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Principles of Biology II > Chapter 38 Musculoskeletal System > Flashcards

Chapter 38 Musculoskeletal System Flashcards

1
Q

The powerstroke in muscle cells occurs when ___.

A

inorganic phosphate is released from myosin

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2
Q

True or False: Skeletal muscle cells produce action potentials.

A

True

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3
Q

When a muscle cell is stimulated to contract, the sarcoplasmic reticulum releases ____.

A

calcium ions

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4
Q

____ is the protein that physically blocks the myosin binding sites on the thin filaments.

A

trompomyosin

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5
Q

Which of the following types of muscles has(have) contractile proteins organized into sarcomeres and are striated muscles?

A

cardiac and skeletal

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6
Q

The “tubes of protein” that are bundles of the contractile proteins found in striated muscle are called ____.

A

thin filaments

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7
Q

How do muscle fibers shorten during contraction?

A

Two types of protein filaments overlap and slide past each other.

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8
Q

What muscle type is voluntary?

A

skeletal

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9
Q

Skeletal systems are important for ___.

A

movement

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10
Q

The striated appearance of muscle is due to the ____.

A

organization of the sarcoplasmic reticulum

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11
Q

True or False: Muscles can contract and relax.

A

True

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12
Q

What needs to happen with muscles in order for movement to occur?

A

they need something to pull on

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13
Q

What are bone and cartilage part of?

A

endoskeletons

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14
Q

3 Types of Skeletons

A
  • hydrostatic
  • exoskeleton
  • endoskeleton
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15
Q

Hydrostatic Skeleton

A

formed by a fluid-filled compartment within the body

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16
Q

Exoskeleton

A

external skeleton on the surface of the animal

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17
Q

Example of an Animal with an Exoskeleton

A

arthropods (spiders)

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18
Q

Endoskeleton

A

hard mineralized structures within soft tissues

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19
Q

Primitive endoskeletons include spicules of ___.

A

sponges

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20
Q

coelom

A

fluid-filled body cavity

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21
Q

What are muscles responsible for?

A

tissue movement

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22
Q

True or False: All animals have muscle.

A

False

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23
Q

What animals do NOT have muscle?

A

sponges and cnidarians

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24
Q

3 Types of Muscle

A
  • skeletal
  • cardiac
  • smooth
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25
Characteristics of Skeletal Muscle
- voluntary and involuntary movement of breathing - contain sarcomeres - multinucleated
26
Characteristics of Cardiac Muscle
- heart contraction; involuntary - contains sarcomeres and intercalated discs - branched
27
Characteristics of Smooth Muscle
- involuntary - movement in gut, bladder, and blood vessels - do not contain sarcomeres
28
How do non-striated muscles differ from striated muscles?
the presence of sarcomeres
29
Myofibril
tightly packed filament bundles
30
Myocyte
muscle cell
31
Muscle fiber
muscle cell
32
Are skeletal muscle cells multinucleated?
YES
33
Characteristics of a Sarcomere
- unit of contraction - these units repeat
34
What are thick filaments made of?
myosin
35
What are thin filaments made of?
actin
36
2 Types of Contractile Proteins
actin and myosin
37
Sliding Filament Theory
filaments slide past each other whenever contraction occurs
38
The length of the sarcomere is related to ___.
how much force can be produced
39
Is length related to overlap in the sarcomere?
YES
40
Too much overlap ___.
nowhere for the myosin to move the actin
41
Too little overlap ___.
myosin can't grab actin
42
Neuromuscular Junction
point of contact between a motor neuron and a skeletal muscle cell
43
Motor Unit
a motor neuron and all of the muscle fibers it innervates
44
Motor Neuron
a neuron that sends an impulse to a muscle
45
Can a motor neuron terminate on multiple muscle cells?
YES
46
Sarcoplasmic Reticulum
endoplasmic reticulum inside a muscle cell
47
Sarcoplasmic reticulum stores ___.
calcium
48
Where does depolarization start in muscle cells?
ligand gated channels
49
What ion enters into a skeletal muscle cell to create and action potential?
Na+ (sodium)
50
What does the action potential in a muscle cell cause to be released from the sarcoplasmic reticulum?
calcium
51
Characteristics of Myosin
- multiple subunits - place of ATPase activity
52
Characteristics of Actin Filament
- actin monomers - myosin binding site
53
2 Types of Regulatory Proteins in Muscles
tropomyosin and troponin
54
Characteristics of Troponin
- binds calcium ions - interacts with tropomyosin
55
Tropomyosin
blocks myosin binding site
56
What is released to cause a powerstroke in muscle contraction?
phosphate
57
What is rigor?
stiffening due to death of muscle
58
What does calcium bind to?
troponin
59
When calcium bind to troponin, what does troponin do?
the troponin reveals the myosin binding site by removing tropomyosin
60
What causes myosin to release actin?
ATP binding to the myosin
61
What causes the myosin head to cock forward?
ATP being broken down into ADP
62
Characteristics of Slow-Twitch Muscle Cells
- red, oxidative fibers - aerobic - has many mitochondria - contains myoglobin
63
Characteristics of Fast-Twitch Muscle Cells
- white, glycolytic fibers - anaerobic - fewer mitochondria - do NOT contain myoglobin
64
The neurotransmitter _____ binds to receptors in plasma membrane of a muscle cell to stimulate contraction.
Acetylcholine
65
What is the role of calcium ions in the control of muscle contraction?
it bind to troponin to stimulate contraction
66
Which muscle protein hydrolyzes ATP to stimulate muscle contraction?
myosin
67
A pair of closely related bird species includes one that migrates long distances that takes months and another that has evolved near-flightlessness on its island home, with the exception of short flights to escape its predators. What might you expect to find when comparing the breast muscles that are used for flight of these two species?
The migratory species would have relatively higher levels of myoglobin.
68
When animals die, the lack of ATP causes muscles to stiffen in rigor mortis because ____.
Actin and myosin cannot separate from each other without ATP
69
Examine the picture below. This capillary could be in a____. This is because ___.
skeletal muscle.... carbon dioxide is diffusing from the tissue labeled 1 into the plasma
70
True or False: When a muscle cell shortens, the amount of overlap between the thick and thin filament decreases.
False

Principles of Biology II (7 decks)

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