Muscle

Question 1

3 types of muscle

Answer 1

Cardiac, smooth, skeletal

Question 2

Voluntary muscle

Answer 2

Skeletal

Question 3

Involuntary muscle

Answer 3

Cardiac, smooth

Question 4

what are myofilaments made of?

Answer 4

actin, myosin

Question 5

What is the epimysium

Answer 5

Connective tissue that surrounds the entire muscle

Question 6

What is the perimysium

Answer 6

Connective tissue that surrounds the fasicle

Question 7

What is the endomysium

Answer 7

Connective tissue that surrounds each muscle fiber (muscle cell)

Question 8

What is a synctium?

Answer 8

A multinucleated cell that was created through the fusion of unicellular cells

Question 9

Characteristics of skeletal muscle

Answer 9

Each cell has multiple, peripherally located nuclei

Striated

Question 10

How vascularized is skeletal muscle?

Answer 10

Extensive capillary network due to high energy requirement

Question 11

What is a sarcomere?

Answer 11

Single contraction unit (Z dsk to Z disk)

Question 12

What are thin filaments of the sarcomere

Answer 12

Actin

Question 13

What are thick filaments of the sarcomere

Answer 13

Myosin

Question 14

What filament is most abundant in I band?

Answer 14

Actin, troponin, tropomyosin

Question 15

What filament is most abunant in A band?

Answer 15

Myosin and Actin

Question 16

What is the M line?

Answer 16

Where no actin filaments connect with myosin and two myosin filaments cross connect

Question 17

Where are troponin and tropomyosin located?

Answer 17

I band

Question 18

What filament is in the H band?

Answer 18

Myosin only

Question 19

Which bands shorten during contraction?

Answer 19

I and H bands

Question 20

How is troponin and tropomyosin configured?

Answer 20

Tropomyosin is wrapped around actin covering myosin binding sites

Troponin is attached to tropomyosin

Question 21

Is troponin present in smooth muscle?

Answer 21

No

Question 22

What is troponin C

Answer 22

Troponin C binds the calcium to activate movement of tropomyosin

Question 23

How are myosin filaments arranged?

Answer 23

Two heavy chain tails are connected together with cross bridge heads

These heads move back during contraction

Question 24

What 2 structures are important for calcium and muscle contraction?

Answer 24

Sarcoplasmic reticulum and T-tubules

Question 25

What does the sarcoplasmic reticulum do?

Answer 25

Calcium storage

Question 26

What do transverse tubules do?

Answer 26

Cell membrane invaginations that extend between the myofibrils and ensure high calcium inside every cell

Question 27

What are terminal cisternae?

Answer 27

Expansions of sarcoplasmic reticulum Located adjacent to T-tubules

Question 28

What is a triad?

Answer 28

One T-tubule and its adjacent terminal cisternae

Question 29

What happens at the neuromuscular junction?

Answer 29

ACh causes depolarization which spreads via T-tubules to triad junction to the dihydropyridine receptor activates the ryanodine receptor on the SR

Question 30

What action does myosin have on ATP?

Answer 30

Hydrolyzes ATP

Question 31

What are red muscle fibers?

Answer 31

Aerobic, endurance Lots of mitochondria High myoglobin Slow twitch, sustained contraction

Question 32

What are white muscle fibers

Answer 32

Sprint, anaerobic | Fast twitch

Question 33

What are intermediate fibers?

Answer 33

Hybrid, mostly fast twitch

Question 34

Where are muscle spindles located

Answer 34

Between endomysium and perimysium

Question 35

What do muscle spindles do?

Answer 35

Determine position of body parts and extent of contraction

Question 36

Characteristics of cardiac muscle

Answer 36

Striated Involuntary One centrally located nucleus Intercalated discs

Question 37

What is an intercalated disc?

Answer 37

Electron dense junctional complex with gap junctions, desmosomes, fascia adherens

Question 38

What allows simultaneous contraction in cardiac muscle?

Answer 38

Intercellular junctions, anchors, sarcomeres

Question 39

What is fascia adherens

Answer 39

Similar to Zonula Adherens but not the same (FA not belt-like)

Question 40

How are contraction signals conducted in the heart?

Answer 40

Purkinje fibers and gap junctions

Question 41

What are purkinje fibers?

Answer 41

Modified cardiac myocytes, assist in cardiac contraction

Question 42

Characteristics of smooth muscle

Answer 42

``` Non-striated Involuntary Spindle-shaped cells One elongated nucleus Disorganized myofilaments ```

Question 43

Does smooth muscle have connective tissue?

Answer 43

Yes, but there is little CT separating muscle cells (endomysium)

Question 44

How does smooth muscle contract?

Answer 44

Myosin must be phosphorylated in order to bind to actin Ca binds to calmodulin which activates light chain kinase

Question 45

How is light chain kinase reglated?

Answer 45

Calmodulin Ca complex An increase in cytosolic Ca induces calmodulin binding to myosin light chain kinase

Question 46

How is skeletal muscle regenerated?

Answer 46

Satellite cells

Question 47

Characteristics of satellite cells

Answer 47

Spindle-shaped cells with little cytoplasm Located under the external lamina of muscle cell Forms myoblasts which differentiate in to muscle fibers

Question 48

What can inhibit muscle cell regeneration?

Answer 48

Damage to external lamina

Question 49

How is muscle repar generally achieved?

Answer 49

Formation of connective scar tissue

Question 50

What is the external lamina?

Answer 50

Surrounds sarcolemma of muscle cells Secreted by muscle cells

Question 51

Is there cell regeneration in cardiac muscle?

Answer 51

Very little | Transplantation of stem cells can initiate regeneration

Question 52

How does smooth muscle regenerate?

Answer 52

Normal cell division

Question 53

What is the pathological result of a cardiac infarction?

Answer 53

Muscle is replaced with connective scar tissue, not muscle so it loses contractability