Lecture 5 Smooth Muscle PDF

5 Here noth Muscle ↓ V...

5 Here noth Muscle ↓ V diagonally) ↑ - thick+ thin filaments (oriented source - X striations cat-released dep.+ 2mages by plasma mem filaments anchored 2) Extracellular Cat · thin to plasma - enter via voltage + ligand-gated channels membrane or dense bodies What & contractions filament contraction - shortening-ballooning - spontaneous electrical activity plasma · > in mem · neurotransmitters released by autonomic nerves - bridge formation dependent on Cast · hormones * * & Cytosolic Ca >↑ Ca-calmodulin - > - ↑ of cell surrounding · activity myosin- changes in Chem. composition ECF Contraction light -+ ↑ = chain of stretch activity phosphorylation myosin · * relaxation dependent on myosin dephosphorylation by myosin light-chain phosphate * single-unit smooth muscle CHRONOUS activity * AP sent to other cells via g junctions Chewing ① controlled by somatic nerves to mouth+ jaw Swallowing of ② mechano-R : pressure of food on hard plate/gums * food-back of mouth by tongue - activation pressure- R in pharynx ↓ medulla oblongata blocks nasal ~ - > - cavity center & suft elevates inhibit hold jaw closed impulses sent to swallowing plate muscles mu ↳ inhibit epiglottis - ↓ pressure = new cycle of contractions resp. I close glottis > - foodepharynx = ~ prevent aspiration ③ Saliva esophageal sphincter food - esophagus : 3 salivary glands cover glottis > - upper relax = &. right m ↳ * emageal : lower esophageal sphincter relaxed phase when swallowing Sa sectionis peristaltic waves push food- stomach- if large food bolos : secondary esophageal mechano-R send signal to swallowing center peristalsis functions meals : closure of lower esoph. sphincter prevents stomach moist/lube food acid back (gastroesophageal reflux-heartburn) · flow ↳ digestion of fats amylase by - lil common in pregnancy be] dissolves food - (i) 1) & abd pressure kills bacteria 2) fetus - pushes esoph through diaphragm > - thoracic cavity