Exam 4 Flashcards

SKELETAL MUSCLES & PHYSICAL PERFORMANCE

1
Q

Myology

A

scientific study of muscles & their parts

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2
Q

Generally speaking, 2 main units exist in the muscular system… what are they?

A

structural unit: muscle fiber or muscle cell

functional unit: motor unit

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3
Q

Skeletal muscle fibers are comprised of 2 primary constituents

A
  • sarcoplasm: muscle cytoplasm

- myofibrils: sarcomeres in series-contractile elements

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4
Q

Gross muscles may be comprised of how many muscle fibers?

A

only a few or as many as 1 million

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5
Q

Structural unit

A

muscle fiber/muscle cell

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6
Q

Functional unit

A

motor unit

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7
Q

All muscle fibers are supplied with nerves (innervated) by terminal branches of a single ___ ___ ___?

A

alpha efferent axon

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8
Q

How many motor units are located in each gross muscle?

A

multiple

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9
Q

What does it mean if a motor unit is recruited?

A

all fibers w/in it are concurrently contracting

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10
Q

As force demands increase…

A

more motor units are recruited

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11
Q

Muscles containing a small # of muscle fibers per motor unit are capable of smaller/larger gradations (degrees, stages) in force output?

A

smaller

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12
Q

Sarcoplasm

A

~25% protein in a non-contractile configuration

~75% fluid

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13
Q

Myofibrils

A

various protein filaments configured to enable the contractile process

-series of sarcomeres

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14
Q

Main filaments involved in contractions

A

myosin & actin

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15
Q

Smaller filaments loosely bound to actin when the myofibril is relaxed

A

troponin & tropomyosin

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16
Q

Muscle fibers have how many nuclei?

A

multiple

multi-nucleated

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17
Q

Muscle fibers have a cell wall called the…

A

sarcolemma

18
Q

Sarcolemmas have 3 major substructures:

A
  • Transverse Tubules (T Tubules)
  • Terminal Cisternae
  • Sarcoplasmic Reticulum (SR)
19
Q

Transverse Tubules

A
  • inlets w/in the sarcolemma that provide for neural input

- Run roughly perpendicular to sarcomere

20
Q

Terminal Cisternae

A
  • Storage vesicles for calcium
  • Located parallel & contiguous (share a border) to transverse tubules
  • May be referred to as vesicles of the SR
21
Q

Sarcoplasmic Reticulum

A
  • conduit for calcium

- oriented roughly parallel to the sarcomere

22
Q

Sarcomere

A

structural unit of the myofibril

23
Q

Sarcomere contains the contractile elements between each pair of ___?

A

Z-disks

24
Q

Z-disks are ___ ____?

A

connective tissue

25
Q

In a relaxed sarcomere you have the following…

A

I-band
A-band
H-zone
M-line

26
Q

I-band

A

light zone

27
Q

A-band

A

dark zone

28
Q

H-zone

A

in middle of A-band

29
Q

M-line

A

in middle of H-zone

30
Q

Connective tissue found within each ___ ____ and at ___ ____ outside of it.

A

muscle fiber

multiple levels

31
Q

Connects sarcomeres?

A

z line / z disc

32
Q

Endomysium surrounds…

A

surrounds muscle fibers

33
Q

Perimysium surrounds…

A

surrounds fascicles

34
Q

Epimysium/fascia surrounds…

A

surrounds whole muscle

35
Q

Tendon is…

A

coalescing (coming together of) of epimysium and fascia that connects muscle to bone

36
Q

2 main types of extracellular protein fiber that affect elasticity of musculo-tendinous unit

A

collagen & elastin

37
Q

Collagen

A
  • fibrous insoluble protein
  • found within connective tissue in muscle, skin, bone, ligaments, & cartilage
  • stiffens tissue
  • greater than or equal to 20 isoforms exist
38
Q

Elastin

A
  • stores mechanical energy

- albuminoid protein (yellow elastic tissue found in connective tissue)

39
Q

Connective tissue fill where?

A

spaces b/w organs & tissues in the body

40
Q

Connective tissue mainly comprised of

A
  • tough protein fibers embedded in a polysaccaride gel (extracellular matrix)
  • mainly secreted by fibroblasts
41
Q

Parallel elastic components made up of…

A
  • sarcolemma
  • endomysium
  • perimysium
  • epimysium
42
Q

Other tissues that affect elasticity of musculo-tendinous unit

A
  • parallel elastic components

- series elastic components