This document provides an overview of myology, the study of muscle structure and function. It defines key terms like myocyte, muscle fiber, fascicle, and sarcolemma. Muscle tissue is made up of myocytes, contractile proteins like actin and myosin, and structural proteins. The structure of muscle fibers is also described, including that they are composed of myofibrils containing thick myofilaments of myosin and thin myofilaments of actin. Contractile and structural proteins important for muscle contraction and structure are identified.

1. Myology
Dr. Radhika Chintamani
Asst. Professor
OMT

2.  Definition of myology
 Contents of myology
 Definition of muscle, myocyte, muscle fibril, muscle fiber
 Structure of muscle, myocyte
 Orientation of muscle fiber
Contents

3. Myology: study of structure, arrangement and action of muscle tissue.
 Its not only the study of muscle tissue, but also, the contents that its
made up of and fascia covering it.
 Muscle tissue is made up of myocytes, contractile proteins,
structural protiens, contractile unit, motor unit and muscle fibers.
Myology

4.  Myocyte: muscle cell.
 Muscle fiber: strands of fibers made up of myocyte arranged in
series.
 Fascicle: group of muscle fibers surrounded by a connective tissue.

5.  Fascia: covering of muscle.
 Sarcolemma: covering of muscle fiber
(muscle cell).
 Muscle fiber is made up of number of
myofibril.
 Fascicle: group of muscle fibers.
STRUCTURE OF MUSCLE FIBER

6.  Basically two types: contractile and structural.
 Contractile proteins: help in muscle contraction, which are actin,
myosin, troponin and tropomyosin.
 Structural proteins: help in maintenance of structure of muscle,
which are intermediate filaments, desmin and titin.
Proteins of Muscle

7.  Myofibril is composed of thick myofilaments of the protein Myosin
and thin myofilaments of the protein Actin.
 Myosin and Actin: Contractile proteins of muscle, whose interaction
is essential for muscle contraction.
A. Contractile Proteins: Myofilaments

8.  Contractile Protein structure.
 Thin filament
 String like strands. Each Actin is made up of 2 strands.
** Troponin: globular protein found in notches between actin strings.
** Tropomyosin: protein attached to each troponin molecule.
Both the above mentioned molecules are important in muscle contraction.
Actin

9.  Thick myofilament.
 Contractile Protein structure.
 Head groups: a globular enlargements on myosin molecule, able to
swivel and have attachment site to the actin.
Myosin

10.  Help in maintenance of structure of muscle.
 Intermediate filaments: provides structural scaffold to the muscle fiber.
 Desmin: involved in the transmission of force along the fiber and to
adjoining fibers.
 Titin: maintaining the position of thick filament during muscle
contraction.
B. Structural Proteins

11.  Called so because of alteration of actin and Myosin which looks
like a striated pattern on miscroscopic view.
Diagram of sarcomere: a contractile unit of muscle
Striated Muscle

12. How muscle contract???