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