2. NERVE MUSCLE PHYSIOLOGY
Dr Farzana Salman

3. OBJECTIVES At the end of this discussion you should be able to:
1. Know the structural components of a muscle fiber
2. Differentiate striated muscles & correlate it with structural components.
3. Know the major types & functions of Proteins present in a muscle fiber

4. Types of Muscles Skeletal. Excitability. . Structure
Similarities Differences
Skeletal. Excitability Structure
Contractility Location
Cardiac. Elasticity Function
Activation
Smooth Contraction

5. Physiological anatomy of
MUSCLE
Muscle Fascicle

6. Physiological anatomy of
MUSCLE

9. “Structural and functional Unit of the Muscle”
S A R C O M E R E
“Structural and functional Unit of the Muscle”
Mainly Comprised of:
Actin Filaments
Arranged between two Z lines
Myosin Filaments
Besides these ?

11. SARCOPLASM
Spaces between the myofibrils are filled with intracellular fluid called sarcoplasm.
Potassium
Magnesium
Phosphate
Protein enzymes
Mitochondria

12. Sarcomere (Supportive Proteins)
1. Titin,
2. Actinin,
3. Desmin &
4. Dystrophin-Glycoprotein complex

16. SARCOMERE Proteins Titin: MW= 3 million Largest springy protein
Provides scaffolding for the sarcomere
Connects Z line to M line
Actinin : MW=190,000
Binds actin to Z line
Desmin: Binds Z line to plasma membrane

17. Dystrophin-Glycoprotein Complex
Large Protein, MW =
Forms a Rod which connects the Actin filament to the transmembrane Protein Beta-Dystroglycan in the sarcolema.
Function:
Adds strength to the muscle by providing a Scaffolding for the fibrils & connecting them to the Extra cellular Matrix

18. Dystrophin-Glycoprotein Complex
Merosin

19. CLINICAL SIGNIFICANCE
Muscular dystrophies.
Diseases that cause progressive weakness of skeletal muscle
1) Duchenne muscular dystrophy.
2) Becker muscular dystrophy.