Exam 8: March 6-8 Flashcards
how much ATP does one CBC take?
1 ATP per CBC
how far does one ATP during CBC get you?
10 micrometers per ATP
so to get our big movements it’ll cost us a lot of ATP to get our hand all the way up to our shoulder
what do you need ATP for during muscle movement?
1) we need ATP to unbind and we use the energy from it to do two parts: to reach out (where we hang on to residual energy) and we use the rest of the energy to pull – we don’t have to use all the energy at once, we can use it in multiple components
2) we also need ATP to stop the tension because we need it to run the ATPase pump that puts Ca back to the SR – we have a pool of Ca that stays inside the cell but isn’t in the cytosol anymore and we have to put it back to the SR so it can’t bind to the troponin
how do we make ATP in our muscles?
substrate level phosphorylation; glycolysis, Krebs, and creatine phosphate
oxidative phosphorylation: ETC
what is substrate level phosphorylation?
XP + ADP –> ATP + X
how does creatine phosphate work? what’s the equation for it?
substrate level phosphorylation
XP + ADP –> ATP + X
where X is creatine so you have creatine left at the end
it’s equation 1 so our cell doesn’t need oxygen
how much ATP do get per creatine phosphate?
for every creatine phosphate we can only get 1 ATP
what’s the problem with creatine phosphate as an ATP source?
1:1 relationship creates a problem because we can’t have that much creatin phosphate in our myofiber
raising the number of things inside our myofiber would cause an osmolarity problem and water to go into the cells so our cell will swell which is how people with muscles look so big
what is creatine phosphate useful for?
it can’t be our dominant source of ATP but it’s a nice initial source of ATP because it’s just a one step process
glycolysis is 10 steps and glycolysis is 8 steps so they take a while to kick in
when we rest we replenish our amount of creatin phosphate but we use it up very quickly once we need it – creatin phosphate is just for the initial burst like standing up and taking a couple steps
how many steps is glycolysis?
10 steps which takes more time
this is why we need creatine phosphate initially
how much ATP and movement do you get per glucose in glycolysis?
2 ATP for every glucose so 20 micrometers of movement
still not a lot of movement
what’s the problem with glycolysis?
we’re running off of glucose and glucose comes to cell from the blood which also carries oxygen
you could pack up the cells with glucose to be broken up in the cell but we can’t because we again create an osmolarity problem
how is the problem with glucose in glycolysis solves?
you take the glucose and chain them together like cars in a train = glycogen
osmolarity is about the number of things so chaining together 15 glucose counts as just one thing (can’t do this with creatin phosphate)
in this way you avoid the osmolarity problem aka glycogen storage
what is the point of carb loading?
carbs are glucose
what they’re doing is bringing glucose into their body and having their muscles turn it into glycogen so you store it
you get big amounts of glucose and when you need glucose, you just pop one off the chain and use it in glycolysis and you avoid the osmolarity problem this way
what happens when you run glycolysis anaerobically? when are you in these situations?
you get lactic acid instead of pyruvate
intense activity is where we require the muscle to be creating ATP at a rate that the blood can’t supply enough oxygen to stay aerobic
what are the types of anaerobic activity?
1) big, short busts of energy where you use up the oxygen supply
2) prolonged activity because you work so long that you use up all the oxygen that’s there
what kind of activity is weight lifting?
anaerobic activity because it’s a big, short burst where you’re trying to get a lot of activity in a short amount of time where you use up the oxygen supply
what’s the problem with anaerobic activity? what happens to lactic acid?
you can’t sustain it very long because you’re still just making 2 ATP from glycolysis
while our muscles are resting we can clear out the lactic acid – our muscles can’t directly use the lactic acid, we have to move it out of our muscles and our liver will break it down
what type of reaction is Krebs cycle?
substrate level phosphorylation
how much ATP and movement does Krebs cycle get us?
