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What are the contraction: "passive" portions? (3)
- 1. action potential initiation: acetylcholine binds, sodium FLOWS into the cell
- 2. calcium release from SR: AP reaches SR, calcium FLOWS out of SR
- 3. first powerstroke: calcium binds to troponin, myosin head binds actin, 1st powerstroke initiated
what are the contraction: "active" portions?
- 1. contraction continuation: ATP needed to release myosin head, to generate "ratcheting" if calcium still present (remember: calcium need to be present bec without calcium, we won't have myosin binding site exposed)
- 2. contraction termination: ATP needed to pump calcium back into SR
- 3. contraction preparation: ATP needed to pump sodium out of cell
we want to generate the gradient... most ATP used in ratchet but need ATP to maintain gradient
how do muscles use ATP for energy? (3)
- 1. simple: ATP --> ADP + P + energy
- 2. super simple: APPP --> APP + P + energy
- 3. complex: ATP + H2O --> ADP + P + H + energy
- - so muscles use ATP for energy through hydrolysis
- - splitting by using water... break using water...
- - use water in cytoplasm to break ATP
how much ATP is used by a small active muscle?
about 187 quadrillion ATP per second
what are sources of ATP?
- ATP stores... to regenerate ATP from ADP
- need to find ways to stick Pi back to ADP and make more ATP
- we basically put energy in the bonds when you make the molecule
- we break the bonds to release energy and use it in any process we transfer ATP to
- 1. stored ATP (0-3 seconds)
- 2. regenerate ATP from ADP:
- a. phosphagen system (PS) 3-15s
- b. an-erobic glycolyis (AnG) 15-60s
- c. aerobic glycolysis/lypolysis (AGL) 60+s
1st source of ATP: ATP stores 0-3 s
- simplest/quickest way to get ATP
- while resting: fatty acids being used in muscle to create ATP stores... not glucose because being used up in another system, so use a slow method to make ATP, we have time because we're resting
- while exercising: ATP stores last for about 3 seconds (ex for a 25 meter dash)
- it's a NINJA energy source... for quick movement
- why not store more ATP? high ATP triggers apoptosis (cell death)
2nd source of ATP: phosphagen system 3-15s
- simple/quick way to replenish ADP --> ATP
- while resting: already created max ATP stores? now create alternative source of phosphate groups... ATP + creatine --> ADP + creatine-P... sotres ~8x more creatine-P than ATP
- while exercising: already used up ATP stores? now use alternate source of phosphate groups!!!! ADP + creatine-P --> ATP + creatine (opposite rxn of while in resting)
- creatine phosphate main ATP source for ~15 seconds
- ex for weight lifters or for 100 meter dash (good for high, energetic, short performance
- basically create creatine phosphate... new source for phosphate groups
how does creatine help generate ATP the quick way?
- creatine is made mainly in the LIVER from diet
- then goes to BLOOD
- then goes to MUSCLE
- in muscle creatine kinase moves phosphate ion to and from creatine
how does creatine indicate renal function?
- creatine is used clinically to determine kidney function
- we see that some creatine-phosphate is converted to creatine that goes to blood
- this is then filtered in kidneys and released in urine
- if kidneys aren't functioning properly, creatine levels are high in serum (blood)
- this is because the kidneys aren't clearing it out
3rd source of ATP: anaerobic glycolysis 15-60s
- somewhat simple or quick way
- while resting: glucose is converted to glycogen (glycogen = a string of glucose)
- while exercising: after ATP stores and creatine-P are used up...
- glycogen --> glucose --> pyruvate + 2ATP --> lactate
- ATP --> ADP + P + energy
- anaerobic glycolysis is the main ATP source for ~60s
- perfect for a 200-400 meter dash
can you feel the burn??? where does the burn from exercise come from???
- does not come from lactic acid!!!
- it's the hydrogen ion that's released during ATP hydrolysis
- when H+ goes into circulation, we feel the burn
- lactic acid is just a small part of it
4th source of ATP: aerobic glycolysis and lipolysis
- complex or slow way to replenish ADP --> ATP
- basically more complex and slower but produces a lot of energy!!!
- main source of ATP after 60 seconds
- good for a 26.2 mile dash
- while resting:
- (1) glucose --> (muscle/liver) --> glycogen
- (2) fatty acids + glycerol --> (adipose) --> triglyceride
- notice, not just glycogen in muscle but also in liver
- while exercising:
- (1) glycogen --> glucose --> pyruvate + mito + O2 --> 34-36ATP!!!
- (2) triglycerides --> fatty acids + mito + O2 --> 34-36ATP!!!
- notice difference from ANA... instead of using pyruvate with 2 ATP, bring pyruvate into mitochondria and make a lot more ATP
hourly breakdown of aerobic glycolysis and lipolysis: what happens at the 1st hour, after 1 hour, and after 3 hours???
- FIRST HOUR: muscle glucose
- major: glucose from muscle glycogen
- minor: glucose from liver glycogen
- minor: fatty acids from lipid cells
- AFTER 1 HOUR: liver glucose and fats
- minor: glucose from muscle glycogen
- major: glucose from liver glycogen
- major: fatty acids from lipid cells
- AFTER 3 HOURS: lots fr lipids, med from liver glucose
- minor: glucose from muscle glycogen
- medium: glucose from liver glycogen
- major: fatty acids from lipid cells
- "HITTING THE WALL"
- depletion of muscle glycogen!!!
