Muscle & Tendon Flashcards
Visceral found
Blood vessel
Gut
Skeletal found/fx
Attached to skeleton via tendons
Responsible for movement
Posture
Skeletal muscle cell formation
Some mesenchyme cells in each myotome diff into precursor skeletal m cells (myoblasts)
Myoblasts fuse end to end form elongated multinucleated myotubes
Contractile proteins laid down pushing nuclei to periphery and form mature muscle cell/myofibres/muscle fibres
Some myoblasts persist as precursors and may take part in m repair
How is the body like a system of levers
Joints act as pivots/fulcrum
Skeleton is load being moved
Muscle provides the effort
Joints can act as pulleys sometimes where pass over more than one joint to insert on bone changing tithe direction of pull
Energy conversions
Elastic E is important for fx when stretched the gators kinetic E
Types of levers
Fulcrum between load and effort
Load between fulcrum and effort
Effort between fulcrum and load
Antagonists
A pair of muscles usually act in opposition to each other
Eg triceps & biceps brachii mm
Synergists
Muscles can act together
Eg Biceps brachii & brachialis mm
Origin
Proximal or central attachment of tendon to bone (less movement)
Insertion
Distal or peripheral attachment of muscle tendon to bone (more movement)
Belly
Main part with muscle fibres
Head
Part of belly nearest the origin of the muscle
Fat muscles
More force gen capacity
More contracting muscles on parallel
Long muscles
Contract faster
More contracting units in series
How does muscle cell orientation affect contraction
Force and velocity of m contraction
Force gen capacity enhanced at expense of speed and shortening capacity
Muscle patterns
Strap eg zygomaticus Spindle/fusiform eg biceps brachii Unipennate eg abductir pollicis longus Bipennate eg subscapilaris Multipennate eg serrated ventralis
Muscle structure
Myosin and actin Myofibrils (divided into sarcomeres) Muscle fibre Fascicles Muscle (tendon and muscle fibres)
Metabolic pathways giving way to ATP
Creative phosphate + ADP
(Fast & short lived)
Anaerobic pathway - using glucose &a glycogen (fast & shortlived)
Aerobic - uses O2 via myoglobin & mitochondria (slow &a long lived) efficient
Types of muscle fibre
Proportions vary in diff muscles due to fxal need type 1
2a
2b
Type 1
Slow twitch
Aerobic
Red fibres
Type 2a
Fast twitch
Aerobic and anaerobic
Intermediate fibres (not present in all mammals)
Type 2b
Fast twitch
Anaerobic
White fibres
Gen lots of lactic acid
Variations in fibre make up
Species evolved to have diff proportions to suit lifestyle
Varieties within species naturally/ bred to have diff proportions of muscle fibre types
Innervation of skeletal m
Fibres dev according to size of motor neuron
Fibres atrophy if they lose their innervation
Growth of skeletal m
As skeleton grows muscle fibres lengthen due to addition of sarcomeres in series
Opposite can also occur
Response to exercise of skeletal m
Ex regime incr oxidative met capacity of motor units - CV system response
Regular max strength ex cause hyper trophy (more sarcomeres in parallel)
Athletes include appropriate max strength ex in regime
Response to injury of skeletal m
Fibrosis (replace m fibres with fibrous scar tissue)
Hyperplasia (incr no of m fibres is more controversial) seems likely injured m segments can repair with the help of satellite/other stem cells their is evidence that this could happen
Linking m to skeleton
CT surround m fibre
This merges to form tendon/aponeuroses which merged with bone
When muscle contracts enough skeleton will move
How are Muscle cells held together
CT compartments
Indi cells anchored but have some independence of movement
Composed of dense and loose irregular CT continuous with deep fascia
Composition of CT surrounding m
Mainly fibroblasts GS collagen some elastic fibres
3 CT layers
Endomysium (m cell)
Perimysium (fascicles)
Epimysium (whole m)
Tendon
Dense regular CT
Tight packed longitudinally running collagen fibres together with the cells which produce the collagen - fibroblasts and some GS. V high tensile strength but flexible *
Aponeuroses
Flat sheet of dense regular CT form very spread out attachment
Tight packed longitudinally running collagen fibres together with the cells which produce the collagen - fibroblasts and some GS. V high tensile strength but flexible *
Muscle is anchored to ? Via tendon/aponeuroses
Bone
Other tendons/aponeuroses
What attaches m directly to bone
Sharpeys fibres
Musculotendinous jctn
Link between m fibres and CT needs to withstand high levels of stress during force transmission
Protection methods for tendons
Sesamoid bones
Synovi bursae
Synovial tendon sheaths
Muscle types
Smooth/visceral
Cardiac
Skeletal/voluntary/striated
Synovial membrane composition
Loose CT Discontinuous layer of cells close to sy fluid space Other cell types (adipocytes etc) Collagen, elastin and reticular fibres Semi fluid GS
Cells in sy membrane
Some secretory - sy fluid nourish and lubricate cart
(HA - GAG is viscous and glycoproteins lubricin) both lubricate
Some phagocytic (recycle sy fluid)
Blood/n supply
In CT
Smallest vessels and single n fibres in endomysium
Largest in outer epimysium
Tendons have ltd blood supply so heal slowly
See hist lab book and ans qs on sheet
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