ANP 1105 Lecture Notes - Lecture 13: Aldosterone, Arterial Tree, Vasoconstriction

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Balwant Tuana

Document Summary

Arrangement of fibres and microscopic structures of smooth muscle cells. The cells are separated by ne connective tissue; sheets of closely opposed bres; usually at least 2 sheets with opposite orientations. Alternating contractions of opposing layers provide mixing, peristalsis, and expelling. Instead of neuromuscular junctions, they are called, varicosities in smooth muscle cells; bulbous swellings of ans. It releases neurotransmitter into wide synaptic cleft near smooth muscle cells; diffuse junctions. Sarcoplasmic reticulum is less developed than in skeletal muscle; no t-tubules, but sarcoplasmic reticulum touches sarcolemma and smooth muscle cells have large sa/volume ratio. There are no striations, but do have interdigitating thick and thin laments: 1: tropomyosin, but no troponin (calmodulin instead), no sarcomeres: thick and thin laments spiral down smooth muscle cell, non-contractile intermediate laments and dense bodies(attach to thin laments). ratio of thick-thin=1:13 in smooth and 1:2 in skeletal. Electrical coupling via gap junctions slow, synchronized contractions.