2 ATP = 20 micrometers
does Krebs need oxygen?
yes! if you take away oxygen you won’t have Krebs because no pyruvate is being generated from glycolysis
as long as you’re under aerobic conditions to make pyruvate then Krebs functions
Krebs relies on oxidative phosphorylation to recycle NADH and FADH2
what can Krebs alternatively run off of?
Krebs can break down fatty acids and proteins so if we do run out of sugar we can still make ATP by running off fats and proteins – not ideal but it will work
what kind of reaction is the ETC?
oxidative phosphorylation
how much ATP does ETC get us?
28-32 ATP
is the ETC dependent on oxygen?
must be aerobic because it needs O2
how do you stay in aerobic activity?
avoid intense situations and prolonged situations
these are moderate exercise so you don’t lose oxygen supply
why do we generate tension?
tension gets generated from CBC where the heads of myosin pull on actin so sarcomere shortens
we generate tension so that we can move what is called loads – when we’re talking about physiology, our body is the load!
what is required in order to create movement?
to create shortening of muscle and thereby moving your forearm up, you can ONLY accomplish that if we get the tension in the muscle to be bigger than the load
the tension doesn’t need to be 100 times bigger than the load, just like .2 bigger than the load and then you’ll see shortening – shortening is the only time you see movement
the load must be compensated for by tension: team biceps must create a bigger force than team forearm
can you generate tension but no movement?
you can generate tension and create CBC and not get the load to move
in tug a war, you could be pulling as hard as you can but it doesn’t mean the other team is going to move towards you
doing CBC doesn’t necessarily mean you get movement and shortening to happen – you can still have a contraction without having shortening and movement
contraction means you’re generating tension, but ONLY if you get tension to be bigger than the load you get shortening = movement
what is contraction?
contraction means you’re generating tension
but ONLY if you get tension to be bigger than the load you get shortening = movement
what are the three types of contraction types?
1) isometric
2) eccentric
3) isotonic contraction
what does “isometric” mean?
“iso” means the same and metric is about length = a contraction that keeps the same length
what happens during an isometric contraction?
this happens only when the load is *independent of the muscle
let’s say a bucket is sitting on a table and the individual reaches out to try and pull it up to their shoulder – so the weight of the load isn’t on the muscle until they start moving it, it’s on the table because the table is holding the load, not the muscle
the load is always bigger than the tension so we get no change in length/no shortening
tension < less than the load always
what’s the net result of an isometric contraction?
the load is too big so we get no change in length, no shortening because we don’t meet the criteria of the tension being bigger than the load = the load is always bigger than the tension but our load is being supported by something else other than the muscle we’re looking at
what are examples of isometric exercises?
pushing against walls because you’re never going to generate enough strength to make a wall move
if Bronson pushes against the podium she’s generating tension and doing CBC but she’s never going to get it to move
it’s like having a tug a war contest with an equal partner on the other side
what happens during an eccentric contraction?
same as isometric except in this case the load is dependent on the muscle
our individual standing there with the bucket added to their hand without a table underneath it; that muscle has to deal with the load of the muscle – the load is *dependent on the muscle, not supported by something else
instead of shortening of the contraction, you see lengthening happen in this contraction
tension < load but because load is on our muscle it’ll cause our muscle to go the opposite direction
what’s an example of an eccentric contraction?
put the textbook in your hand, your hand will drop because we have enough tension built up to support the forearm and hand but then we greatly increased the load
it’s like if you’re doing tug a war and suddenly a new individual jumps on the rope on the other side – you used to be still but because of the new person you get dragged the wrong way – instead of shortening of the contraction, you see lengthening happen in this contraction
what does isotonic contraction mean?
same tension
we maintain the tension
what happens during an isotonic contraction?
there’s no change in tension
to see shortening your tension has to be greater than the load – tension just needs to be a bit greater than the load and we’ll be able to move it
creating tension needs to use ATP so you don’t want to spend a lot of ATP so you use the exact amount that you need, you don’t generate extra tension – we only want to spend what we need to spend
how do we move our skeleton?
