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Physio Ch 9 part 2
Question | Answer |
---|---|
smooth muscle structure includes | diagonal chains and dense bodies |
diagonal of...and are...meaning there are no... | actin and myosin...unstriated..sarcomeres |
dense bodies are the | actin and myosin |
actin has...but doesn't have... | tropomyosin...troponin |
tension for smooth muscle has a...compared to skeletal | wider range of tension generating length |
in smooth muscles, stretch can ...like in the... | still produce maximal force...stomach when food stretches the stomach it is still able to contract to digest food |
types of smooth muscle include | multi and single unit |
multi unit means there are... | multiple innervations of neurons to smooth muscle |
single unit means there is a...and all | single innervation (one neuron to stimulate all cells)...cells form one unit |
single units...and are connected via... | contract as a single unit...gap junctions which means electrical conduction |
smooth muscle is innervated by the | autonomic system (symp and para depending on the muscle) |
smooth muscles contain | axons and myofibers |
axons are...containing | nerve fibers...varicosities with synaptic vesicles with neurotransmitters |
the myofibers of smooth muscle do not have | motor end plates |
type of smooth muscle stimuli can be | excitatory or inhibitory |
excitatory stimuli involve...to open which leads to... | voltage gated ca channels...depolarization |
ca in smooth muscles causes two things | APs and release of neurotransmitters |
inhibitory stimuli cause...or... | stable resting potential...hyperpolarized cell |
single unit is activated by...which cause... | pacemaker cells...pacemaker potential |
pacemaker potentials replace...and innitiate... | graded potentials...depolarization to threshold |
pacemaker cells have | slow waves |
single units are connected by....have what kind of activity...and whaqt kind of innervation.... | gap junctions...synchronus(electrical are faster)...autonomic |
single units have some...as well as from...which means they are not | stimulation by stretch...hormones...just neurally driven |
multi unit smooth muscles operate more like...and involve...as well as what type of innervation | skeletal...individual neural stimulation...autonomic innervation |
mosst common type of muscle | is a combination of single and muli units |
smooth muscle membranes haveno...but they do have... | t tubules...voltage gated ca channels for depolarization |
voltage gated ca channels change | membrane potential as ca goes into the cell |
stimulus for smooth muslce membrane may be | excitatory, inhibitory or both |
types of stimuli for smooth muscle include | neurotransmitters (general and common), hormonal, other chemicals or extracellular conditions like pH in the GI tract), stretch and pacemaker cells |
pacemaker cells produce pacemaker potentials which occur because of | leak channels where + ions go in until threshold is met = automatic threshold |
pacemaker potentials cause contraction without | external stimulation (outside of that cell - - - neural) |
pacemaker cells' slow waves do not mean an...will occur | AP |
slow waves are for | ion change |
slow waves have a..ion flux across membrane in... | regular..both directions |
slow waves need | additional excitatory stimulus in order to cause AP |
smooth muscle excitation-contraction coupling goes from | excitation to muscle contraction |
excitation-contraction coupling (ECC) contains a...which is the activity... | latent period...between stimulation and cross bridge cycling |
latent period involves...which comes from... | ca going into the cell...extracellular (interstitial fluid) and intracellular (sarcoplasmic retic) |
extracellular ca sources have the.. | most ca, voltage gated CA channels and ligan gated ca channels |
the ligand gated ca channels | augment the postive charge inside the cell |
intracellular ca sources are | less developed than skeletal muscles and only some ca is here |
muscle contraction involves | cross bridge cycling and latch state |
muscle relaxation involves | ca sequestering |
thin filaments of smooth muscle has...but not... | actin...troponin |
what takes place of troponin? | calmodulin |
calmodulin binds...and also binds and activates... | ca...cytostolic myosin light chain kinase |
myosin light chain kinase is an | enzyme for binding phosphate to myosin |
myosin contains...which cause | myosin light chain kinase...phosphorylation of myosin light chains |
