Sliding Filament Theory Flashcards

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1
Q

whats Sarcoplasm

A

cytoplasm of muscle fibres

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2
Q

whats Sarcoplasmic Reticulum

A

storage sites for calcium , surrounding myofibrils

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3
Q

Whats Tropomyosin

A

long protein filament that blocks or exposes the binding sites of myosin heads , bands that run along the actin filament ( allows muscles to relax by attaching to actin)

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4
Q

Whats troponin

A

a protein attached to tropomyosin (acts as glue) , attachment site for Calcium ions (necessary for muscle contraction)

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5
Q

whats the sliding filament theory

A

how muscles contractions occurs

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6
Q

In the sliding filament theory wgat comes together

A

Z lines move closer together , actin moves not myosin

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7
Q

in the sliding filament theory what’s happening

A

Z lines move closer together, sarcomere shortens , actin filaments move in and slide over myosin filaments (myosin n actin filaments dont change in length

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8
Q

where does energy for sliding filament theory come from

A

ATP

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9
Q

What is happening in relaxed state of Sliding filament theory

A

-Myosin head is not contacting the actin
- Calcium is absent
- Tropomyosin blocks the myosin binding sites on actin
- tropomyosin is held in position by troponin

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10
Q

what happens in cross bridge step 1

A
  • Calcium ions are released from the sarcolemma upon stimulation
  • Calcium binds to troponin (makes it not sticky) and moves the tropomyosin away from the binding sites
  • the heads of myosin attach to binding sites on the actin filaments
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11
Q

what happens during Power Stroke step 2

A

The myosin head pulls back and moves actin with it

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12
Q

What happens in detachment step 3

A

ATP binds to the myosin head causing the myosin to let go of the actin

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13
Q

what happens in the step 4 hydrolysis

A
  • when ATP binds to myosin it breaks down into ADP , Pi and energy
  • Calcium detaches from troponin and is reabsorbed
  • Tropomyosin moves back ti its original position and blocks the myosin binding sites again
  • Creatine Phosphate regenerates ATP
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14
Q

Where is energy for muscle contraction gained from

A

breakdown of creatine phosphate (anaerobic ), aerobic cellular respiration and lactic acid fermentation (anaerobic)

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15
Q

ATP is ____
ADP is _____

A

charged
not charged , lazy version

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16
Q

aerobic is

A

with O2

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17
Q

anaerobic is

A

without O2

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18
Q

whats creatine phosphate and whats it for

A

a high energy compound that builds up when muscle is resting and the fastest way to male ATP availableto muscles

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19
Q

how long does creatine phosphate provide energy

A

8 sec of intense activity and then it is spent

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20
Q

What does creatine phosphate initially do

A

supplies phosphate to ADP (not active) to get ATP before O2 enters mitochondria

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21
Q

Creatine Phosphate is a ________ system to get ATP energy

A

anaerobic (no O2)

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22
Q

Aerobic Cellular respiration takes cb place in _____

A

mitochondria

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23
Q

what dose aerobic cellular respiration do

A

provides most of the muscles ATP with O2

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24
Q

what happens during aerobic cellular respiration to create ATP

A

glycogen and fats are stored in muscle cells to be used a fuel to produce ATP when O2 is available
Myoglobin in muscle cells stores oxygen during muscle contraction
CO2 water n heat r produced as wastes

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25
Q

Myoglobin in muscle cells

A

stores O2 for use during muscle contraction

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26
Q

whats Lactic acid fermentation

A

a way to supply ATP in absence of oxygen

27
Q

what happens due to lactic acid fermentation

A

lactate(lactic acid) is produced which makes sarcoplasm more acidic which when accumulated for more than 2 min causes muscles cramping and fatigue resulting in oxygen defect

28
Q

What causes muscle fatigue

A

Oxygen debt

29
Q

whats oxygen debt

A

when energy demand exceeds ATP supply , lactic acid accumulation

30
Q

how does cramping occur

A

from the lack of ATP to pump calcium ions back into sarcoplasmic reticulum and break of linkage between myosin n actin si that muscle fibres can relax

31
Q

what do u need to make ATP

A

oxygen n glucose

32
Q

how do u replenish oxygen defecit

A

replenishing creatine phosphate supplies and getting rid of lactate , rapid breathing after exercise is used to repay debt

33
Q

whats rigor mortis

A

moments after up to 60 hrs after death when ATP production ceases and skeletal muscles become fixed (stiff as a board) , cross bridges fail to detach

34
Q

Another way to say atp

A

hydrolysis

35
Q

Splitting of ____ provides energy for ____

A

ATP, muscle contraction

36
Q

What does ATP do

A

allow for myosin head to detach and for muscle ti return ti relaxed state

37
Q

whats released from sarcoplasmic reticulum during concetration

A

Ca++

38
Q

What regenarate ATP

A

creatine phosphate, aerobic cellular respiration and lactic acid fermentation

39
Q

whats a muscle twitch

A

a single contraction of muscle fibres from nerve impulse that lasts a mere fraction of a sec

40
Q

what dose the contraction of a whole muscle vary on

A

strength depending on a number of muscles fibres contracting

41
Q

contraction of a individual fibres is all or none once it reaches a certain ____

A

threshold

42
Q

muscles twitch periods

A

1- catent
2- contraction
3- relaxation

43
Q

whats the catent period of a muscle twitch

A

period of time for muscle to recive message from brain

44
Q

whats the concentration period of a muscle twitch

A

period when muscle shortens

45
Q

whats a relaxation period in a muscle twitch

A

when the muscles return to its formal lenght

46
Q

whats summation

A

When a muscle is given rapid series of threshold stimuli ( way of ur brain sending msg to ur muscles) to stimulate more or less fibres ti produce more or less force

47
Q

what does summation strength depend on

A

how close the second stimulus is to the first stimulus

48
Q

What is tetanus

A

maximal sustained contraction when all muscle fibres are combined into one contraction

49
Q

when tetanus occurs the graph starts ti show

A

one combined line showing combined strength of fibres

50
Q

until when does tetanus continue to occur

A

until muscles fatigues due ti depletion of energy reserve (once ur ATP is gone)

51
Q

muscle fibres type 1 is

A

slow twitch

52
Q

muscle fibres type two is

A

fast twitch

53
Q

what is type 1 muscle twitch

A

slow twitch, contract slow to resist fatigue, breakdown ATP slowly and efficiently, rely on aerobic cellular respiration, many mitochondria

54
Q

what is type 2 muscle twitch

A

fast twitch that rely on rapid generation of power, breakdown ATP quickly and inefficiency, rely on anaerobic respiration (produce lactic acid) without 02

55
Q

who is type 1 of muscle fibres found in

A

long distance runners , swimmers and bikers

56
Q

who is type 2 of muscle fibres found in

A

sprinters and weightlifters

57
Q

what decides the type of muscle fibres u have

A

ur genes n body shape

58
Q

whats hypertrophy

A

increase jn size of skeletal muscle cells

59
Q

whats atrophy

A

lack of usage causing a reduction in size of muscle

60
Q

low intensity long duration training affects

A

slow twitch fibres type 1

61
Q

high intensity short duration training affects

A

fast twitch fibres type 2

62
Q

low intensity, long duration training does what

A

increases the number if mitochondria and blood vessels feeding the fibres , increases endurance(more energy)

63
Q

high intensity, short duration training does what

A

affects fast twitch muscles and causes them to increase in diameter(add more actin n myosin) , increases strength and muscles but does not improve endurance