we move our skeleton primarily by isotonic contractions
what do you need to accomplish an isotonic contraction?
to accomplish an isotonic contraction we’re going to have to start off with an isometric contraction
if there’s a bucket sitting on the table, and you reach out to pick it up, you aren’t immediately going to see movement of the bucket
isometric has to happen first to build up tension necessary to get above the amount of the load so then you can do isotonic contraction – like in the tshirt example, you have to earn the $15 before you can move it out of the wallet to pay for the shirt
what kinds of contractions do weight lifters do?
weight lifters want to do an isotonic contraction to get the weight over their head but before they just grunt even though the weight isn’t going anywhere because they’re doing an isometric contraction to build up enough tension to get the load to be less than the tension so they can then do the isotonic contraction and get it to move
what happens as loads get bigger?
1) amount of time we spend in isometric contraction gets longer
2) speed/velocity in which we can accomplish the movement decreases
3) the response ability decreases
how does the amount of time in isometric contractions change in relation to load size?
the amount of time that we spend in isometric is going to be longer as the load gets bigger because we have to spend more time generating more tension to get bigger than the load
as we get bigger weights, the Arnold people spend more time grunting
the latency period ; the delay between when we start something and see the consequences of it(time in isometric contraction) is going to increase as the load increases
how does the velocity of movement change with increased load size?
the speed/velocity with which we can accomplish the move decreases
as the weights get heavier it takes them longer to accomplish the response and get the weight above their head
what happens to the response as load size increases?
being able to accomplish the task is going to go down as the weight goes up
as the load goes up, we lose the ability to be able to accomplish the response
you can maybe move the weight part of the way but you can’t get it all the way over your head because you ran out of ATP and don’t have enough CBC to get the tension you need
what’s the relationship between latency period and load size?
they’re directly dependent
what’s the relationship between twitch and movement?
to get this tension to happen, one twitch isn’t going to get us the tension that we need for whole muscle movements
however the tension from a twitch can be strung together with other twitches
this looks a lot like creating graded potentials, letting that cell go to rest and then creating another graded potential
same thing with the twitches, you get a twitch and then it goes away; if you hit it with another AP then you get another twitch
how do you maintain a contraction for a long period of time?
if you don’t let the cell go back to rest and don’t let myofiber go to rest and don’t let Ca get put away, you can sum the tension and build on the first level of tension
you’re not trying to reach a threshold potential, you’re just trying to build enough tension to get bigger than our load to create shortening and movement – you just need the AP to happen close enough together
this is how you maintain a contraction for a long time period
what’s tetanus?
when you maintain a contraction for longer than a single twitch
you do tetanus to get enough tension to move your body around from point A to point B or maintain seating position
you maintain a contraction for longer than a single twitch by not letting the myofiber go back to rest and not putting the Ca back to the SR so you can sum the tension and build up
what is the illness, tetanus?
the illness is when an organism triggers AP and is telling your muscles to contract when you don’t want them to
the common name for someone with tetanus is lockjaw because it’s one of the first muscles to succumb to this condition and gets frozen in place
this condition extends further and all muscles go into contracted position and the individual ends up in the fetal position
what are the two types of tetanus?
fused and unfused
what is unfused tetanus?
there is some relaxation happening
there’s some change in the Ca levels present, the Ca levels go up and then Ca levels in the cytosol go back down because we have some time to put it away before the next batch of Ca comes out of SR
not complete relaxation, we don’t go back down to 0 tension but we do see some decrease in tension happen
this is the more common of the two tetanus
what is fused tetanus?
no relaxation
the AP are hitting the muscle all the time, keeping the channels wide open so we can still be putting Ca in but more Ca is coming out of the SR reticulum than what’s going in so there’s high levels of Ca in the cell = high levels of tension
our legs and hand muscles often use fused tetanus
what are the two things that can vary with how our myofiber accomplished things?