smooth muscle cross bridge activation mechanisms | ca influx activates calmodulin which binds to ca and activates myosin light chain kinase which allows you to phosphorylate myosin light chain to change orientation on myosin head |
after phosphyrlation of myosin light chain changes shape on myosin head... | myosin head is in position to form cross bridges |
cross bridge cycling only requires...and step three keeps...meaning you dont need.. | atp for the power stroke...myosin in correct orientation...second atp action |
lastly in smooth muscle cross bridge cycling, myosin | light chain phosphatase dephosphorylates myosin for relaxation |
dephosphorylating myosin means the head | is not in the right position |
smooth muscle relaxation invoplves the...and.... | ca atpase...na/ca ccountertransport activity |
smooth muscle relaxation what is greater than what | myosin light chain phosphatase activity > myosin light chain kinase activity |
enzymes are | constantly working so it is a matter of balance between kinase and phosphatase |
during relaxation the myosin head...and no... | shifts away from actin...cross bridge formation |
latch state of relaxation... | holds contraction without expending more atp |
latch state the myosin may be...but still... | dephosphorylated...attached to actin |
latch state maintains...there is no..., low...and... | tension (continuous contraction)...shortening of myofiber...atp use...long, slow contractions w/o fatigue |
cardiac muscle cell structure is...which contains... | striated...sarcomeres, t tubules, ca storing sarcoplasmic reticulum |
cardiac muscle is...which...and contains... | intercalated...holds cells together...desmosomes |
desmosomes are | proteins that extend between two cells |
cardiac muscle cells are connected via...and they...which allows for... | gap junctions...branch...multidirectional squeezing |
cardiac muscle is self...by... | stimulated...pacemaker cells |
nervous system only | influences, it does not cause stimulation of cardiac muscles |
neural control of smooth muscle by the sympathetic division | innervates entire heart to make it pump harder and faster |
parasymp control of cardiac muscle involves which nerve and what does parasymp do | vagus, cranial X...innervates primarily the atria so it only effects heart rate (slower) |
cardiac action potentials involves | muscle action potentials to make the contraction |
cardiac action potentials also involves...which initiates... | pacemaker potentials...the heartbeat |
pacemaker potentials in cardiacmuscle send | signals to cells to generate APs in cells |
excitation-contraction coupling involves turning | electrical activity to mechanical energy |
cardiac muscle has a...which is the... | refractory period...inability of cardiac muscle contractions to produce fused tetanus |
if fused tetanus could occur in cardiac muscle then the | heart could not re-fill with blood bec no relaxation occurs |
cardiac muscle has no | latch state |
cardiac muscle cell AP is also called | ventricular action potential |
cardiac APs look...and are initiated by... | different than neuron or skeletal muscle APs...pacemaker cells |
resting potential of cardiac muscle is...and depolarization occurs via... | -90 mV...na voltage gated channels opening and most k leak channels closed |
plateau phase is the...where | delay period...na voltage gated channels are inactive |
plateau phase involves | l-type voltage gated ca2+ channels open |
open l type voltage gated ca2+ channels involve...ca...gradient in and... ca2+ =... | modified DHP receptors...follows...k out |
repolarization of cardiac muscle means l type voltage gated ca2+ channels...and voltage gated... | close...k channels open |
pacemaker potential of cardiac muscle are called | cardiac conduction system APs |
pacemaker potentials look...and are... | different than neuron APs...self initiated |
pacemaker potentials are linked | to other cells through gap junctions |
cardiac muscle fiber AP involves | pacemaker and conductino fiber stimulation |
latent period of cardiac muscle contraction | cytostolic ca opens sarcoplasmic retic, ca released, ca binds to troponin, tropomyosin is shifted |
tropomyosin shift causes...which causes... | cross bridge cycling...muscle contraction |
muscle relaxation involves | pumping ca out and sequestering it |
cardiacc muscle tension development has a...AP because of the... | longer...plateau phase |
cardiac muscle tension development has a...refractory period involving... | longer absolute...plateau phase and longer depolarization with no tetanus |
cardiac muscle tension development has...tension because of | longer...plateau phase and longer depolarization |
cardiac muscle must be | partly relaxed to re-stimulate |