CHARACTERISTICS OF SMOOTH MUSCLE body.pptx

physiology topic of smooth muscles in human body

1. CHARACTERISTICS OF SMOOTH MUSCLE ( Muscle Physiology )

2. DISTRIBUTION AND FUNCTIONS Non striated and involuntary Functions – Cardiovascular System Respiratory System Digestive system Renal System Reproductive System

3. STRUCTURE Fusiform or elongated shape Nucleus- single, central Well-defined Myofibrils and Sarcomere absent Myofilaments and contractile proteins Dense bodies Covered by connective tissue Tendons and aponeurosis - absent Sarcotubular network- T tubules absent and L Tubules poorly developed .

4. TYPES Single unit (Visceral SM) Multiunit Definition Cells work together Cells work independently Movement of cells Undergo co-ordinated movement Each cell moves and functions independently Gap Junctions Essential for transmission – vital for muscle activity Not essential Example GIT, Urinary System , etc Vascular

5. MUSCLE CONTRACTION

6. ELECTRICAL ACTIVITY ( Single unit) Resting Membrane Potential- Unstable( -50 to -75mV) Slow Wave Potential Action Potential – Spike Potential (A) Slow wave progression to spike (B) Action potential with Plateau (C)

7. ELECTRICAL ACTIVITY ( Multiunit) Nervous Stimuli – Neurotransmitters Depolarization ( Excitatory Junctional Potential) No Action potential Contraction

8. CONTROL OF SMOOTH MUSCLE

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