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Flashcards in Exam 1 Deck (98)
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1
Q

What does Titin connect the myosin filament to?

A

The z-disk

2
Q

What is Titin connected to?

A

The z-disk and the I band

3
Q

What type of stabilizer is Titin?

A

Longitudinal

4
Q

What is a possible property of Titin?

A

Elastic ability

5
Q

What is hyperplasia?

A

An increase in muscle fibers

6
Q

What is hypertrophy?

A

An increase in myofibrils within a muscle fiber

7
Q

What makes up the I-band?

A

Actin which is supported by nebulin and insertion to z-disks

8
Q

What are the proteins that form intermediate filaments? What do these make up? Are these contractile?

A

desmin, vimentin and synemin
The Z-disk
No these are not contractile

9
Q

What purpose do desmin, vimentin and synemin serve?

A

They attach the z-disk to the cytoskeleton and keep myofibrils “in register” within the muscle fiber.

10
Q

Are the actin attachments staggered or straight on either side of the z-disk?

A

Yes

11
Q

What is the order of the following from inside out: fasicle/muscle fiber/sarcomere/muscle/myofibril

A

sarcomere- myofibril- muscle fiber- fasicle(grouping of fibers)- muscle

12
Q

How many nuclei per myofibril?

A

Many! They are multinucleated

13
Q

Where are the nuclei located in muscle cells? What structure do they trend towards?

A

Dispersed along inner surface(periphery) of the plasmalemma. Trend towards motor end-plate region.

14
Q

What organelle the endoplasmic reticulum associated with?

A

The nuclei

15
Q

What is the function of the endoplasmic reticulum?

A

Transportation and modification of cellular proteins outside of the cell

16
Q

What coordinates protein synthesis and is involved with the ER?

A

Ribosomes

17
Q

Analogy) Protein synthesis: Amino Acids

A

Words: Letters

18
Q

What do mitochondria create?

A

Adenosine Tri-Phosphate (ATP)

19
Q

What substrates are associated with mitochondria?

A

Various enzymes, NADH, FADH2, Electron Transport Chain

20
Q

What type of metabolism is the mitochondria associated with?

A

Aerobic

21
Q

Where are mitochondria typically located?

A

Between myofibrils in Z-line region and in relation to nuclei and motor end-plate

22
Q

The mitochondria form a network, what is this called?

A

Mitochondrial reticulum

23
Q

The inner membrane of mitochondria are folded, forming ___.

A

Cristae

24
Q

Between mitochondrial Cristae, there is a matrix which houses ___

A

Krebs cycle enzymes and mitochondrial DNA(mtDNA)

25
Q

Can mitochondrial networks split and fuse?

A

Yes

26
Q

What locations can mitochondria be located?

A

Subsarcolemmal and Intermyofibrillar

27
Q

Subsarcolemmal mitochondria are positioned to receive what?

A

O2 from nearby arteries

28
Q

What function do subsarcolemmal mitochondria provide in regards to integrity?

A

Believed to provide energy required to maintain sarcolemmal integrity(ion and metabolite exchange)

29
Q

Where are a significant portion of the mitochondria located?

A

Subsarcolemmal

30
Q

What mitochondria are located within the contractile elements?

A

Intermyofibrillar

31
Q

Which mitochondria have higher activity per unit mass?

A

Intermyofibrillar

32
Q

What role do intermyofibrillar mitochondria have?

A

Maintaining ATP supply for energy transduction during contraction

33
Q

What type of metabolism are the cytoplasmic components associated with?

A

anaerobic

34
Q

What makes up the cytoplasmic components?

A

soluble proteins
cytoskeletal components
glycogen granules
glycolytic enzymes

35
Q

What primary proteins make up the filamentous components?

A

myosin and actin

36
Q

What action do myofibrils perform?

A

Contract and relax

37
Q

What structures/organelles are intertwined with the myofibrils?

A

mitochondria, SR and T-tubule system

38
Q

What are the two primary protein filaments?

A

Actin and myosin

39
Q

The protein filaments connect to the endomysial connective tissue which connects to the tendon with these attachment proteins:

A

vinculin, talin, paxillin and tensin

40
Q

The A band is located ___ and consists of ____?

A

at the center of the sarcomere

myosin

41
Q

The I band is located ___ and consists of ___?

A

from Z-disk to A-band

contains Actin

42
Q

In the resting sarcomere, do actin and myosin overlap?

A

Yes

43
Q

The H zone is located ___ and consists of ___?

A

the center of the A band

only, myosoin(no overlap)

44
Q

The M region is located ___ and consists of ___?

A

the very center of the sarcomere

filaments cross connecting myosin

45
Q

Where is alpha actinin located?

A

The z disk, providing support and connecting actin proteins to z disk

46
Q

List the myofilaments:

A

Troponin(I, C and T), Tropomyosin and Nebulin

47
Q

What size protein is Nebulin? What function does it serve?

A

It is large

It holds Actin in place

48
Q

What is the largest protein in the body?

A

Titin

49
Q

What function do the intermediate fibers serve for the z-disk.

A

They (desmin, vimentin and synemin) attach the Z-disk to the cytoskeleton

50
Q

What membrane components are there in skeletal muscle?

A

SR and T-Tubules

51
Q

What is the main function of the SR?

A

Release and store Ca++

52
Q

Where does the SR release Ca++ into?

A

cytosol

53
Q

Where does the Ca++ primarily bind to once in the cytosol?

A

TnC on troponin complex

54
Q

What SR membrane components are responsible for release/uptake of Ca++?

