Module 4 - Muscles Flashcards by vlad zuban

Locomotion requires work to overcome which forces?

Friction, gravity/loads

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Locomotion occurs in accordance with which law?

Newton’s 3rd law: A physical body will remain at rest, or continue to move at a constant velocity, unless an external net force acts upon it

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Horizontal movement in water requires much less energy than vertical movement (true or false?)

False - vertical movement requires little energy due to buoyancy

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Which 2 forces do birds have to overcome in order to fly?

Gravity & air resistance

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What are contour feathers?

Feathers used for flight. Made up of barbs stuck together via interlocking barbules

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3 groups of flight feathers?

Primaries, secondaries, tertiaries

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Properties and function of primary feathers?

Largest & most distal. Most birds have 10. If damaged or lost -> cannot fly. They propel birds thru air

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Properties and function of secondary feathers?

Run along “arm” of wing and sustain bird in air giving it lift. Numbers vary among spp. Perch birds ~9 or 10. Up to 20 in grouse. If 1/2 are removed bird can still fly

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Properties and function of tertiary feathers?

Fewest flight feathers.

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Properties and function of tail feathers (rectrices)?

Steering & balancing, braking. Usually 10 - 12.

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Another term for wing & tail feathers?

remiges & rectrices

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What adaptations have flying geckos evolved?

Large webbed feet, lateral skin flaps along body, broad flattened tail

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What adaptations have flying snakes evolved?

Ability to spread their ribs widely into U-shaped half-cylinder and undulate up to 100m

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Where do animals store elastic potential energy?

Muscles & tendons

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Why does crawling or slithering use more energy?

Because of higher frictional forces

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Put these animals in order from fastest to slowest: P. falcon, quarterhorse, greyhound, elephant, lion/gazelle, pronghorn antelope, human, kangaroo, cheetah, giraffe, sloth

P. falcon, cheetah, pronghorn antelope, lion/gazelle, quarterhorse, greyhound, giraffe, kangaroo, human, elephant, sloth

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3 skeletal muscle fibre types?

Slow-oxadative (type I) fibres, fast-oxadative (type IIa) fibres, fast-glycolytic (type IIb) fibres

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What are the main differences between the 3 skeletal muscle fibre types?

Speed of contraction(fast or slow), oxidative or glycolytic

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T or F - slow oxidative (type I) fibres have more mitochondria than fast-glycolytic (type IIb) fibres

True

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T or F - slow oxidative (type I) fibres have a higher glycogen content than fast-glycolytic (type IIb) fibres

False

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What is the fibre colour of the 3 fibre types?

slow-ox (type I) - red, fast-ox (type IIa) - red, fast-gly (type IIb) - white

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Myotubes give rise to..?

sarcomeres

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T or F - Myoblasts give rise to contractile proteins

False - myofibres give rise to contractile proteins

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Early myoblasts give rise to..?

slow, fast & intermediate fibre types

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First wave gives predominantly which fibres?

slow-twitch

Late myoblasts give rise to which fibres?

fast-twitch

What happens to latest myoblasts that don't get to fuse?

They become satellite cells (stem cells) for muscle DNA input

Characteristics of type I (slow-oxidative) fibres?

Small diameter, long, lean-like. Fatigue-resistant. Aerobic activity. FA's main energy source. low-level force production (stranding, grazing, walking)

Characteristics of type IIa (fast-oxidative) fibres?

Moderate resistance to fatigue. For prolonged anaerobic activities with relatively high force output. creatine phosphate & glycogen main energy sourceTrotting & cantering.

Characteristics of type IIb (fast-glycolytic) fibres?

Fast rate of ATP metabolism. Fast contractility. Very sensitive to fatigue! For short, anaerobic, high- force activities ie. jumping, galloping.

Speed of muscle contraction depends on..?

Load & Myosin ATPase activityof contracting fibres (fast or slow twitch)

T or F - Oxidative fibres produce more lactic acid than glycolytic fibres

False - oxidative fibres use ox. phos. thus producing minimal lactic acid. Glycolytic fibres use anaerobic energy metabolism thus produce lots of lactic acid

T or F - Fast glycolytic (type IIb) fibres contain many mitochondria.

