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Anatomy Unit 16
| Question | Answer |
|---|---|
| Tendon | - at the end of muscle fibers - attach the muscle to the bone |
| Fascia | - dense connective tissue covering entire muscle - Fascia is a continuation of the tendon |
| myofibrils | - smallest unit - contractile fibers within muscle cells - play a fundamental role in the muscle contraction mechanism |
| Muscle fibers | several myofibrils bundled together |
| Fascicles | - several muscle fibers bundled together - every muscle in the body is made of several fascicles bundled together |
| Epimysium | - most superficial layer of connective tissue - surrounds all of the fascicles (or entire muscle) - located under fascia |
| Perimysium | - middle layer of connective tissue - surrounds each fascicle (or several muscle fibers) |
| Endomysium | - deepest layer of connective tissue - surround each muscles fiber (or several myofibrils) |
| layers of connective tissue | epimysium, perimysium, endomysium |
| The various bundles of muscle | myofibrils, muscle fibers, fascicles |
| muscle cells = | muscle fibers |
| muscle cells background | - muscles are made of cells - the muscle fibers section of a muscle are the cells - one of the 260 types of specialized cells - same properties as cells |
| Components of muscle fibers (cells) | Sarcolemma, sarcoplasmic reticulum, myofibrils, sarcoplasm, nuclei, mitochondria |
| Sarcolemma | cell membrane surrounding several myofibrils |
| Sarcoplasmic reticulum | - membranous network of channels and tubules with muscles fiber - houses calcium |
| Myofibrils in cells | contractile units |
| Sarcoplasm | another term for cytoplasm inside muscle cells |
| Nuclei | more than one in each cell |
| Mitochondria | - muscles have a lot of mitochondria - need to make ATP |
| Sarcomeres | - structural and functional unit of a myofibril, where the contraction actually happens - myofibrils are actually sarcomeres joined end to end |
| Muscle tissue is | contractile: can shorten and thicken |
| You are born with | every muscle fiber you will ever have |
| 3 different types of muscle tissue | Skeletal, smooth, cardiac |
| Skeletal Muscle tissue | functions: - move the body - voluntary Characteristics: - striated (Marked with parallel lines) |
| Smooth muscle tissue | functions - contract internal organs of body - involuntary Characteristics: - lack striations (why its smooth) |
| Cardiac muscle tissue | functions: - contract heart - involuntary characteristics: - striated |
| Z-lines | - at both ends of a sarcomere - extend from from z-line to next z-line |
| Thin (actin) filaments | - held by direct attachments to z-lines - actin = protein that makes up this filament - consists of double strands of actin twisted in a helix |
| thick (myosin) filaments | - not attached to z-lines - myosin = protein that makes up this filament - consists of long myosin molecules |
| Structures on thin filaments | troponin = small structures attached to actin - troponin loves calcium Active binding site = located on each actin molecule tropomyosin = long "wires" that wrap around actin - cover up active binding sites |
| Structures on the thick filament | - each thick filament consists of protein strands called cross-bridges (heads) that project outward - these cross bridges move back and forth |
| Neuromuscular junction | - nerves are connected to a skeletal muscle - nerves communicate to muscle when to contract - when the brain wants a movement to happen, a signal (nerve impulse) is sent down the nerve to the muscle |
| Neuromuscular junction after nerve impulse is sent | - once impulse reached axon terminal, a neurotransmitter is released from end of nerves to signal muscle to contract - neurotransmitters are released to synaptic cleft - neurotransmitter = acetylcholine - response = muscle impulse |
| The sliding filament theory | the process that occurs then in the muscle in order to shorten it and produce a movement |
| What is the purpose of muscles? | the job of muscles are to pull on bones and cause movement - muscles pull one bone towards another bone, they never push - muscles need to shorten |
| Where sarcomeres come into play | if thousands of sarcomeres shorten in a muscle, then the entire muscle will shorten and produce movement |