1) how fast it accomplishes twitch
2) what’s providing ATP to the muscle
how can the speed of twitch vary between myofibers?
fast twitches build up tension a lot quicker and can be ended a lot quicker like sprinters in track whereas distance runners have slow twitch because that’s a longer time period
Apts. does our equation 1 that allows for break down of ATP so that your muscle can reach back out
your muscle reaches out at two different speeds: fast and slow twitch
what is fast vs. slow twitch?
our CBC is grab hold, pull, release, reach out, grab a hold, …
if our slow twitch is there, there’s a hitch in the system because you have to wait for the slow ATPase enzyme to do it’s job to reach out again
fast ATPase does its job quickly and there’s no hitch
what type of ATPase uses more ATP?
in the same amount of time, fast ATPase would use up more ATP since it would be able to catalyze more CBC
how does ATP generated vary?
different amounts of ATP are made by different processes which can be lumped into anaerobic vs. aerobic processes
aerobic processes give us more ATP
when we do things anaerobically glycolysis is the primary way to make ATP
what happens if a muscle is focused on being able to be successful anaerobically?
it’s going to be pushed more to make sure it can do glycolysis
we know glycolysis only gets us 2 ATP per glucose
glycolysis happens in the cytosol so we don’t need mitochondria so the number of mitochondria in a myofiber that functions anaerobically/glycolitically is going to be quite low
you also need lots of glycogen in these muscles because you only get 2 ATP per glucose so you need big amounts of glucose however, this creates an osmolarity problem
what happens if a muscle is focused on being able to be successful aerobically?
oxidative phosphorylation
we want as many mitochondria as possibly in the myofiber because there is where the ETC and Krebs cycle happen
what does a muscle need in order to function aerobically?
oxygen!
hello, oxidative phosphorylation
how do myofibers store oxygen?
1) what’s the problem?
2) how is it solved?
problem: we can’t load up myofibers with oxygen because they’d go out of the cell due to diffusion since it’s small and nonpolar and our plasma membrane isn’t a barrier to it
solution: however we can solve this problem by putting a bunch of oxygen on the outside OR bind it to something so that it’s too big to go out
solution: so you highly vascularize these myofibers to raise the level of oxygen outside but you also have a lot of myoglobin which binds to an oxygen once it gets in the cell and now the oxygen can’t leave the cell since myoglobin is too big to cross the plasma membrane
what are the characteristics that can vary in myofibers?
all myofibers do CBC and to do their pull they need ATP
what can vary is:
1) how their make their ATP (oxidative or glycolytically)
2) how fast they can accomplish CBC based on which ATPase is associated with their myosin to do equation 1 and get muscle to reach out
what are the 3 types of myofibers?
1) slow ATPase/slow oxidative
2) fast ATPase/fast oxidative
3) fast ATPase/ fast glycolytic
** you don’t see slow ATPase and glycolytic
what are the characteristics of a myofiber?
1) ATPase activity
2) speed of contraction
3) resistance to fatigue
4) number of enzymes for anaerobic glycolysis
5) mitochondria
6) capillaries
how does ATPase activity vary between myofibers?
do they run CBC activity really fast because they have quick enzyme or do they run it more slowly with a hitch in their CBC because they have the slow enzyme
how does speed of contraction vary between myofibers?
speed of contraction is what gives us the name for the activity
the fast ones can do a lot of pulls more quickly than the slow one can because the pulls and contractions happen based on the speed of the CBC
what is fatigue?
fatigue is when we run out of ATP
what resistance to fatigue do each of the type of myofibers have?
fast glycolytic loses ATP the most quickly and will fatigue the fastest
fast oxidative is in the middle
slow oxidative is slow to fatigue or doesn’t fatigue at all
when we want the myofibers to be doing stuff for us for a longer time we need more slow oxidative but if we want quicker contractions we would want fast glycolytic
what’s our best way of making ATP?
oxidative phosphorylation
glycolysis only gets us 2 ATP per glucose
what kind of resistance to fatigue is fast oxidative myofibers?
fast oxidative is our middle category
it’s using up ATP quickly but it’s also making ATP pretty similarly
but actually those amounts aren’t quite equal because making ATP is a little higher than our ability to use it so we do have a little bit of resistance to fatigue so we can hold and do activities longer but we’ll still run out of ATP
what kind of resistance to fatigue is fast glycolytic?
when you’re using up ATP really fast but you aren’t making it as fast
so it’s like having an expensive taste but only working at McDonalds which isn’t sustainable so you will fatigue quickly
how can the number of enzymes for anaerobic glycolysis change between types of myofibers?
glycolysis requires us to do 10 enzymatic steps – we can do more of this process but we need more enzymes present
if our myofibers is focusing on doing things oxidatively then we aren’t going to build up as many of those because we’re planning on having lots of oxygen around and not having to do a lot of things anaerobically
how many enzymes for anaerobic glycolysis does each type of myofiber have?
fast oxidative-glycolytic can sometimes run out of ATP and have to rely on glycolytic so that’s why it’s intermediate fatigue
fast glycolytic focus is on glycolysis; it’ll make ATP when it can with oxidative phosphorylation but it plans on running anaerobically for the most part so it needs a ton of glycolytic enzymes available to compensate for the fact that only 2 ATP come out of each glucose
how does the number of mitochondria between types of myofibers vary?
mitochondria are the location of Krebs cycle and ETC
when you’re focusing on oxidative, you need tons of mitochondria
if you’re going to focus on anaerobic then you don’t need that much mitochondria and you don’t need to spend energy building them if you don’t have oxygen to power them
how does the number of capillaries between the different types of myofibers vary?
capillaries provide blood supply which carries oxygen
they can flood the outside of the cell with oxygen to solve the oxygen gradient problem since we can’t store oxygen in our myofiber
you don’t need as many capillaries around fast glycolytic myofibers
what is myoglobin?
our second solution to oxygen not being able to be stored is that we can keep it in the cell if we bind it to something that’s too big to cross the PM aka myoglobin
which types of myofibers have high myoglobin content?
myoglobin content is very high in cells where we want to store oxygen so we don’t run out of it like slow oxidative and fast oxidative
not worried about oxygen for our fast glycolytic so very low myoglobin levels
what causes light or dark coloration of myofibers?
fibers that are dark because they have high myoglobin content
the myofibers that are very light have low myoglobin content
at KFC you order light or dark meat- higher myoglobin content is dark meat or lower in myoglobin content which is white meat
where is dark or light meat found in the body?
we get far more red/dark coloration to the myofibers that have a higher myoglobin content that are oxidative than the ones that are glycolytic that are white/fast glycolytic
breast meat in a chicken is fast glycolytic muscle whereas drumsticks and thighs are fast oxidative/slow oxidative category
how much glucose is in fast glycolytic cells?
fast glycolytic cells are packed with straight up glucose you create an osmolarity problem
glycogen solves that by chaining together glucose molecules to lower osmolarity
how much glycogen is there in the different types of myofibers?
if glycogen content is low then we’re being very efficient in slow oxidative
middle glycogen amount for fast oxidative
high glycogen amounts for fast glycolytic
what are the tradeoffs in CBC?
doing CBC gets us our pull
we have a tradeoff between speed with which we are able to pull vs. how long we can sustain the pull
different myofibers have different amounts of each
what types of myofibers are in muscles?
muscles don’t have to be an equal proportion of the different types
it’s usually a push towards slow oxidative or towards fast glycolytic depending on in that tradeoff which one is necessary
do we need more quick activity where we’re willing to give up endurance of that muscle or do we need endurance and we’re willing to give up how much tension we can create?
what kind of myofiber is in a chicken’s legs?
