Term
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Definition
| A single neurone and the muscles fibres that it innervates. |
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Term
| What is a motor neurone pool? |
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Definition
| All motor neurones supplying one muscle. |
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Term
| What is a neuromuscular junction and what neurotransmitters does it use? |
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Definition
| Where the terminal bouton of an axon meets the motor end plate of a muscle. Use acetylcholine as a neurotransmitter and has nicotinic recptors. |
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Term
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Definition
| Roughly equivalent to a cell, polynuclear, may be up to 10cm long. Contains sarcoplasm (muscular cytoplasm) and has a sarcolemma (muscle fibre membrane) |
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Term
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Definition
| Deep invaginations of the sarcolemma to the centre of the fibre allowing for fast depolarisation of internal |
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Term
| What is the sarcoplasmic reticulum? |
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Definition
| Enlarged endoplasmic reticulum, associated with T tubules, releases Ca2+ on stimulation |
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Term
| What is a motor end plate? |
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Definition
| Sarcolemma directly under an axon with nicotinic receptors and in foldings increasing surface area. |
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Term
| In the action potential transmission through a muscle, what occurs in response to the action potential penetrating transverse tubules? |
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Definition
| Na+ in the sarcoplasm stimulates sarcoplasmic reticulum to release CA2+ which diffuses into myofibrils |
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Term
| What are the steps between CA2+ binding to troponin and the formation of a cross bridge? |
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Definition
| Troponin pulls tropomyosin out of the way clearing a myosin binding site. Myosin head binds to actin filaments therefore forming a cross bridge. |
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Term
| What is a muscles sarcomere? |
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Definition
| The contractile unit of a muscle extending from one z line to the next. |
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Term
| What are A bands in muscle? |
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Definition
| dArk bands which remain the same length on contraction. |
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Term
| What are I bands in muscle? |
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Definition
| lIght bands which reduce in length on contraction as does the sarcomere. |
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Term
| ATP binding to the myosin head allows it to do what? |
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Definition
| Dissociate from the actin filament. |
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Term
| What reaction allows the myosin head to recock? |
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Definition
| The split of ATP to ADP and Pi |
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Term
| What is the quickest source of ATP in the body? |
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Definition
| Phosphocreatine- phosphorylates one ADP molecule to one ATP, although there are limited PC stores |
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Term
| Which muscles especially use anaerobic respiration to produce ATP and how? |
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Definition
| White fast twitch fibres by the split of glycogen to lactic acid producing 3 ATP |
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Term
| What is the basic reaction in aerobic respiration and how much ATP does it produce? |
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Definition
| Glucose splits into CO2 and water producing 38 ATP. |
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Term
| What is the slowest source of ATP? |
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Definition
| Free fatty acid oxidation, splitting into CO2 and water producing high ATP yield (between 100-150) |
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Term
| What is an isotonic muscle contraction? |
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Definition
| Load/weight on muscle remains the same, whilst muscle shortens |
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Term
| What is an isometric muscle contraction? |
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Definition
| Despite contraction of muscle, the load remains in constant position, supported by muscle |
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Term
| What is an eccentric muscle contraction? |
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Definition
| Force acting against muscle is greater than that exerted by contraction |
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Term
| What is the type I muscle fibre? |
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Definition
| Slow twitch, oxidative fibre, red in colour, high in myoglobin and resistant to fatigue. |
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Term
| What is the type IIa muscle fibre? |
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Definition
| Fast twitch, oxidative muscle fibre, red in colour with high myoglobin content, also contains glycogen stores, resistant to fatigue. |
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Term
| What are type IIb muscle fibres? |
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Definition
| Fast twitch, glycolytic fibres, white in colour with low myoglobin, high glycogen stores, fatigue rapidly. |
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Term
| What factors affect contraction strength? |
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Definition
| Number of motor units required (more units more tension), frequency of impulses (more impulses more tension) |
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Term
| What 3 factors may cause peripheral fatigue? |
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Definition
| Contraction failure, lactic acid build up and ADP & Pi build up. |
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Term
| What may cause central fatigue? |
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Definition
| Appropriate action potentials not being fired by the cerebral cortex, due to tiredness or lack of motivation. |
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Term
| What four macromolecules is the extracellular matirx comprised of? |
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Definition
| Collagen, elastin, glycoprotiens and proteoglycans. |
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Term
| What do Fibrillar collagens (types I, II, III, V & XI) do? |
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Definition
| Rod-like molecules, quarter-stagger arrangement, provide mechanical strength. |
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Term
| What do Fibril-Associated Collagens (types IX, XII, XIV, XVI, XIX) do? |
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Definition
| Link fibrillar collagens to one another or to ECM components – known as FACIT collagens. |
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Term
| What do Transmembrane Collagens (types XIII, XVII) do? |
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Definition
| Function as adhesion receptors. |
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Term
| What cells types are tendons comprised of? |
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Definition
| Tenocytes and fibroblasts. |
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Term
| What collagen type fibrils are orientated in the direction of force applied to the tendon and why? |
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Definition
| Type 1 collagen (95%), have great ensile strength meaning the tendons can be stretched and not broken. |
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Term
| What other collagne microfibrils bind to type I fibrils and why? |
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Definition
| Type VI, giving thicker fibrils and therfore increased mechaincal strength |
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Term
| What is the role of proteoglycans in tendons? |
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Definition
| Regulate colagen size and bind water. |
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Term
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Definition
| Bone-tendon / bone-ligament junction, enthesis fibrocartilage reduces wear and tear |
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Term
| In what connective tissue would you find increased proteoglycan concentration (aggrecan)? |
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Definition
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Term
| What is the collagen composition of ligaments? |
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Definition
| 90% type I and 10% type III |
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Term
| What are the four functions of a ligament? |
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Definition
| Attach muscle to bone, send proprioceptive signals to the brain, act as shock absorbers and 'tie down' other soft tissues to bone. |
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