| What is the sliding filament theory? | - sarcomeres shorten when thick and thin filaments slide past each other, bringing z-lines closer together without changing filament length - repeated shortening of many sarcomeres leads to overall muscle contraction (muscle shortens) |
| Sarcoplasmic reticulum physiology | - high concentration of calcium ions - in response to muscle impulse, it becomes permeable to calcium ions |
| Troponin and tropomyosin physiology | - at rest troponin - tropomyosin blocks myosin binding sites on actin - calcium binds to troponin, causing a shape change - this shifts tropomyosin exposing actin's binding sites for myosin |
| Shortening of sarcomere | - myosin cross-bridge heads attach to binding sites on actin - they pull the actin filament bringing z-lines closer together - the heads release, reattach further along, and repeat - shortening the sarcomere |
| ATP | - you use ATP whenever you do any muscle contractions - this breakdown of ATP to ADP releases energy into the body - this energy provides the force needed for a muscle contraction |
| Role of ATP in muscles contractions | - cross-bridge pulls on actin, then ATP binds causing it to detach - ATP is broken down to ADP + phosphate, releasing energy - this energy resets "cocks" the cross-bridge so it can attach and pull again (cycle) |
| Rigor Mortis | - 3-4hrs after death, calcium leaks from the sarcoplasmic reticulum exposing active binding sites allowing cross-bridges to form - without ATP, cross-bridges cannot detach, causing sustained muscle contraction - as calcium breaks down , stiffness fades |
| Muscle relaxation | - ACH decomposes by enzyme (acetylcholinesterase) - calcium goes back to sarcoplasmic reticulum - tropomyosin covers up binding site |
| Zoom in a Hot mustang | Zones, bands, and lines - when looking at a sarcomere, the sarcomere is split up into sections (anatomy) |
| Z-line anatomy | where two sarcomeres join each other |
| I band anatomy | only actin filaments |
| A band anatomy | length of the myosin filaments (area that contains all the proteins) |
| H zone anatomy | only myosin filaments |
| M-line anatomy | center of myosin (anchors myosin in place) |
| Physiology - muscle sarcomere contraction | when the muscle contracts |
| Z-lines contraction | come closer together |
| I bands contraction | shrinks |
| A-band contraction | stays the same |
| H-zone contraction | shrinks |
| M-lines contraction | no physiology |
| Cellular respiration cycle types | Glycolysis Kreb's Cycle Electron Transport Chain |
| How does oxygen get to the muscle | - blood carries oxygen in body from lungs to body cells - oxygen is transported on red blood cells bound to hemoglobin |
| Myoglobin | - blood released the oxygen form hemoglobin into muscle - in muscles, oxygen attaches to myoglobin, found in muscles cells (reserve amount of oxygen) - gives muscle color (pigment) - reddish/brown - myoglobin can store oxygen in muscle tissue |
| Oxygen supply, can we supply enough? | - Doing heavy work, body usually supplies enough oxygen - start working muscles a lot, not enough oxygen is there to keep Krebs and electron transport chain |
| Lactic Acid | - switch back over to glycolysis (anaerobic) - byproduct of glycolysis - shift back to anaerobic means = lactic acid threshold |
| Oxygen Debt Development | - the liver gets rid of lactid acid. However, this needs ATP too - not enough ATP to go around - result = build up of lactic acid - thus, person develops an oxygen debt |
| Oxygen debt definition | - the amount of oxygen needed to make enough ATP to get the body back to normal |
| Muscle Fatigue | - when a muscle loses its ability to contract due to it being overworked - number of causes - most likely due to a rise in lactic acid accumulation in muscle |
| What does not cause muscle soreness | Lactic acid |
| Exercise training | - more efficient body at anaerobic/aerobic processes - people who train don't produce as much lactic acid - more oxygen to the muscle - more mitochondria = more ATP |
| ATP energy | - carries energy in our bodies from 260 different types of cells - each ATP has adonosine molecule attached to 3 phosphates in a chain - 2nd + 3rd phosphate = high energy bond (release energy when bond is broken) |
| ATP -> ADP -> ATP | - once an ATP loses the phosphate it becomes ADP )adenosine DIphosphate) - phosphorylation = process of ADP gaining another phosphate to become ATP - Creatine phosphate = donates P to ADP to make ATP (causes phosphorylation) |
