Sliding Filament Theory Flashcards
whats Sarcoplasm
cytoplasm of muscle fibres
whats Sarcoplasmic Reticulum
storage sites for calcium , surrounding myofibrils
Whats Tropomyosin
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)
Whats troponin
a protein attached to tropomyosin (acts as glue) , attachment site for Calcium ions (necessary for muscle contraction)
whats the sliding filament theory
how muscles contractions occurs
In the sliding filament theory wgat comes together
Z lines move closer together , actin moves not myosin
in the sliding filament theory what’s happening
Z lines move closer together, sarcomere shortens , actin filaments move in and slide over myosin filaments (myosin n actin filaments dont change in length
where does energy for sliding filament theory come from
ATP
What is happening in relaxed state of Sliding filament theory
-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
what happens in cross bridge step 1
- 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
what happens during Power Stroke step 2
The myosin head pulls back and moves actin with it
What happens in detachment step 3
ATP binds to the myosin head causing the myosin to let go of the actin
what happens in the step 4 hydrolysis
- 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
Where is energy for muscle contraction gained from
breakdown of creatine phosphate (anaerobic ), aerobic cellular respiration and lactic acid fermentation (anaerobic)
ATP is ____
ADP is _____
charged
not charged , lazy version
aerobic is
with O2
anaerobic is
without O2
whats creatine phosphate and whats it for
a high energy compound that builds up when muscle is resting and the fastest way to male ATP availableto muscles
how long does creatine phosphate provide energy
8 sec of intense activity and then it is spent
What does creatine phosphate initially do
supplies phosphate to ADP (not active) to get ATP before O2 enters mitochondria
Creatine Phosphate is a ________ system to get ATP energy
anaerobic (no O2)
Aerobic Cellular respiration takes cb place in _____
mitochondria
what dose aerobic cellular respiration do
provides most of the muscles ATP with O2
what happens during aerobic cellular respiration to create ATP
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
Myoglobin in muscle cells
stores O2 for use during muscle contraction
whats Lactic acid fermentation
a way to supply ATP in absence of oxygen
what happens due to lactic acid fermentation
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
What causes muscle fatigue
Oxygen debt
whats oxygen debt
when energy demand exceeds ATP supply , lactic acid accumulation
how does cramping occur
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
what do u need to make ATP
oxygen n glucose
how do u replenish oxygen defecit
replenishing creatine phosphate supplies and getting rid of lactate , rapid breathing after exercise is used to repay debt
whats rigor mortis
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
Another way to say atp
hydrolysis
Splitting of ____ provides energy for ____
ATP, muscle contraction
What does ATP do
allow for myosin head to detach and for muscle ti return ti relaxed state
whats released from sarcoplasmic reticulum during concetration
Ca++
What regenarate ATP
creatine phosphate, aerobic cellular respiration and lactic acid fermentation
whats a muscle twitch
a single contraction of muscle fibres from nerve impulse that lasts a mere fraction of a sec
what dose the contraction of a whole muscle vary on
strength depending on a number of muscles fibres contracting
contraction of a individual fibres is all or none once it reaches a certain ____
threshold
muscles twitch periods
1- catent
2- contraction
3- relaxation
whats the catent period of a muscle twitch
period of time for muscle to recive message from brain
whats the concentration period of a muscle twitch
period when muscle shortens
whats a relaxation period in a muscle twitch
when the muscles return to its formal lenght
whats summation
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
what does summation strength depend on
how close the second stimulus is to the first stimulus
What is tetanus
maximal sustained contraction when all muscle fibres are combined into one contraction
when tetanus occurs the graph starts ti show
one combined line showing combined strength of fibres
until when does tetanus continue to occur
until muscles fatigues due ti depletion of energy reserve (once ur ATP is gone)
muscle fibres type 1 is
slow twitch
muscle fibres type two is
fast twitch
what is type 1 muscle twitch
slow twitch, contract slow to resist fatigue, breakdown ATP slowly and efficiently, rely on aerobic cellular respiration, many mitochondria
what is type 2 muscle twitch
fast twitch that rely on rapid generation of power, breakdown ATP quickly and inefficiency, rely on anaerobic respiration (produce lactic acid) without 02
who is type 1 of muscle fibres found in
long distance runners , swimmers and bikers
who is type 2 of muscle fibres found in
sprinters and weightlifters
what decides the type of muscle fibres u have
ur genes n body shape
whats hypertrophy
increase jn size of skeletal muscle cells
whats atrophy
lack of usage causing a reduction in size of muscle
low intensity long duration training affects
slow twitch fibres type 1
high intensity short duration training affects
fast twitch fibres type 2
low intensity, long duration training does what
increases the number if mitochondria and blood vessels feeding the fibres , increases endurance(more energy)
high intensity, short duration training does what
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
