Muscles General Flashcards
what are the 3 muscle types?
smooth (visceral) muscle, cardiac muscle, striated (skeletal) muscle
which muscle types are involuntary? which are voluntary?
involuntary: smooth and cardiac
voluntary: striated
where is smooth muscle found?
blood vessels and internal organs
how is smooth muscle organized?
no banding - loose organization of actin and myosin
where is cardiac muscle found?
heart
how is cardiac muscle organized?
striated
where is striated muscle found?
MSK system
how is striated muscle organized?
visible banding, highly organized from sarcomeres to identifiable muscles
what is a sarcomere?
the basic contractile unit
what is the organization of striated muscle from smallest unit to largest unit?
sarcomere –> myofibril –> fiber –> fiber bundle –> muscle head/belly
what is another name for fiber bundles?
fasciculi
what is the fascia around the muscle fiber called?
endomysium
what is the fascia around the fasciculi called?
perimysium
what is the fascia around the muscle bellies called?
epimysium
what separates muscle bellies into definable groups?
epimysium
label this image
A: bone
B: tendon
C: epimysium
D: endomysium
E: permysium
F: blood vessel
G: muscle fiber
H: fascicle
how do muscles attach to bone?
through tendons
what is the muscle origin?
proximal attachment point to tendon/bone
what is the muscle insertion?
distal attachment to tendon/bone
are tendons contractile or elastic?
elastic
what are 2 mechanisms to prevent wear on tendons?
sesamoids
bursae and sheaths
what are bursae/sheaths?
fluid-filled cushions
what is the difference between bursae and sheaths?
bursae: on one side of tendon
sheath: wraps all around tendon
what is muscle power determined by?
fiber orientation and fiber number
can muscles pull AND push? or only one?
muscles only pull
what are the 5 muscle architectures?
strap, spindle/fusiform, unipennate, bipennate, multipennate
what is the difference between fiber orientation in strap/fusiform muscles and pennate muscles?
strap/fusiform: fibers run parallel to line of action
pennate: fibers run at an angle to line of action
label the muscle architectures
1: strap
2: spindle or fusiform
3. unipennate
4. bipennate
5. multipennate
how much can muscles contract relative to their length?
~50%
what is the relationship between muscle power and contractile distance?
the more contractile distance, the less power
what is the contraction vs power of spindle/strap muscles?
can contract over long distances, limited power
what is the contraction vs power of pennate muscles?
generate lots of power, but only over short distances
what type of motion do muscles produce at joints?
angular motion
what are the levers in the MSK system?
bones
what are the forces in the MSK system?
muscle force or external force
what are the fulcra in the MSK system?
joints
what are agonist and antagonist muscles?
antagonist muscles contract when agonistic muscles relax (and vice versa)
ex. biceps and triceps
what are synergist muscles?
function in tendem with other muscle(s)
what are fixator muscles?
keep joints stable