the majority of the day a chicken is walking around because it needs endurance for its legs
it’s not about quick bursts of movement, it’s about consistently being able to maintain movement so you see more slow oxidative aka more dark meat
what kind of myofiber is in chicken breast?
flight muscles in chickens aka the breast meat, chickens can’t sustain flight they just pop up a little to get to a higher perch but they aren’t going to fly south to the winter
they just need big bursts of short energy aka fast glycolytic
how does a duck breast myofiber compare to chicken breast? why?
ducks sustain flight
so duck breast meat should be a lot darker than a chicken
if you made KFD, you wouldn’t really be able to have white or dark meat because the white meat is a lot darker in a duck because they have sustained light and need more slow oxidative/fast oxidative component to their breast meat/flight muscles
what genetic dispositions do we have in terms of myofiber types?
there’s a genetic basis for the starting percentages for our various muscles
we can think of this genetic basis as species level, there’s also differences within humans
our legs are more red meat than our upper body because we do less with our upper body
we also know some people are better springs vs. distance runners
can myofiber types be changed?
• Genetic basis is in play based on DNA that parents gave you but you can also modify it
you can take anyone in the room and improve their marathon time or take someone who’s a bad sprinter and modify their 50 yard dash time
however you can’t modify to a huge extent, there are limits
you can’t take Hussain Bolt and turn him into the marathon winner
how can you modify myofibers to basically have them switch categories?
how can you take a slow oxidative and turn it into a fast glycolytic?
It’s just about how we’re making ATP and which enzyme we have present
the instruction for both of these things are in the DNA so we can just change how the instructions are read
to do the modification you might be changing structures present
what are the structural changes that can be made in myofibers?
1) if you want more pull you need more CBC – to get more CBC you need more myosin and actin so you need more sarcomeres – if you put more proteins in there you can get more pull
2) what if you want to be more aerobic? you need to increase the number of capillaries and mitochondria
what are functional changes that can be made to myofibers?
if you have mitochondria present, you can rely more on them rather than glycolytic components by focusing more on oxidative side rather than glycolytic
what if you are forcing on fast glycolytic activities?
if you’re going to focus on glycolytic, you shouldn’t spend on mitochondria, you would just spend on maintaining mitochondria and capillaries – it’s an energy tradeoff
we’re playing with the tradeoff; we have limited energy
why doesn’t your body maintain big muscles if they aren’t in use? what is disuse?
we know we need the muscle to move our forearm to our shoulder.
If you don’t do much in term of loads, then you don’t need a bigger bicep; you just need enough tension to overcome the load
so there’s no point in maintaining a giant bicep because it’s a waste of energy
disuse is when you don’t use the muscles, you don’t need to generate the tension so why maintain the muscle and the energy that it needs to maintain it? Instead break the muscle down and use the energy in another place
what is atrophy?
when we have disuse or muscle disease situations you see atrophy of the muscle = muscle getting smaller
when you get a cast off, your muscle has gotten a lot smaller because there was no point in investing in it because it wasn’t doing its work so the muscle atrophied
you’re taking money that was being spent on the muscle and putting it somewhere else in the body
what is hypertrophy?
if we use muscles more and put bigger loads on them and stress them more, then the muscle increases in size because we add to it so that the muscle can do its job better = hypertrophy
Arnold Classic is about hypertrophy of the muscles, making them bigger than they were before
how do you accomplish hypertrophy?
