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Human Structure and Function 1 > EXAM 3 > Flashcards

EXAM 3 Flashcards

1
Q

What are some additional functions of muscles? (4)

A
  • protects organs
  • forms valves
  • controls pupil size
  • causes “goosebumps”
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2
Q

What are the 3 types of muscle tissue?

A
  • skeletal
  • cardiac
  • smooth
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3
Q

What are the 4 main muscle functions?

A
  • moves bones
  • maintains posture
  • stabilizes
  • heat generation (esp. skeletal muscle)
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4
Q

In skeletal muscle, every (1) is supplied by a (2) that (3). There is a huge (4) and (5) need. Which means there is (6).

A
  1. muscle fiber
  2. nerve ending
  3. controls activity
  4. nutrient
  5. oxygen
  6. much waste
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5
Q

Define sarcoplasm

A

the cytoplasm of the muscle cell

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6
Q

ULTRASTRUCTURE OF THIN FILAMENT

  • composed chiefly of the protein [1]
  • actin has kidney-shaped polypeptide subunits, called [2] aka, [3]
    • has a myosin-binding site (or [4]) to which the myosin heads attach during [5]
    • G actin subunits polymerize into long actin filaments called [6] (F actin)
  • [7] intertwined actin filaments, resembling a twisted double strand of pearls, form the backbone of each [8]
  • thin filaments also contain several regulatory proteins: [9] and [10]
A
  1. actin
  2. globular actin
  3. G actin
  4. active site
  5. contraction
  6. filamentous actin
  7. two
  8. thin filament
  9. tropmyosin
  10. troponin
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7
Q

SUFFIX

-plasmic

A

material making cells

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8
Q

SUFFIX

-filament

A

thread

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9
Q

SLIDING FILAMENT MODEL OF CONTRACTION

When the nervous system stimulates muscle fibers, the [1] on the [2] latch onto [3] on [4] in the [5], and the [6].

These cross bridge attachments [7] several times during a contraction, acting like tiny ratchets to [8] and propel the thin filaments toward [9] of the [10].

As this event occurs simultaneously in sarcomeres throughout the cell, the muscle cell [11].

A
  1. myosin heads
  2. thick filaments
  3. myosin-binding sites
  4. actin
  5. thin filaments
  6. sliding begins
  7. form and break
  8. generate tension
  9. the center
  10. sarcomere
  11. shortens
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10
Q

PREFIX

epi-

A

over

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11
Q

What are the functions of the skeletal muscle connective tissue sheaths? (2)

A
  1. support the cells
  2. reinforce and together the muscle
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12
Q

STEPS OF A MUSCLE CONTRACTION

  1. nerve impulse reaches axon terminal bulb
  2. voltage-gated calcium channels open
  3. ACh released to synaptic cleft
  4. ACh binds to receptor on sarcolemma
  5. Na+ floods into muscle fiber → depolarization
  6. depolarization spreads to nearby voltage-gated Na+ and K+ channels → action potential moves along sarcolemma
  7. action potential reached T-tubules
  8. voltage sensitive T-tubule proteins change shape → calcium channels open
  9. calcium is released to muscle fiber sarcoplasm
  10. calcium binds to troponin on thin filament → troponin changes shape
  11. altered troponin → tropomyosin shifts exposing binding sites on actin
  12. myosin can now form a cross-bridge with actin to allow contraction
A

just keep clicking 1 until you have looked at this enough

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13
Q

Name the two sets of intracellular tubules that help regulate muscle contraction.

A
  1. sarcoplasmic reticulum
  2. T-tubules
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14
Q

The globular heads, each associated with two light chains, are the “business end” of myosin. During contraction, they link the [1] and [2] filaments together, forming [3], and [4] around their point of attachment, acting as motors to [5]. Myosin itself [6] (acts as an ATPase) and uses the [7] to drive movement.

A
  1. thick
  2. thin
  3. cross bridges
  4. swivel
  5. generate force
  6. splits ATP
  7. released energy
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15
Q

Describe the epimysium. (3)

A
  • dense irregular CT
  • surrounds muscle
  • sometimes blends into deep fascia
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16
Q

TERMS

  1. fascia
  2. fascicle
A
  1. sheet of connective tissue
  2. bundle of structures
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17
Q

What are the three modified structures in a muscle fiber?

A
  1. sarcoplasmic reticulum (stores Ca2+)
  2. T-tubules
  3. myofibrils
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18
Q

Muscle tissue makes up how much of body mass?

A

Half of all body mass

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19
Q

DEFINE

  1. origin
  2. insertion
A
  1. attachment to the immovable (less movable) bone
  2. attachment to the movable bone
20
Q

What is a fascicle? (2)

A
  • discrete bundle of muscle cells
  • surrounded by perimysium
21
Q

The integral proteins of the (1) form (2) through which the (3) release (4).

