Muscle

Question 1

What are the components of thin filaments?

Answer 1

1. F-actin2. Troponin3. Tropomyosin

Question 2

Actin, troponin, and tropomyosin are components of what muscle filament?

Answer 2

Thin filament

Question 3

What constitutes thick filaments?

Answer 3

Myosin II

Question 4

What is F-actin made up of?

Answer 4

Two G-actin polymers twisted to form a double stranded helix

Question 5

Two G-actin polymers twisted to form a double stranded helix forms ___________

Answer 5

F-actin

Question 6

What are the components of troponin?

Answer 6

1. TnT2. TnC3. TnI

Question 7

What is the function of TnT?

Answer 7

Troponin subunit that binds to tropomyosin

Question 8

What is the function of TnC?

Answer 8

Troponin subunit that binds calcium

Question 9

What is the function of TnI?

Answer 9

Troponin subunit that binds troponin to actin molecule; inhibits actin-myosin interaction

Question 10

Where does the Tn complex bind to tropomyosin?

Answer 10

Grooves of actin filaments

Question 11

What constitutes a tropomyosin molecule?

Answer 11

1. Two polypeptide chains in an a-helix2. Each a-helix rests on 7 G-actin molecules, covering active site3. Head to tail of tropomyosins form tropomyosin filaments

Question 12

What does trypsin do to myosin molecules?

Answer 12

Breaks them into heavy meromyosin and light meromyosin

Question 13

What is the molecular composition of myosin?

Answer 13

2 heavy chains and 4 light chains

Question 14

What constitutes heavy meromyosin?

Answer 14

1. 4 light chains2. 2 globular chains3. Short twisted tail (a-helix)

Question 15

What constitutes light meromyosin?

Answer 15

The shafts of the heavy chains wrapped around each other

Question 16

What makes up a sarcomere?

Answer 16

Overlapping thick and thin myofilaments

Question 17

Overlapping thick and thin myofilaments make up a _______________

Answer 17

Sarcomere

Question 18

A series of sarcomeres joined end-to-end makes up a _______________

Answer 18

Myofibril

Question 19

What makes up a myofibril?

Answer 19

A series of sarcomeres joined end-to-end

Question 20

What makes up a muscle fiber (muscle cell)?

Answer 20

Many parallel myofibrils

Question 21

Many parallel myofibrils make up a ______________

Answer 21

Muscle fiber (muscle cell)

Question 22

What are the characteristics of the A band?

Answer 22

1. Dark band - thick and thin filaments2. Widest band

Question 23

What are the characteristics of the H band?

Answer 23

1. Thick filaments only2. Bisects the A band

Question 24

What are the characteristics of the I band?

Answer 24

1. Thin filaments only2. Light band3. Made up of portions of adjacent sarcomeres

Question 25

What are the characteristics of the Z disc?

Answer 25

1. Attachment for thin filaments2. Contains a-actinin3. Bisects I band

Question 26

What are the characteristics of the M line?

Answer 26

1. Consists of protein structures lying between thick and thin filaments, holding them together2. Creatine kinase is major protein3. Bisects H band

Question 27

What is the role of a-actinin?

Answer 27

Anchors thin filaments to Z disc

Question 28

What anchors thick filaments to the Z disc?

Answer 28

Titin

Question 29

What is the role of titin?

Answer 29

Anchors thick filaments to Z disc

Question 30

What is the role of myomesin and C protein?

Answer 30

Secures thick filaments at M line

Question 31

What is the role of dystrophin?

Answer 31

Cytoplasmic protein that binds actin filaments to laminin

Question 32

What makes up the sarcolemma?

Answer 32

Cell membrane + external lamina + reticular lamina

Question 33

What is endomysium?

Answer 33

Surrounds muscle fiber, consists of delicate layer of reticular fibers

Question 34

What is a fascicle?

Answer 34

Many muscle fibers bundled together

Question 35

What connective tissue surrounds a fascicle?

Answer 35

Perimysium

Question 36

What is perimysium?

Answer 36

Collagenous connective tissue that surrounds a fascicle

Question 37

What is epimysium?

Answer 37

Deep fascia, surrounds many fascicles

Question 38

What is the term for deep fascia taht surrounds many fascicles?

Answer 38

Epimysium

Question 39

What are T tubules?

Answer 39

Invaginations of sarcolemma which are continuous with extracellular space

Question 40

What is the function of T tubules?

Answer 40

Carry nerve impulses deep into cell

Question 41

What is the terminal cisterna of the sarcoplasmic reticulum?

Answer 41

Stores calcium in its lumen

Question 42

What is the triad located at the A-I junction of the sarcomere?

Answer 42

1 T tubule + 2 terminal cisternae

Question 43

What are satellite cells?

Answer 43

Regenerative cells that lie between the skeletal muscle cell and its external lamina

Question 44

New myoblasts are derived from ___________

Answer 44

Satellite cells

Question 45

What components make up the innervation of skeletal muscle?

Answer 45

1. Motor unit2. Motor end plate

Question 46

What constitutes the motor unit?

Answer 46

A lower motor neuron and all muscle fibers it innervates

Question 47

What constitutes the motor end plate?

Answer 47

1. Axon terminal2. Synaptic cleft3. Muscle cell sarcolemma

Question 48

What is myesthenia gravis?

Answer 48

Autoimmune disease causing muscle weakness

Question 49

What is the cause of myesthenia gravis?

Answer 49

Antibodies attack Ach receptors on sarcolemma of skeletal muscle, forming Ab-receptor complexes

Question 50

What is muscular dystrophy?

Answer 50

Genetic, degenerative disease affecting striated muscles

Question 51

What is the protein affected in Duchenne's muscular dystrophy?

Answer 51

Dystrophin

Question 52

Which muscle type contains a lot of glycogen?

Answer 52

Cardiac muscle

Question 53

What are some characteristics of cardiac muscle?

Answer 53

1. Weakly striated2. Short and branched cells3. Cells contain glycogen, lipid droplets, and lipofuscin4. 1-2 nuclei5. Atrial granules6. Many mitochondria7. Intercalated discs

Question 54

What are atrial granules?

Answer 54

Membrane-bound granules: 1. Contain atrial natriuretic factor and brain natriuretic factor2. Most common in right atrium

Question 55

What are intercalated discs?

Answer 55

Specialized intercellular junctions

Question 56

Are T tubules of the cardiac (ventricular) muscle larger or smaller than in skeletal muscle?

Answer 56

Larger

Question 57

What are Purkinje fibers?

Answer 57

Specialized cardiac muscle cells in the endocardium that act as batteries which relay electrical impulses to cardiac muscle fibers

Question 58

What are some characteristics of smooth muscle?

Answer 58

1. Forms sheets2. No striations3. Mononuclear - nucleus is in center4. Dense bodies - crossing of myofilament bundles5. No T tubules6. Poorly developed SR

Question 59

What are dense bodies?

Answer 59

Criss-crossing of myofilament bundles

Question 60

What is a common component of dense bodies?

Answer 60

a-actinin (similar to Z discs)

Question 61

What are caveolae?

Answer 61

Pinocytotic vesicles that form bubble like structures on inner surface of cell membrane and release calcium into cell for contraction