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Chapter 11 Supplement 2Muscle Physiology
CARDIAC AND SMOOTH MUSCLE TISSUE
PowerPoint by John McGillSupplemental Notes by
Beth Wyatt
CARDIAC MUSCLE TISSUE LOCATION
Located in the Wall of the Heart
MAJOR FUNCTION Pumps Blood (By Contraction)
TYPE OF CONTROL Involuntary
Cardiac Muscle STRUCTURAL FEATURES
STRIATIONS Present (Striated)
Means Sarcomeres Present
NUCLEUS 1/Cell
Cardiac Muscle STRUCTURAL FEATURES
T TUBULES Present*
SARCOPLASMIC RETICULUM Present*
* NOTE: Though Both Are Present, Their Arrangement Is Different Than in SMF’s (Less Extensive; Ca++ In From Outside the Cell)
Cardiac Muscle SPECIAL FEATURES
INTERCALATED DISCS Junctions That Tightly Join Cardiac Muscle Fibers Lengthwise
BRANCHING Transverse Connections Between Fibers
Cardiac Muscle METHOD OF CONTRACTION
SYNCYTIUM Cardiac Muscle Tissue Contracts as a SYNCYTIUM (Unit of Combined Cells)
Due To Special Features (Intercalated Discs & Branching)(Creates a Continuous Sarcolemma)
Cardiac MuscleMETHOD OF CONTRACTION
SELF‑EXCITING (myogenic) Cardiac Muscle Tissue is Self‑Exciting
Doesn't Need Stimulation by Nerve Impulses
Stimulation Comes from Within the Tissue (Conduction System)
SMOOTH MUSCLE TISSUE
LOCATION Located in the Viscera
MAJOR FUNCTION Movement of a Substance Through the Hollow Organ (By Contraction)
i.e., Food through Digestive System
TYPE OF CONTROL Involuntary
SMOOTH MUSCLE TISSUESTRUCTURAL FEATURES
STRIATIONS Absent (Nonstriated, Smooth) Means Sarcomeres Absent Thick and Thin Myofilaments Are Present
Not Arranged in Sarcomeres (Not as Extensive) Arrangement of Thick and Thin Myofilaments Different
(Myofilaments Criss-cross and Attach to Sarcolemma)
SMOOTH MUSCLE TISSUESTRUCTURAL FEATURES
NUCLEUS 1/Cell
T TUBULES Absent
SARCOPLASMIC RETICULUM Present But Poorly Developed (Ca++ Comes In From Outside The Cell)
SMOOTH MUSCLE TISSUE
METHOD OF CONTRACTION
Method of Contraction Depends upon Type of Smooth Muscle Tissue VISCERAL (SINGLE UNIT): SYNCYTIUM/SELF‑EXCITING
Most Common Type of Smooth Muscle Tissue Contracts Like Cardiac Muscle Tissue
SMOOTH MUSCLE TISSUE
METHOD OF CONTRACTION Method of Contraction Depends upon Type of Smooth Muscle Tissue MULTI UNIT: INDIVIDUAL CONTRACTION/EXCITED BY NERVE IMPULSES
Contracts Like Skeletal Muscle Tissue (Motor Units Present)
Example: Arrector Pili Muscles