Flashcards in Physiology of Smooth Muscle (In Class)- Karius Deck (22)
What are some requirements of smooth muscle?
Contract and maintain contraction for a long period
contract periodically to mix contents in organ
maintain shape of organ
active tension when stretched
relatively low ATP
where is smooth m. found?
viscera, vasculature (particularly arteries), GI tract, GU tract (also: respiratory tract and eye)
what do thin filaments anchor to?
what do thin filaments contain?
actin (2x skeletal m.); tropomyosin; NO TROPONIN
what do the thick filaments consist of?
what is within the thick filaments?
kinases and phosphatases
Is smooth m. all the same?
no, has to be different based on different functions
what kind of innervation does smooth m. (esp of gut and trachea have)?
what is the extrinsic innervation of smooth m.?
Autonomic nervous system
what does Ach do in GI?
excites some smooth m. (sphincters) may inhibit other (relaxation)
what does NE or Epi do?
contraction of vascular smooth m; inhibits gut smooth m.
Nitric Oxide does what?
major inhibitory influence on smooth m.; works via cGMP pathway
one major difference between smooth m. and skeletal?
smooth m. can be directly inhibited
smooth m. has what kind of receptors?
adrenergic, mAchR, non for NO because it is lipid soluble
whereas skeletal m. can only be activated by NMJ what can smooth m. be activated by?
things in blood (hormones)
what are some hormones that elicit GI contraction?
epinephrine, CCK, motilin, etc.
paracrine agents that cause smooth m. contraction?
what's a 3rd way smooth m. can be activated?
what frees the myosin head from being bound to actin?
when calmodulin is no longer activated what is activated?
is an AP required in smooth m.?