A
  1. sarcoplasmic reticulum
  2. gated channels
  3. terminal cisterns
  4. Ca2+
22
Q

For skeletal muscle to contract:

  • [1] (at [2])
    • Nervous system stimulation required
    • Must generate action potential in [3]
  • [4]
    • Action potential [5] along sarcolemma
    • Intracellular Ca2+ levels must [6]
A
  1. activation
  2. neuromuscular junction
  3. sarcolemma
  4. excitation-contraction coupling
  5. propagated
  6. rise briefly
23
Q

What is the sarcolemma?

A

plasma membrane of the muscle cell (important to signalling)

24
Q

PREFIX

endo-

A

inner

25
Q

PREFIX

peri-

A

around

26
Q

SUFFIX

-reticulum

A

network

27
Q

ULTRASTRUCTURE OF THICK FILAMENT

  • Composed of [1] (protein): [2] + [3] polypeptide chains
    • Myosin tails: [4] polypeptide chains interwoven
    • Myosin heads: [5] chains: [6] during contraction
  • Binding sites for
    • [7]
    • [8]
  • each head acts as [9]
A
  1. myosin
  2. 2 heavy
  3. 4 light
  4. 2 heavy
  5. 2 smaller, light
  6. cross bridges
  7. thin filament actin
  8. ATP
  9. ATPase enzymes
28
Q

Skeletal muscle: each: ? artery + ? nerve + 1/more veins

A

1; 1

29
Q

What is a muscle fiber? (3)

A
  • elongated, multinucleate cell
  • striated appearance
  • surrounded by endomysium
30
Q

(1) are perfectly aligned repeating series of dark (2) and light (3) due to overlap of proteins in (4).

A
  1. striations
  2. A bands
  3. I bands
  4. myfilaments
31
Q

Name the two storage organelles in the muscle fiber and their function.

A
  1. ​glycosome: stores glycogen
  2. myoglobin: stores oxygen
32
Q

Describe the sarcoplasmic reticulum. (5)

A
  • elaborate smooth endoplasmic reticulum
  • network around each myofibril
  • longitudinal along myofibril
  • stores / releases Ca2+
  • regulates intracellular levels of Ca2+
33
Q

Describe the perimysium. (2)

A
  • dense irregular CT
  • surrounds fascicles
34
Q

Describe the terminal cisternae. (2)

A
  • perpendicular cross channels
  • forms part of the triad
35
Q

Describe the thick filament.

A
  • run length of A band
  • myosin
  • connected at M line
36
Q

Describe the endomysium. (2)

A
  • surrounds each individual muscle fiber
  • fine areolar CT
37
Q

What is the resting membrane potential?

A
  • produced by separation of oppositely charged particles across membrane in all cells
    • negative = inside membrane
    • positive = outside membrane
  • cells = polarized
  • voltage is ONLY at the membrane
    • intra/extracellular surfaces
    • -50 to -100 mV in different cells
  • selective diffusion
38
Q

Describe the T-tubules. (5)

A
  • continuous w/ sarcolemma
  • lumen continuous w/ extracellular space
  • increase muscle fiber’s surface area
  • penetrates interior at each A-band/I-band junction
  • middle part of triad
39
Q

What are the 4 characteristics of muscle tissue?

A
  • excitability
  • contractility
  • extensibility
  • elasticity
40
Q

Define the types of attachments:

  1. direct
  2. indirect
A
  1. direct - epimysium fused to periosteum/perichondrium
  2. indirect - CT wrappings extend beyond muscle as tendon or aponeurosis
41
Q

What is a sarcomere?

A
  • contractile units of muscle fiber
  • contains myfilaments
  • region between two Z discs
42
Q

(1) conduct impulses deep into the (2) and (3).

A
  1. T tubules
  2. muscle fiber
  3. sarcomere
43
Q

What is a myofibril? (5)

A
  • rodlike contractile elements
  • occupies most of muscle volume
  • composed of sarcomeres from end to end
  • ~80% of cell volume
  • modified structure
44
Q

At the microscopic level, the following things occur as a muscle cell shortens:

  • The [1] shorten.
  • The distance between successive [2] shortens. As the [3] slide centrally, the [4] to which they attach are pulled toward the [5]
  • The [6] disappear.
  • The contiguous A bands move [7] together, but their length [8].
A
  1. I bands
  2. Z discs
  3. thin filaments
  4. Z discs
  5. M line
  6. H zones
  7. closer
  8. does not change
45
Q

ROOTS

  • myo
  • sarco
A

muscle

46
Q

SUFFIX

-fibril

A

fiber

47
Q

Describe the microscopic anatomy of the muscle cell. (3)

A
  • 10 - 100 µm diameter
  • up to 30 cm long
  • multiple peripheral nuclei

Human Structure and Function 1 (5 decks)

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