Transcript Chapter 11 Supplement 2 Muscle Physiology

Chapter 11 Supplement 2
Muscle Physiology
CARDIAC AND SMOOTH
MUSCLE TISSUE
PowerPoint by John McGill
Supplemental Notes by
Beth Wyatt
CARDIAC MUSCLE TISSUE

LOCATION


MAJOR FUNCTION


Located in the
Wall of the
Heart
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 Muscle
METHOD 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 TISSUE
STRUCTURAL 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 TISSUE
STRUCTURAL 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