Smooth Muscle Flashcards
Where is smooth muscle found?
Walls of hollow organs + blood vessels (but not capillaries)
How is smooth muscle contraction regulated?
Regulated by ANS, hormones and locally released substances. In the GI tract it is regulated by pacemaker cells
What are the smooth muscle containing organs?
Blood vessels GI tract Bladder, ureters and urethra Uterus Resp. system Vas deferens + corpus cavernosum Iris + ciliary body
What effects does smooth muscle have on blood vessels?
Controls their diameter, vascular resistance, distribution of blood and blood pressure
What effects does smooth muscle have in the GI tract?
Mixing + propulsion of GI contents
What effects does smooth muscle have on the urinary system?
Controls urine storage and micturition
What effects does smooth muscle have in the uterus
Responsible for labour
What effects does smooth muscle have in the resp. system?
Diameter of airways
What effects does smooth muscle have in the vas deferens and the corpus cavernosum
Controls erection an ejaculation
What effects does smooth muscle have in the iris + ciliary body?
Pupil diameter and focusing of lens
What is different about the actin:myosin ratio in smooth muscle compared to striated muscle?
Much higher
How is smooth muscle contraction regulated in the vascular system
ANS, autocoids + local hormones; vascular endothelium and blood-borne substances
How is smooth muscle contraction regulated in the resp. tract?
ANS, autocoids + local hormones
How is smooth muscle contraction regulated in the intestinal cells?
ANS, autocoids + local hormones, interstitial cells of Cajal
How is smooth muscle regulated in the myometrium?
Local hormones, autocoids, intrinsic rhythmicity
