Smooth Muscle Physiology Flashcards
What are the differences of skeletal cardiac and smooth muscle by type
Skeletal - straited and voluntary (somatic innervation by a and y motor neurons)
Cardaic - straited and involuntary
Smooth - untraited and involuntary
autonomic intervation (sympathetic and parasymapethic postganglionic fibres)
what is the differences of skeletal cardiac and smooth muscle by individual muscle fibres
Skeletal - large elgoanted cylindrical and possess multiple nuclei
Cardiac - large cylindrical and poss multiple nuclei
Smooth - small spindle shaped and posses one nucleuis
What does straited mean
what does voulntary and involuntary mean
straited means it contains scaramoeres
voluntary means you can control it will involuntary means it does it rest and digest and fight or flight
Function of Smooth Musucle in different locations
Vasculature
Airways
Urinary System
Vasculature - controls diameter regulated flow and pressure
Airways - controls diameter regualted flow and resistance
Urinary - propulsion of urine into ureters bladder tone tone of internal sphincter of bladder
Function of Smooth Musucle in different locations
Reproductive tract
Gatrintestinal tract
Skin
Male - secretion of sement
Female - proulsion of egg in fallopian tubes partiution in uterues
Skin - Pili erection
What is the difference in shape and function of smooth muscle in the artery bronchiole and colon
Artery - arrned cyclindrial around the arteries contract and relax for blood pressure
Bronchole - small airways of lungs with muscle allow reduce increase bore of airways increase partial pressure more surface area
Colon - medtaite repulsive movement some curvature
What is Multiunit smooth muscle
Allow
Word
how they function
example
electrical isolation of cells allows finer motor control
Tonic
Function individually
Iris and vas feernes
What is Unitary
Permit
Function
Example
Word
gAP JUNCTIONS PERMIT COORDINATED CONTRACTION
function as a syncytium
stomach urinary bladder and bronchioles
Phasic
What does Tonic and Phasic
Phasic constanltu engaged which provides a level of contraction (tone)
Tonic - slightly more contraction when stimulated controlling movements
Function of relaxation to contracted
Contrctile arhcolines to a cytoplasm in the cell membrane (dense bodies) rather than the structural protein
Net like structure muscle cross bridges are formed sliding mechanism is ended pulled relaxed and contracted
Xontractile machinery of Smooth Muscle
relies on sliding filament mechanism of generated during actin myosin cross bridge formation to facilitate contraction
Cross bridge formation and sliding filament in smooth muscle
- driven by a rise in CA which binds to calmodulin
- Ca calmodulin complex actovayes myosin light chain kinase
- Myosin light chiaan is phospahted on the myosin head
- Phosphoylation of myosin head ‘cock’s it and increases its ATPase activity reading it to interact with actin to form a cross bridge
Factors (2) affecting straited muscle cross bridge formation
CAS
incresed intraceullar Ca
stretch (Frank Sarling relationship)
Factors affecting smooth msucle cross bridge formation (3)
CIP
Increase intracellular Ca
Phophylation of myosin light chain kinase
Inhibition of myosin light chain phopahtase
What is calmodulin
Mulifunctional Ca2+ binding protien present in the cytoplasm of all eykarytoic cells
Ca can affect the protein and changes the light chain kinase
Calmodulin - Ca calmodium - CaM associated with a CaM kinase
What does relaxation of smooth involve
Drop in Ca and Depohoyrlation
How does Ca return to preexcitation cocentrations
Membrane bound Ca ATPase and Na Ca exchanges exepl calcium from the cell and calcium is sequestered into stores by sarco (endoplasmic reticulum calcium) ATPase (SERCA)
How does depohosylation occur
Myosin light chain phopahtase
How is innervation by autonomic nverous system in:
Aterial smooth muscle
Other smooth muscle
other point
Aterial - symapethic with noradrenaline
Other - both para and symapethic with acetylcholine
vast networks of nerual supply