Bio Class 10 Flashcards

1
Q

Function of muscles

A

Voluntary control

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2
Q

Location of muscles

A

On bones

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3
Q

Nuclei in muscles

A

Multinucleated

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4
Q

Microscopic appearance of muscles

A

striated

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5
Q

Hierarchy of muscle composition

A

Protein filaments (actin & myosin) –> Sarcomere (arrangement of myosin & actin in a specific way) –> myofibril (sarcomere lined end to end) –> muscle cell fiber *myofiber (bundle of myofibrils + plasma membrane, some organelles, fibroblast) –> fasicle (bundle of myofiber) –> whole muscle (bundle of fasicles)

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6
Q

Which muscles have sarcomeres?

A

Cardiac muscles

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7
Q

Why do skeletal muscles have t-tubules?

A

Skeletal muscle is really thick so need T-tubules to carry AP deep into cell

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8
Q

H-zone

A

Region of only myosin

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9
Q

A band

A

Region of entire myosin with some actin

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10
Q

I band

A

Region of actin between each myosin

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11
Q

Z line

A

Beginning to end of each sarcomere

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12
Q

What happens to the sarcomere upon contraction?

A

H zone & I band will disappear, A band will remain the same; myosin will attach to actin and pull it closer bringing the Z line closer to myosin each time

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13
Q

Sliding Filament Theory

A
  1. Myosin head will bind to actin in presence of Ca2+; also called “cross bridge formation”
  2. Myosin pulls actin towards center of sarcomere; called “power stroke” but NO ATP
  3. In presence of ATP, myosin will bind to ATP and release actin
  4. Myosin resets to high energy conformation; requires ATP hydrolysis

After each round of steps 1-4, Z line will get closer and closer to thick filament

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14
Q

Excitation-Contraction Coupling

A

Tropomyosin binds to actin and blocks the sites of myosin binding

  • tropomyosin is attached to troponin which has a binding site for Ca2+
  • When Ca2+ is present, troponin will make tropomyosin move apart, unblocking the myosin sites which will allow contraction to happen
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15
Q

What happens to muscles when you run out of ATP?

A

You can’t relax, myosin will stay bound to actin and you will stay contracted

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16
Q

Do myosin heads operate asynchronously or synchronously?

A

Asynchronously because if they worked in the same way then they would all bind to actin at the same time & release at same time so the Z line will just snap back to its original position

17
Q

Bohr-shift

A

Shift to right:
increases carbon dioxide
increases temperature
decreases pH

18
Q

What happens to oxygen affinity & delivery during exercise?

A

Hb affinity to o2 during exercises decreases, while delivery to tissues increases
- will shift to the right

19
Q

Motor Unit

A

motor neuron and all muscle cells under its control

20
Q

Large Motor unit vs small motor unit

A

Large
- 1000 muscle cells per neuron

Small
- 10-20 muscle cells per neuron

21
Q

Gross vs fine motor control

A

Gross

  • Eg. big scale movements like running
  • few large motor units

Fine

  • Eg. precision so things like eye movement
  • many many small motor units
22
Q

How can you address oxygen debt?

A
  1. Replenish oxygen on myoglobin
  2. Convert lactic acid to something useful (so you want to oxidize lactic acid back to pyruvate or maybe even all the way to glucose through gluconeogenesis)
23
Q

Muscle Energy Sources

A
  1. Creatine-P + ADP –> Creatine + ATP
  2. Glycolysis
  3. Aerobic Respiration (Krebs, PDC, ETC)
24
Q

Myoglobin

A

Stores oxygen

- one polypeptide so no cooperative binding

25
Q

Fiber Types

A

Slow twitch
Fast Twitch Type IIA
Fast Twitch Type IIB

26
Q
Slow Twitch:
Myoglobin Content
Capillary Network
Speed of contraction
Mitochondrial #
Fatigue resistance
Force generated
Example
A
  • also known as “red slow twitch or red oxidative fibers”
  • high with myoglobinc
  • dense capillary network
  • slow contaction
  • high mito #
  • extended contraction with no fatigue
  • low force
  • Eg. Leg muscle of marathon runner
27
Q
Fast Twitch Type IIa:
Myoglobin Content
Capillary Network
Speed of contraction
Mitochondrial #
Fatigue resistance
Force generated
Example
A
  • also known as “fast twitch oxidative fibers”
  • lower myoglobin
  • less dense capillary network
  • intermediate contraction
  • some mito #
  • ~30 mins
  • medium force
  • Eg. Leg muscle of 400 m fast runner
28
Q
Fast Twitch Type IIb:
Myoglobin Content
Capillary Network
Speed of contraction
Mitochondrial #
Fatigue resistance
Force generated
Example
A
  • also known as “white fast twitch fibers”
  • very low myoglobin
  • very few capillary network
  • fast contraction
  • very few mito #
  • ~1 min
  • explosive force
  • Eg. Chicken breasts
29
Q

Cardiac vs Smooth Muscle

A

Cardiac

  • uninucleated
  • involuntary
  • in heart
  • striated (actin & myosin organized into sarcomeres)

Smooth

  • uninucleated
  • involuntary
  • walls of hollow organs
  • nonstriated (myosin and actin randomly in place)
30
Q

_____blast vs _____cyte

A
  • blast:
  • still dividing
  • produces the matrix
  • immature bone cells
  • cyte:
  • not dividing
  • maintains matrix
  • mature bone cells
31
Q

What is the matrix composed of?

A
Fibers (elastic or collagen)
Glop substance (liquid = plasma, solid = bone)
32
Q

Bone function (skeletal system function)

A
  1. Support & movement
  2. Protection
  3. Mineral storage
  4. Blood cell formation
33
Q

Long Bone anatomy

A

2 epiphysis & a diaphysis

  • epihysis is protruding end with spongy bone
  • diaphysis is composed of compact bone