- without that, have to rely on energy demand from BLOOD sources
- slower to get the energy so you get exhausted
why do we get immediate muscle pain?
because of partial or full tear of muscle/tendon/ligament
delayed onset muscle soreness (DOMS)
- peaks around 2-3 days after the event
- NOT due to the lack of lactate or acidity
- most likely due to tears in muscle cells or connective tissue
- stimulates prostaglandins and causes inflammation and pain
what is the optimal rest between exercises? why?
- 48 HOURS
- highest levels of muscle growth factors
- highest gains in muscle strengths
- not efficient to exercise everyday to stimulate muscle growth... for deposition of protein
- unless your goal is to reduce calories... then it's okay to do everyday
FAST TWITCH (IIb) vs SLOW TWITCH (I) muscles???
- - we see different levels of muscle types for different runners
- FAST TWITCH
- - chicken breast = flying need pectoral muscles to generate that forms
- - chickens don't really fly
- - A LOT of force generated then gone (fast)
- - for power and fitness
- - why is it white? use ATP source and creatine phosphate
- - use phosphagen system and ANA system so no need for O2
- - so there's no capillaries, blood or mitochondria
- SLOW TWITCH
- - slow twitch more for endurance and stamina
- - use aerobic method - have time to make ATP while walking around
- - why red? because we use a lot of O2, need a lot of blood vessels, mito, capillaries and hemoglobin
ADAPTATION: what happens during continual activity or training and also during continual INactivity and NON training
- continual activity/training: muscle changes!!!
- 1. POWER (anaerobic) - for a sprinter
- - fast twitch <-- intermediate fibers (intermediate fibers are converted to fast twitch muscle fibers)
- - more glycogen reserves
- - hypertrophy, more myofibrils (hypertrophy = muscles get larger... that's why sprinters have big muscles... lots of glycogen reserves in muscles)
- 2. ENDURANCE (aerobic) - for marathon runner
- - fast twitch --> intermediate fibers (just a little bit of fiber switching)
- - increased mito, capillaries and RBCs
- - more efficient at ATP production from mito
- continual inactivity/non-training
- - reversal of above
- - get atrophy and loss of adaptations
- - if you don't use it, won't maintain it... won't put energy to maintain it
- - caused by illness, injury and other commitments like studying or laziness
power vs strength vs endurance???
- power: short use, anaerobic, sprinter, big weights, fast twitch (IIb)
- strength: mix use, an/aerobic, interval running, small weights
- endurance: constant use, aerobic, marathoner, "aerobics," slow twitch (I)
what's most effective for weight loss? for cross training? for interval training? STRENGTH
biochemical ERGOGENIC aids
- systemic substances that enhance competitive performance
- so many ineffective non pharmacy substances, except one... CAFFEINE!
- so many pharmacy related substances... which ones are effective? what's on the prohibited list is most likely effective!
- sooooo.... caffeine is an effective ergogenic drug that increases epinephrine and focus your stamina
#1 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- anabolic androgenic steroidsa. testosterone and related substances
- - stimulates protein synthesis to increase muscle growth
- - stimulates hematopoiesis to increase RBC production
- b. Rx uses
- - patients with atrophy due to illness or injury (bec it helps them back on their feet)
- - patients with anemia (stimulates receptors)
- - patients with hooves
- c. Side effects: altered moods, acne, alopecia, genital shrinkage
#2 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- peptide hormones + growth factors
- - ergogenic aid: cell growth and proliferation
- - examples:
- growth hormone
- chorionic gonadotropin + luteinizing hormone (only in females!)
- EPO + EPO stimulators
#3 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- Beta-2 agonist
- - ergogenic aid: bronchodilation
- - examples: albuterol, salmeterol
#4 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- estrogen receptor modulators
- - ergogenic aid: counter side effects of anabolic steroids
- - examples: tamoxifen (for breast cancer) & clomiphene (for polysystic ovarian cancer)
#5 prohibited drugs in international competition: 2010 prohibited substance list (in/out)
- diuretics or plasma expanders
- ergogenic aid: masks drug use, weight loss
- diuretic examples: furosemide, spironolactone
- expander examples: dextran, mannitol
- diuretic = decreases amount of fluid in system, pee a lot
- plasma expander = increases the amount of fluid in system
- basically used for the same purpose... to dilute effect of substance in your system, to mask drug use by peeing it out or diluting it
#1 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- ergogenic aid: increase endurance, focus, stamina
- examples: amphetamine, methylphenidate, ephedrine
- commonly ADHD medications
#2 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- ergogenic aid: suppress pain
- examples: oxycodone, fentanyl, morphine
- suppresses pain during competition to last longer
#3 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- ergogenic aid: suppress inflammation + pain
- examples: prednisone, dexamethasone, cortisol
#4 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- ergogenic aid: suppress emesis (vomiting) + pain
- examples: tetrahydrocannabinol
#5 prohibited drugs in international competition: 2010 prohibited substance list (in only!!!)
- beta blockers
- ergogenic aid: increases stability
- examples: atenolol, bisoprolol, metoprolol, propanolol
- prohibited for specific sports (18 total)
- basically decreases shaking from nervousness and good for sports where stability is impt
2004 international journal of sports medicine... analyzed 634 supplements from 215 global suppliers... laboratory accredited by international olympic committee... results???
- you can take substances and not know it!!!
- 0% stated any hormones or pro hormones as ingredients
- 15% tested positive... most had testosterone pro-hormones
- 10% tested 'murky'
- smart marketing.... don't promote that it has the products
- say it enhances but doesn't say it has prohibited substances in it
- term for age-related loss of muscle mass, strength and function
- 30-50% decrease in an/aerobic performance
- mostly due to atrophy of type IIa fibers
- also associated with decrease in:
- myoglobin (transports O2 in muscles)
- satellite cells (muscle stem cells, in injury situations, might need to make more muscles)