Introduction To Endocrine Physiology

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Introduction To Endocrine Physiology


Lecture number:
13
Pages:
5
Type:
Lecture Note
School:
University of Southern California
Course:
Bisc 307l - General Physiology
Edition:
1
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BISC 307L 1st Edition Lecture 13 Current Lecture  Types of Smooth Muscle o o How the cells behave o Left: Single unit  Blood vessels (vasodilation and constriction), intestine (motility), full term uterus (contractions)  Coupled by gap junctions (electrical and metabolic)  Excitation spreads through gap junctions- whole thing behaves as a unit  Varicosities releasing transmitter o Right: Multi-Unit  Eye (iris (pupil), ciliary body-change shape of lens (accommodation)) non pregnant uterus  Cells are individual not coupled by gap junctions  Each cell responds individually o Some smooth muscle doesn’t receive any innervations- Single unit  Cyclically active (intrinsically active)  Cardiac and pacemaker cells- periodic action potentials  Subject to hormone and paracrine control as is all smooth muscle  Histamine= inflammation  Nitric Oxide= synthesized by endothelial cells and causes relaxation of blood vessels o Most do receive innervations o Bladder is stretch sensitive o Vascular smooth muscle is also stretch sensitive- maintenance of blood pressure  Regulation of [Ca2+]i in smooth muscle cells o Trigger for contraction o Where does calcium come from  Center is calcium



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