1. Nerve MUSCLE PHYSIOLOGY

2. Molecular Mechanism Of Muscle Contraction
Sliding filament mechanism
Walk along theory
Ratchet theory

3. Walk Along Theory

4. Interaction B/W Actin & Myosin

5. Walk Along (Ratchet) Theory

6. Relaxed & Contracted

7. NEUROMUSCULAR JUNCTION

8. Motor Unit
Single Motor Neuron & all Muscle Fibers it innervates constitute a single Motor Unit.
α- motor N

9. NeuroMuscular Junction

10. Release of Acetylcholine

11. Ligand Gated Channel (Acetylcholine)
Closed
Open

12. Safety factor for transmission at the Neuromuscular junction.
Fatigue of Neuromuscular Junction

13. Myasthenia Gravis 1 in every 20,000 persons.
Antibodies against acetylcholine receptors.
Autoimmune disease.
Muscle paralysis ---- inability of neuromuscular junction to transmit enough signals .
Neostigmine ---- anticholinesterase drug.

14. Sarcoplasmic Reticulum T-Tubule & Longitudinal Tubule

17. Sarcoplasmic Reticulum T-Tubule & Longitudinal Tubule

22. Sarcoplasmic Reticulum(T-tubule) DHP & Ryanidin Receptor (Hypothetical Model)

23. A.P entering the Sarcoplasmic Reticulum causing release of Ca++ ions

25. Excitation-Contraction coupling “The process by which the depolarization of the muscle fiber initiates contraction”

26. Sequence of Events in contraction of Muscle
Stimulation of Motor Neuron.
Release of neurotransmitter (Acetylcholine)
at Motor End-plate.
Binding of Ach to Nicotinic Receptors.
Increased Na+ conductance through Ach Channels
Generation of end-plate potential
Generation of Action Potential in Muscle Fiber

27. Sequence of Events in Contraction
Inward spread of depolarization along T-Tubule- Sensing by DHP receptors & opening of Rayanidine receptors in terminal cisterns.
Release of Ca++ from terminal cistern of Sarcoplasmic Reticulum and diffusion to myofilaments
Binding of Ca++ to Troponin-C, uncovering Myosin binding on Actin filaments
Formation of Cross linkages between Actin & Myosin leading to sliding of thin on thick filaments, producing movement of Z-lines toward the centre

28. Steps involved in Relaxation of Muscle
ATP attaches to Myosin head
Ca++ Pumped Back in Sarcoplasmic Reticulum.
(Ca++ Mg++ ATPase Pump always On )
Release of Ca++ from Troponin
Cessation of Interaction between Actin & Myosin filaments