A

The Ryanodine receptors release Ca++ into cytosol

The SERCA pump sequesters Ca++

55
Q

Where do the T-tubules exist in skeletal muscle?

A

They lie perpendicular to muscle fiber long axis and extend into the myofilaments at junctions of A and I bands

56
Q

What are terminal cisternae?

A

These are the lateral sacs of the SR near the T-tubules

57
Q

What makes up the triad?

A

TC of SR/T/TC of SR

58
Q

What purpose do the T tubules serve?

A

A place for ion exchange between extracellular and intracellular spaces.

59
Q

What is the plasmalemma?

A

A plasma membrane allowing the cytosol to have vastly different chemical composition from the fluid surrounding the cell

60
Q

___ and ___ are embedded in the two lipid bi layers

A

protein channels and pumps

61
Q

Plasmalemma embedded proteins can be both ___ and ___

A

extrinsic (peripheral) and intrinsic(transmembrane- exposure to both in/out)

62
Q

Where are junctional folds in the plasmalemma concentrated?

A

Near motor end plate

63
Q

What functions can embedded plasmalemma proteins serve?

A

Transport system for nutrients, ion channels, adenylate cyclase, kinases, hormone receptors

64
Q

The cytoskeleton reinforces what? What does the cytoskeleton hold in place?

A

the plasmalemma

Organelles such as the nuclei and mitochondria

65
Q

What are satellite cells?

A

Undifferentiated myonucleated cell which is used to repair/recover from injury

66
Q

Where do satellite cells exist?

A

beneath basement membrane and outside plasma membrane

67
Q

What is the order of connective tissue surrounding different parts of the muscle?

A

Epimysium surrounds the muscle , perimysium surrounds the fasicles and endomysium surrounds the muscle fibers

68
Q

What function does the connective tissue serve?

A

Scaffolding for muscle development and resists excessive passive stretch and distributes force

69
Q

What proteins are utilized for attachment of myofibrils near the tendon?

A

Vinculin, Talin, Paxillin, and Tensin

70
Q

What is the basement membrane?

A

The glycoprotein complex surrounding muscle fiber lying between plasmalemma and endomysisum

71
Q

What makes up the sarcolemma?

A

The basement membrane(out) and plasma membrane(in)

72
Q

What enzymatic action occurs in basement membrane? What is the function of this?

A

acetylcholinesterase

Synaptic transmission termination

73
Q

What trophic functions does the basement membrane provide?

A

development and innervation

74
Q

What three layers make up the basement membrane?

A

Outward-in: reticular lamina, lamina densa and lamina lucida

75
Q

What are the components of the basement membrane?

A

acetylcholinesterase, collagen, fibronectin and tenascin

76
Q

What major regeneration function is associated with being just below the basement membrane?

A

satellite cells

77
Q

What are the four phases of muscular development?

A

Axonal outgrowth, myogenesis, synaptogenesis and synapse elimination

78
Q

What is the first step in muscle formation?

A

mesoderm is induced from ectoderm

79
Q

What is gastrulation?

A

The blastula invaginating itself to form the gastrula

80
Q

In terms of dorsal mesoderm and dorsal ectoderm, where do each stay? What Does the inner form?

A

Dorsal mesoderm lies beneath dorsal ectoderm and forms the CNS

81
Q

What is the second step in muscle formation?

A

A portion of the mesoderm forms somites, then develops into skeletal muscle

82
Q

During step two of muscle formation, where does the skeletal muscle develop?

A

Along the length of the embryo out of small clusters along the spine

83
Q

During embryonic development, what factors play a role and where?

A

Determination is the first half, which includes myoD and myf5. Differentiation is the second half, which includes mrf4 and Myogenin.

84
Q

What is the third step in muscle formation?

A

The myogenic cells proliferate and then differentiate

85
Q

Where does proliferation start during muscle formation?

A

Somites

86
Q

During stage 3 of muscular development, how are myoblasts classified?

A

Embryonic myoblast are primary
Fetal myoblast are secondary
Adult myoblast are satellite cells

87
Q

What comes first, proliferation or differentiation?

A

Proliferation then differentiation

88
Q

What extracellular signals are directing muscle development?

A

Sonic Hedgehog and WNT, Noggin, and bone morphogenic proteins

89
Q

When are myoblast formed and when do they fuse into myotubes?

A

Stage 3 of muscular development

90
Q

Name the events during and following myoblast fusion into myotube.

A

Nuclei align in center»>Synthesis of special proteins»>Formation of myofibrils»>Increased mitochondria»>Rudimentary T-tubule system»>SR from outer nuclear envelope

91
Q

Does a developing myotube plasmalemma have the to stimulate an AP?

A

Yes

92
Q

What type of receptors does the plasma membrane gain first?

A

ACh and cholinesterase

93
Q

What is stage 4 of muscular formation?

A

Homeotic genes define the shape of the embryo and appearance of major body features and Morphogenes are secreted based on the embryo position.

94
Q

What is stage 5 of muscular formation?

A

Division of muscle masses to form individual muscles

95
Q

What stage is fiber type determined?

A

5

96
Q

How is fiber typing determined during stage 5?

A

The myotubes can have slow or fast MHC (myosin heavy chain) types

97
Q

What are the 6 stages to development of muscle innervation?

A

1) Inductive signals from mesoderm->ectoderm
2) Neural tube forms
3) Nerve cells proliferate, then migrate
4) Axons grow out from the spinal cord
5) Axons establish connections with muscle fibers
6) Redundant synapse and motoneurons are eliminated

98
Q

When the NMJ is developing, what receptor type density increases?

A

ACH in post synaptic membrane