joints and muscle action Flashcards
what makes up a motor unit?
several muscle cells inervated by 1 neuron makes a motor unit. their contraction is all or none. so if 5 muscle cells are innervated by the name neuron, that makes a motor unit and when that motor unit is called in to contract, all 5 of those muscle cells are contracting at the same time
what are the three types of contraction?
concentric- the muscle cells get closer together fast (like a curl move)
isometric - thats just holding something out and keeping it there. the muscle length does not change
eccentric- when you’re slowly lowering your arm. the muscle lenghtens. This is like the pronation curls to resisting.
what are the three types of joints. which one allws the most movement and the least? where are they found?
fibrous joints are the least motile. These joints are made of ttwo fibrous capsules encapsulates a fibrous tissue interior. these guys dont move at all, like your scull
the second is cartilagenous joints, with two fibrous capsules encapsulating a catilagenous interior. This is found in the intervertebral disks, they move only a little
the most motile of the joints are hte synovila joints. it has a larger fibrous capsule with sinovium. This is the movable joints of the shoulder, hip elbow.
osteoatherits happens in what kind of joint?
synovial joint
how many trap fibers are there?
three. and you can tell by looking closely atthe muscles. they point in the direction they are working to. If you put your point of origin on the scapula. You have 1 pointing up, two pointing inside and 3 pointin down. thats the direction of their movement
what is the inside agbaja motion called and which muscle does it?
its called translational or retration (outside in) and it is donne by the middle fibers of the trap
how do you decide which end moves towards which?
both sets of muscles can move but its about which is the fixed end and which is the movable end/ the fixed end is called the origin and the movable end is called insertion. insertion moves towards the origin. this can change depending on location of the body
what relation of muscle to plane give you the most efficient movement?
when the muscle is perpendicular to the plane, thats when it moves the best. 90 degree angle is most effective and 0 degree means that muscle isnt playing a role in that action
