Course Hero Logo

B hormones and local factors such as lack of oxygen

Course Hero uses AI to attempt to automatically extract content from documents to surface to you and others so you can study better, e.g., in search results, to enrich docs, and more. This preview shows page 5 - 7 out of 9 pages.

b. Hormones and local factors, such as lack of oxygen, histamine, excesscarbon dioxide, or low pH, act as signals for contraction.3.Special Features of Smooth Muscle Contractiona. Smooth muscle initially contracts when stretched, but contraction isbrief, and then the cells relax to accommodate the stretch.b. Smooth muscle stretches more and generates more tension whenstretched than skeletal muscle.c. Hyperplasia, an increase in cell number through division, is possible inaddition to hypertrophy, an increase in individual cell size.C.Types of Smooth Muscle (p. 311)1.Single-unit smooth muscle, called visceral muscle, is the most commontype of smooth muscle. It contracts rhythmically as a unit, is electricallycoupled by gap junctions, and exhibits spontaneous action potentials.2.Multiunit smooth muscle is located in large airways to the lungs, largearteries, arrector pili muscles in hair follicles, and the iris of the eye. Itconsists of cells that are structurally independent of each other, has motorunits, and is capable of graded contractions.
IV.Developmental Aspects of Muscles (pp. 311–312; Fig. 9.30)A.Nearly all muscle tissue develops from specialized mesodermal cells calledmyoblasts (p. 311).B.Skeletal muscle fibers form through the fusion of several myoblasts, and areactively contracting by week 7 of fetal development (p. 311).C.Myoblasts of cardiac and smooth muscle do not fuse but form gap junctions ata very early stage (p. 312).D.Muscular development in infants is mostly reflexive at birth, and progresses ina head-to-toe and proximal-to-distal direction (p. 312).E.Women have relatively less muscle mass than men due to the effects of themale sex hormone testosterone, which accounts for the difference in strengthbetween the sexes (p. 312).F.Muscular dystrophy is one of the few disorders that muscles experience, andis characterized by atrophy and degeneration of muscle tissue. Enlargementof muscles is due to fat and connective tissue deposit (p. 312).Laboratory Correlations1. Marieb, E. N., and S. J. Mitchell.Human Anatomy & Physiology Laboratory Manual:Main Version. Eighth Edition Update. Benjamin Cummings, 2009.Exercise 14: Microscopic Anatomy and Organization of Skeletal MuscleExercise 16a: Skeletal Muscle PhysiologyPhysioEx™ 8.0Exercise 16b: Skeletal Muscle Physiology: Computer SimulationOnline Resources for StudentsmyA&P™The following shows the organization of the Chapter Guide page inmyA&P™.TheChapter Guide organizes all the chapter-specific online media resources for Chapter 9in one convenient location, with e-book links to each section of the textbook.Students can also accessA&P Flixanimations,MP3 Tutor Sessions, InteractivePhysiology®10-System Suite, Practice Anatomy Lab™ 2.0, PhysioEx™ 8.0,and muchmore.ObjectivesSection 9.1Overview of Muscle Tissues (pp. 276–277)A&P Flixanimation: The Neuromuscular JunctionA&P Flixanimation: Excitation-Contraction CouplingA&P Flixanimation: The Cross Bridge CycleA&P Flixanimation: The Resting Membrane PotentialA&P Flixanimation: Generation of an Action PotentialA&P Flix

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 9 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Fall
Professor
N/A
Tags

Newly uploaded documents

Show More

Newly uploaded documents

Show More

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture