Smooth Muscles!

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Smooth Muscles!
2013-03-23 21:25:24
Smooth Muscles

Smooth Muscles!
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  1. Smooth muscles are multinucleated or mononucleated?
  2. Smooth Muscles contains _______ but not  ______
    • Actin
    • Troponin
  3. WHat causes long term pain in muscles?
    Breaking down of muscle fibers
  4. In smooth muscles.... the control of binding is in ______ because _______ does not cover binding sites.
    • Myosin
    • Tropomyosin
  5. Smooth muscles contain long _____ with ___ _____.

    ATP attaches in such a way that it is considered __-__________

    Cross bridges are called _____ ____ because they are slow to detach

    Myosin heads cover the whole _____ _____
    • 1. Myosin with Light Chains
    • 2. Non-Phosphorylated
    • 3. Latch Bridges
    • 4. Myosin chain
  6. Smooth Muscle: Are Actin and myosin arranged the same as in cardiac and skeletal muscle?

    1/3 the ____ and twice the ____

    1/3 the MYOSIN and twice the ACTIN
  7. What is the actin to myosin ratio in smooth?

    What is the actin to myosin ratio in skeletal?
  8. Since actin and myosin are so _______ they can still be stretched more and produce ______

    They can be stretched ____ times its resting length and still contract.
    • Long
    • Tension
    • 2.5x
  9. Do smooth muscles have gap junctions?
  10. Do smooth muscles have T-tubules?
    Has less ______ than skeletal muscles.
    • NO!
    • Sarcoplasmic reticulum
  11. In skeletal muscle Calcium gates are ____ activated.

    In smooth muscle Calcium gates are ____ activated.
    • Skeletal = Mechanically Activated Ca Gates
    • Smooth = Chemically Activated Ca Gates
  12. Caveolae
    Small vesicles that cluster close to the cell membrane and contain gated Ca+
  13. What are the two types of smooth muscle?
    Where are they found?
    • Single Unit Smooth Muscle
    • Found in: Preg Uterus, Urinary & Gall bladder, intestinal tract, small diameter blood vessels, .
    • Multi Unit Smooth Muscle
    • Found In: Large arteries & airways of lungs, arrector pili, Intrinsic Eye muscles, Uterus (non preg)
  14. Single Unit Smooth Muscle
    1&2 Many fibers contract ___ as a response to ____
    3&4 This is accomplished by __ _____ that allow ___ to pass from fiber to fiber
    Often controlled by____ which have ____ for ____ and are innervated by ANS.
    Also can contract due to ______

    Multi Unit Smooth Muscle.

    • Single Unit Smooth Muscle
    • 1&2 Together/Stimulation
    • (think like func as single unit)
    • 3&4 Gap Junctions/Ions
    • Pacemaker / Receptors / Hormones
    • Stretching
  15. Multi Unit Smooth Muscle
    Have few __ __ each fiber contracts ___ of its neighbors.
    Innervated by _____
    Not stimulated by _____ or ____ cells.
    • Gap Junctions / Independently
    • ANS
    • Stretch / Pacemaker Cells
  16. Twitch of smooth muscle ____ differs from cardiac and skeletal.
  17. Skeletal = ____ Regulated and how does it phosphorylate?

    Smooth= ____ Regulated and how does it phosphorylate?
    • Skeletal = Actin regulated & Myosin Po4 itself.
    • Smooth = Myosin regulated & Myosin PO4 via Kinase
  18. Does smooth muscle  fatigue easily?
    Can reach maximum tension with only 25-30% of its ___-____ Active.
    • No!
    • Cross-Bridges
  19. What is contraction called in smooth muscle?
    What is the pathway?
    • Myosin-Linked Regulation.
    • Sliding Filaments dependent on Ca+
    • Depolarization opens Ca gates to outside too
    • Differs from skeletal muscle in that Ca+ acts on Myosin instead of actin and uses a Secondary messenger and enzymes.
    • Ca+ binds to calmodulin (struc simular to tropnin)
    • Ca+ calmodulin binds to protein kinase called myosin light-chain kinase (MLCK)
    • MLCK activates enzymatic phosphorylation of myosin light chain globular heads using ATP
    • Terminal PO4 transferred to each
    • Phosphorylated Myosin can bind to actin
    • Dephosphorylated by myosin light-chain phosphatase to make myosin let go (continuously active)
  20. How do contraction differ in smooth muscles VS skeletal muscle?
    Differs from skeletal muscle because:

    Ca+ acts on Myosin instead of actin and uses a Secondary messenger and enzymes.
  21. IN some smooth muscles actin is in a __-_____ state because it is attached to _______. In the presence of _____ ____ ____ _ it is seperated from ___ and now bind ____ bridges attach and cycle.
    • Nonbinding state  /  Caldesmon
    • Activated Protein Kinase C / Caldesmon
    • Latch
  22. What is the Latch state?
    How does it occur?
    Some smooth muscle stays contracted with myosin attached without much ATP.

    • 1) Occurs when PO4'ed cross bridge becomes dePO4'ed while still attached to actin.
    • 2)Allows for sustained contraction w/out the need of ATP
    • 3) Used by blood vessel smooth muscle against persistent pressure
  23. Type of smooth muscle stimulus that elicits contraction varies from skeletal muscle.

    Some use..... ( 3 things)

    No _____ stimulus is needed.
    Spontaneous Electrical Activity:

    some use pacemaker potentials, leaky to Ca+, and slowly depolarize until an AP is generated.

    No outside stimulus is needed.
  24. Smooth Muscle has no T-tubules and less S.R than in________ _______
    Skeletal muscle
  25. The ATPase activity is _____ in smooth muscle than in skeletal muscle so __-_____ rate is slower. This causes smooth muscle contraction to be ______ but to have greater ______ and ______ fatigue easily
    • Slower
    • ATP- Splitting
    • Slower
    • Endurance
    • Does not
  26. Spontaneous electrical activity:
    Some use ____ -_____ which are leaky to __ and slowly _______ until an AP is generated.
    • Pacemaker potentials
    • Calcium
    • Depolarize
  27. Varicosities in smooth muscle are filled with?
  28. Neurotransmitters: Smooth Muscle
    Are from the ________
    No _____ ____ _____ region
    One neuron ____ ____ fibers.
    One fiber supplied by several ____ & may be supplied by both sympathetic and parasympathetic _____.
    • ANS
    • No motor end plate region
    • Supplies several
    • Variscosities
    • Neurons
  29. Hormones: Smooth Muscle
    Binding to a receptor may lead to...(2 things)

    Some can cause contractions without change of membrane potential (Pharmacomechanical Coupling) by using...

    IP3 can cause....
    Na Pumps speed up....
    Change in membrane permeability or release of a second messenger

    • by using SM, IP3 can cause S.R to release Ca
    • Na pumps speed up removal of Na+ si the increase of Ca doesn't change membrane permeability
  30. Local factors:
    Paracrines, acidity, O2 concentrations, osmolarity and ion concentration can ____ _____ _______
    NO from endothelium causes smooth muscles to _____
    In smooth muscles, stretching opens stretch-______ Ca channels that lead to _______ and then _________.
    • Can change membrane permeability
    • Relax
    • Sensitive
    • Lead to Depolarization and then Contraction
  31. Proliferation (Rapid Increase) of Smooth Muscle Associated with _______________