You should be doing moderate activity to keep us in the aerobic range and be doing aerobic exercise
how can you get your muscles to do more?
to change structure and function of our muscles, to be able to do more, your circulatory system around these muscles changes and increases the vascularization
your circulatory system is highly adjustable and make new paths or take away paths
with aerobic exercise you change vascularization and increase it to muscles that are working aerobically
how does aerobic activity work? what’s the point of it?
aerobic activity is dependent on number of mitochondria
as we’re feeding oxidative phosphorylation that happens in our mitochondria so we see the number of mitochondria in those muscles that you’re doing aerobic exercise go up
the whole point of this is that the fatigue amount goes down
what happens with continued aerobic exercise?
when you start aerobic exercise you do fatigue and it sucks but if you keep doing it then it gets easier
but once you meet that level and the exercise doesn’t make you fatigue, the driving power is gone and you’re not going to keep changing
you have to keep stepping up aerobic activity to keep changing but if you want to maintain your current body then just stay at the same level
what kind of exercise is weight lifting? why?
anaerobic exercise
you need as much tension as possible to move the weight and for a short period of time and that’s it
focuses on glycolysis
how does anaerobic exercise work?
you want as much tension generated as possible - you want as many myosins pulling as many actins as possible
muscle gets bigger because you’re adding sarcomeres, you’re adding myofilaments which takes up more space - more sarcomeres means more CBC
the number of enzymes with glycolysis increase because you’re focusing on doing things quick, fast, short, and not really needing oxygen because you’re relying on quick process
what kind of activity should you do if you want to be big and bulky? what if you just want to maintain your current tone?
if you want to be big and bulky, do anaerobic exercise
but if you just want to sustain muscles and get them better working, increase them a little in size, focus on aerobic activity
what are motor commands?
telling those motor neurons what to do comes from motor cortex in our cerebral cortex
it’s right next to our somatosensory cortex
where is your motor cortex located?
in the cerebral cortex right next to the somatosensory cortex
makes sense because we get information that tells us we need to move towards or away from something and right next to that area where we can direct those movements
does the motor cortex have an homunculus?
there’s a second homunculus (second spatial map, distorted image) happening in motor cortex
it’s distorted in different ways because it’s about the number of motor units in a certain area rather than the number of receptors in a particular area so you get a slightly different homunculus from the motor cortex vs. somatosensory cortex but both give a distorted picture
what does voluntary movement mimic?
voluntary movement is happening from motor cortex but really it mimics and matches what happens with the reflexes that the doctor checks in the office
so if you know how you’re basic reflexes work then you can expand that and understand how you do general body movement
can skeletal muscles be stimulated and inhibited?
skeletal muscles can only be stimulated
happens as a result of our CBC pulling – you can’t push the rope back the other way; the myosin doesn’t push the actin the other way, all it can do is grab on to actin and pull it
if your skeletal muscles can’t be inhibited, how do you get a muscle to go in the opposite direction?
muscles can only be stimulated by themselves and can only cause a shortening/pull in one direction so you need another muscle to cause a shortening/pull in the other direction
when you talk about your bicep moving your forearm to your shoulder, your triceps gets it to go back down – your muscles must work in pairs so you can move particular joints in two directions – you can make the joint angle be smaller or larger
what are the net results of aerobic activity?
increased vascularization, increased number of mitochondria and decrease in fatigue
what are the net results of anaerobic exercise?
increase in myofiber diameter because of increased sarcomeres and increased glycolytic enzymes
what does aerobic and anaerobic activity help with?
it helps to reach hypertrophy
what are the two categories of muscles in terms of movement?
when you pull the head and made the head angle in myosin smaller, that’s called flexing - your bicep is causing a flexing motion so it’s the flexor
whereas your triceps is making the angle bigger, it’s extending the angle so it’s called the extensor
what kind of system is your proprioception system?
afferent system that’s a part of your somatosensory system
it gives information about the position of bones and muscles
how does the proprioception system work?
it gives information about the position of bones and muscles
it does this by having receptors associated with our muscles and tendons that connect muscles and bones
it provides information through mechanoreceptors, stretch receptors, that tell us how much load is on a particular muscle and it sends that information to our brain which develops a sort of chart that says; okay, when my arm is in this position, the various loads that I am getting information wise from all my muscles and tendons matches up to this line and tells me that my arm is in this position and my arm is facing down – it would give different information if your hand was facing up
what do the muscle spindle and goggle tendon do?