| Cellular Respiration Definition | process that releases energy from food and makes it available for the human body to use in the form of ATP |
| Cellular Respiration | occurs in 3 distinct, yet interconnected reactions - Glycolysis - Kreb's cycle - Electron transport chain Some occurs in cytoplasm, others in mitochondria |
| 90 second rule | - Anaerobic respiration (glycolysis) takes place at the onset of exercise for up to 90 seconds - After that, the body relies on aerobic pathways (Krebs cycle and Electron Transport Chain) |
| Aerobic vs Anaerobic | Anaerobic = no oxygen - glycolysis Aerobic Reactions - oxygen = required - if oxygen is available, more ATP can be made from other two systems - Krebs Cycle and Electron transport chain (both work in mitochondira) |
| Glycolysis | - getting energy from food - occurs in cytoplasm - breaks down glucose easily - gives you 2 net ATP - happens REALLY fast - Anaerobic |
| Krebs Cycle | - Aerobic pathway (needs oxygen to work) - occurs in mitochondira - gives you two ATP |
| Electron Transport chain | Aerobic pathway Occurs in mitochondria Makes 32-34 ATP |
| Total ATP for glucose molecule | 38 ATP |
| Fat | - 129 ATP - your body switches over to fat once you've been working out for about 3 min, and increases fat usage with more time |
| Exercise cycle point | you should work out continuously for at least 10 min if you want to lose fat |
| Threshold stimulus | - when muscle is stimulated to contract, muscle has to reach a certain threshold - once threshold is reached, muscle fiber contract and all sarcomeres contract - all or nothing |
| Length of muscle fiber and force | - length stretched affects amount of force produced - stretched beyond, force decreases - myosin cross-bridges cannot reach binding sites - short length fibers cannot shorten |
| Contractions | - contribution of multiple muscle fibers (sarcomeres) in muscle, force depends on - frequency individual muscle fibers are stimulated to contract - how many fibers take part in overall contraction |
| Levels of contraction | Twitch Summation Tetanus |
| Twitch | - Contraction of single muscle fiber - regular muscle movement |
| Summation | series of twitches which the muscle never really relaxes - twitches combine and thus a sustained contraction occurs - more force is generated |
| Tetanus | - to the point where there is NO relaxation, not even partial relaxation - highest possible force generated |
| Motor units | - multiple muscle fibers put together - few motor units = precise movements - more motor movements = larger muscles - muscle is composed of many motor units - muscle fiber + unit = stimulated at same time |
| Recruitment | - increase in the number of motor units activated for a movement - with light movements, only a few motor units are recruited and contract - with strenuous or heavy movements, more motor units are recruited |
| We never use 100% of our muscle fibers | - regular movements use 1/3 muscle fibers - heavier things are 50-60% - all of muscle fibers would be used in superhuman examples - causes muscle bleeding |
| Types of contractions | Isotonic contraction - Concentric contraction - eccentric contraction Isometric contractions |
| Isotonic contraction | when a muscle changes its length |
| Concentric contraction | muscles shortening when they contract |
| eccentric contraction | - muscle is also contracting while it's lengthening - cross-bridges are working |
| Isometric contractions | a muscle can contract and there can be no change In length |
| Fast twitch and slow twitch muscles | - muscles vary in contraction speed, ATP production, etc. - Slow twitch - fast twitch type lla - fast twitch type llb muscles in body vary as to which one they have, or combo |
| Slow-twitch | - red (lot of oxygen) - aerobic - do not fatigue easy - many mitochondria - lots of ATP |
| Fast-Twitch lla | - white - in between other two, intermediate fiber - fatigue not as easy as llb, easier than slow-twitch - more oxygen capacity than llb |
| Fast-twitch llb | -white -anaerobic - fewer mitochondria - fatigue easy (lactic acid accumulation) - larger muscles (more explosive force produced) |
| How do you build muscle | - when you work out you tear your muscle - body goes back to repair it and build It back stronger and bigger - increase size of myofibrils |
| muscle cramps | - Involuntary contraction of 1st muscle Causes: overuse, strain, dehydration - Avoid dehydration, stretch |
Created by:
Shannonnev0822