Flashcards in Week 112 - Trauma Wrist Deck (28):
What do tendons link?
muscle to bone
What do ligaments join?
Bone to bone
What are the components of tendons?
Collagen, 95% type I, 5% minor collagen - type III, V, VI. provides the tensile properties.
Proteoglycans - regulate fibril size during growth and development
Fibrocartilage is present where the tendon inserts on the bone.
to dissipate compressive forces to reduce wear and tear
Major proteoglycan of cartilage
Three functions of ligaments?
Guide joint motion
Provide proprioceptive information
modified to form articular discs for shock absorption
rich in nerve fibers, stretching activates muscle contractions and prevents over stretching
pain fibers, autonomic nerve fibers supply their blood vessels
what is enthesopathy and provide an example
disorder involving the attachment of the ligament or tendon to the bone
Tennis elbow - pain at attachment of extensor carpi radialis brevis tendon to lateral epicondyle
golfers elbow -pain at attachment of extensor carpi radialis brevis tendon to medial epicondyle
Role of collagen in the tendon?
give the tissue high tensile strength and ability to resist stretching
lines a fibrous sheath through which the tendon glides and is lubricated by synovial fluid
which glkycoaminoglycan gives synovial fluid it's lubricating properties?
3 types of muscle cell?
skeletal striated muscle
cardiac striated muscle
neurotransmitters at a neuromuscular junction?
resting potential at a motor nerve terminal?
which receptor dies the neurotransmitter bind on the post synaptic membrane at a neuromuscular Junction
nicotinic receptors on the motor end plate. this causes the activation of ion channels and influx of sodium ions
after an action potential what breaks down the neurotransmitter?
the thick filaments in myofibrils are made from what protein
what three proteins make up the thin filaments in myofibrils?
in muscle contraction what initiates binding of cross Bridges to actin
what are the four steps involved in the cross Bridge cycle in muscle contraction?
1 cross Bridge formation myosin head attaches to an actin myofilament forming a cross bridge
2 the power stroke ADP and phosphate are released and the myosin head pivots and bends, changing to its bent low energy state. as a result it pulls the actin filaments towards the m line
3 cross Bridge detachment after ATP attaches to myosin, the link between myosin and actin weekens and the myosin head detaches
4 cocking of myosin head. as ATP is hydrolyzed to ADP and phosphate the myosin head returns to its pre stroke high energy position
what is the role of calcium in muscle contraction
calcium bind to specific sites on troponin, this causes the troponin to change shape and the tropomyosin to be moved away from the myosin Binding site
what is isometric contraction?
when a muscle develops tention but does not shorten. This occurs when muscles supports a load in a constant position or when it attempts to move a load that is greater than the tension developed by the muscle. For example lifting an object that is too heavy
what is isotonic contraction?
a contraction in which the muscle shortens while the load of the muscle remains constant. for example when a muscle shortens against a load and the load moves.
a contraction where the muscle is lengthening while resisting an external load . for example the length of the quadriceps femoris muscle while walking down stairs
what is the difference between slow twitch fibres type 1 and fast twitch fibres type 2?
slow twitch fibres contain myosin with lower ATPase activity
fast twitch fibres contain myosin with high ATPase activity
they have different rates at which they can split ATP this determines the cross-bridge cycling rate and shortening velocity
what are the three types of skeletal muscle fibre?
slow twitch type 1 low myosin ATP ase activity red fibres due to good blood supply and high myoglobin levels , resistant to fatigue
fast twitch type 2A high myosin ATP ase activity, red fibres, glycogen stores and enzymes for anaerobic glycolysis resistant to fatigue
fast twitch type 2B high myosin ATP as activity what fibres which glycogen stores and enzymes for anaerobic glycolysis rapidly
what order of motor units are recruited in an active muscle
first slow oxidative motor units second fast oxidative units third fast glycolytic units