myosin)

Question 25

Sarcomeres

Answer 25

Repeating functional units of in myofibril

Question 26

Composition of thin filaments

Answer 26

F-actin, nebulin, tropomyosin, and troponin

Question 27

A bands

Answer 27

Dark bands on sacromere: thick and thin filaments

Question 28

I bands

Answer 28

Light bands on sacromeres: thin filaments only

Question 29

Sliding-filament theory

Answer 29

H and I bands narrow, zones of overlap widen and Z lines move closer together

Question 30

Excitable membranes

Answer 30

Plasma membranes that can propagate action potentials

Question 31

Neuromuscular junction

Answer 31

Synapse between neuron and skeletal muscle fibre

Question 32

Events at the neuromuscular junction

Answer 32

1. Action potential arrives triggering exocytosis of ACh into synaptic cleft 2. ACh opens membrane receptors and Na+ rush in to cell, generating action potential in sarcolemma

Question 33

Excitation-contraction coupling

Answer 33

1. Neural control 2. Excitation 3. Release of calcium ions 4. Contraction cycle begins 5. Sarcomere shortening 6. Generation of mucle tension

Question 34

Contraction cycle and cross-bridge formation

Answer 34

1. Contraction cycle 2. Active-site exposure 3. Cross-bridge formation 4. Myosin head pivoting 5. Cross-bridge detachment 6. Myosin reactivation

Question 35

Types of muscle contractions

Answer 35

Isotonic concentric: muscle tension exceeds the load and muscle shortens Isotonic eccentric: muscle tension is less than load and muscle elongates Isometric contraction: muscle as a whole does not change length

Question 36

Anaerobic process

Answer 36

Glycolysis

Question 37

Aerobic metabolism

Answer 37

Requires oxygen

Question 38

Types of skeletal muscle fibres

Answer 38

1. Fast fibers 2. Slow fibers - myoglobin 3. Intermediate fibers

Question 39

Skeletal muscle tissue

Answer 39

Striated, many peripherally located nuclei - voluntary

Question 40

Cardiac muscle cells

Answer 40

- Striated - 1 nucleus - Aerobic metabolism - Intercalated discs bind sarcolemmas of neighbouring cardiac muscle cells

Question 41

Smooth muscle tissue

Answer 41

- Non-striated involuntary muscle tissue - No sarcomeres - Involuntary