False - they have few mitochondria but many glycolytic enzymes

Why are glycolytic fibres larger in diameter than oxidative fibres?

Greater abundance of actin & myosin filaments - produce lots of energy/tension

T or F - type IIb fibres are recruited in later stages of endurance events

True - when glycogen runs out type I & IIa fibres -> fatigued

T or F - type I fibres are recruited 1st because they have the highest firing threshold

False - they are recruited 1st because they have the LOWEST firing threshold

T or F - Type I motor units are always recruited 1st regardless of workout intensity

True

T or F - Number & type of muscle fibres in an individual is genetically determined

True

T or F - Quarterhorse has more type II muscle fibres than type I

True

Which muscle fibres are predominant in canines?

oxidative

What is the main metabolite in dogs?

Free fatty acids (fat)

Generally, hindquarter muscles contain more type? fibres whilst forelimb muscles contain more type? fibres

hindquarter - type II fibres, forelimb - type I fibres

How is oxidative capacity improved?

Regular endurance exercise -> increased mitochondria, capillaries and myoglobin to these fibres

Explain the process of muscle hypertrophy

Anaerobic (high intensity training) -> increase diameter of fast-glycolytic fibres by increasing synthesis of myosin & actin filaments

Muscle fibre adaptations in response to training depend on which 4 factors?

Age, previous training & type of training, genetics, intensity & type of work

Explain increased capillarisation

may be due to increased number of capillaries and/or decrease in fibre size -> improved delivery of O2 to muscles for ox. phos. Improved delivery of glucose, and removal of CO2, lactate & H ions from contracting muscles.

How long does increased capillarisation take to occur?

several months with endurance training

What is increased transit time?

Dependent on increased capillarisation -> slower blood flow thru muscle -> more time for equilibrium between O2 in blood & working muscle. Significant increase in O2 uptake in TB - for increased mitochondrial metabolism

Describe process of increased O2 to muscles (include details of O2, CO2, H+, and acidity)

O2 bound to haemoglobin -> muscles -> O2 disassociates while CO2 or H+ taken up to be excreted (H+ acts as buffer to minimise acidity)

What are the 3 different responses to training?

1. increase arterial-venous difference 2. increase oxidative capacity 3. increased activity of aerobic enzymes

Describe increased arterial-venous difference

+ capillary density -> + transit time -> +O2 unloaded at muscle -> +extraction of O2 from bloodstream

Describe increased oxidative capacity

Training - type IIb fibres -> + type IIa fibres -> + capacity of muscles to use O2 for aerobic metabolism

Describe increased activity of aerobic enzymes

Improved activity of citrate synthase & 3-hydroxyacyl-CoA dehydrogenase

T or F - Training decreases FFA mobilisation from adipose tissue

False - training increases FFA mobilisation

Benefit of using fat as a fuel source

Has glycogen-sparing effect (delays onset of fatigue)

T or F - Fat can only be used as a major fuel source during high exercise intensities

False - low to moderate

How does increased [myoglobin] aid muscle performance? Which muscle fibres are involved?

+ O2 storage capacity esp in type I fibres

Benefits of increased glycogen storage capacity

+ fuel stores for aerobic & anaerobic energy production. (may increase by double post-training in horses)

Muscle mass in normal horse breed?

~42%

Muscle mass in mature thoroughbred?

~55%

Equines have highest % of this fibre type

Fast twitch

How does an animal increase its speed?

By recruiting more muscle fibres -> + force. Recruitment is selective (not random)

What are the effects of training?

Structural & chemical changes in muscle fibres -> aerobic/anaerobic capacity. Chemical changes ([enzyme] & stored energy substrates)

T or F - Twitch type changes with training

False - fibres remain the same despite different training exercises

T or F - Aerobic conditioning affects aerobic capacity of fast oxidative & fast glycolytic fibres

True

How does aerobic conditioning increase oxidative capacity of muscles and which 2 pathways are used?

+ mitochondrial density -> + enzyme activity in tricarboxylic & lipid metabolic pathways -> + oxidative capacity of muscle

T or F - Aerobic condition favours the use of fats rather than carbs

True

What are the metabolic benefits of endurance training?

Sparing effect on muscle glycogen stores & + oxidative muscle fibres

Module 4 - Muscles Flashcards

(68 cards)