muscle spindle detects the stretch of the middle of your muscle and tells you how your body is positions so part of your proprioception system
golgi tendon tells you the stretch of your tendon and is also a part of your proprioception system
this is how you know if your hand got moved by someone else even though your brain wasn’t sending signals for your hand to move - it’s a combination of information from the two
what are golgi tendon organs?
connection between muscles and bones
the officer says close your eyes and touch your nose it works fine because of proprioception system is giving that information to the brain and the brain is correctly processing it
you have receptors in the middle spindle of our muscles to tell how much contraction/force is being generated by the muscle at that point in time – however this is not sufficient because someone could take my arm and move my arm behind me – I’ll still feel that my arm is in that position even though my muscles are relaxed but you’ll feel and know you’re in that position because of the information coming from the tendons (our connection between muscles and bones) = golgi tendon organs
what is a reflex?
better term is spinal reflex because that’s where information is being processed
it’s getting an “involuntary contraction to happen in our skeletal muscle
it’s still our skeletal muscle but the message telling our muscle what to do is coming from the spine and not the motor cortex
how do muscle pairs work?
afferent to interneuron to efferent to get a response but it goes through the spine to get a faster response than going all the way to the motor cortex
if you want to inhibit a muscle you can hyperpolarize motor neuron of its counterpart
you can’t relax the skeletal muscle itself but we can stop telling it to do things
we can’t inhibit the flexor itself but we can inhibit the motor neuron that’s running the flexor and therefore cause it to stop contracting and effectively inhibiting it
you CAN inhibit motor neuron but CAN’T inhibit the skeletal muscle itself
how does the knee jerk work?
stimulating extensor and inhibiting motor neuron of flexor when your knee kicks out
the doctor is hitting your patellar ligament (often called tendon) which is creating a stretch there that’s pulling on the kneecap but the other side of your kneecap is connected to your quad muscle so it’s getting pulling; it’s not contracting, it’s getting pulled
when it does this it goes through proprioception system to send the information to the brain – however it has to go through the spinal cord, thalamus and then gets to cerebral cortex
the spine can look at the information and sees how much stretch is happening on the quad; if it’s a little then no big deal; if it’s a lot then it goes we have a dangerous situation and could lose the knee so we need to respond faster than waiting for the motor cortex
you need to reach a threshold/level of stretch that need to be realized as dangerous and we need to response – in that situation we want to contract the extensor (the quad) so we stiffen the knee joint and make it harder to push it in the wrong direction
what’s the flexor and extensor in your arm?
flexor = bicep
extensory = tricep
what’s the flexor and extensor in your leg?
extensor = quad
flexor = hamstring
what’s the myosin-ATPase activity for the types of myofibers?
slow-oxidative: low
fast-oxidative: high
fast-glycolytic: high
what’s the speed of contraction for the types of myofibers?
slow-oxidative: slow
fast-oxidative: fast
fast-glycolytic: fast
what’s the resistance to fatigue for the types of myofibers?
slow-oxidative: high
fast-oxidative: intermediate
fast-glycolytic: low
what’s the oxidative phosphorylation capacity for the types of myofibers?
slow-oxidative: high
fast-oxidative: high
fast-glycolytic: low
what’s the enzymes for anaerobic capacity for the types of myofibers?
slow-oxidative: low
fast-oxidative: intermediate
fast-glycolytic: high
what’s the number of mitochondria for the types of myofibers?
slow-oxidative: many
fast-oxidative: many
fast-glycolytic: few
what’s the number of capillaries for the types of myofibers?
slow-oxidative: many
fast-oxidative: many
fast-glycolytic: few
what’s the color for the types of myofibers?
slow-oxidative: red
fast-oxidative: red
fast-glycolytic: red
what’s the glycogen content for the types of myofibers?
slow-oxidative: low
fast-oxidative: intermediate
fast-glycolytic: high
