Excitation-contraction coupling Sliding filament mechanism independent studies by Huxley and Huxley (no relation) in 1954.

Slides:

Advertisements

Similar presentations

Advertisements

Skeletal Muscle Activity: Contraction

Neuromuscular Junction

Sliding Filament Theory

Depolarization Initially, this is a local electrical event called end plate potential Later, it ignites an action potential that spreads in all directions.

Destruction of Acetylcholine

Fig Myofibrils are surrounded by calcium- containing sarcoplasmic reticulum.

The Contraction Cycle Process Diagrams Step-by-Step Copyright © 2007 by John Wiley & Sons, Inc.

Sliding Filament Theory How do muscles work…... Muscle Cell Structure n Muscles are broken into smaller muscle fibers n muscle fibers are broken into.

Molecular Basis of Skeletal Muscle Contraction Dr.Mohammed Sharique Ahmed Quadri Assistant Professor Department Basic Medical Sciences Division of Physiology.

Muscle Function.

CONTRACTION OF SKELETLAL MUSCLE: SLIDING FILAMENT THEORY

The Steps of Muscle Contraction: The Sliding Filament Theory

Contraction of Skeletal Muscle Sliding filament theory of contraction (Excitation-Contraction Coupling)

Contraction of skeletal muscles

Unit V: Movement Muscle Contraction - Part I

Muscular system SKELETAL MUSCLE Skeletal muscle is made up of hundreds of muscle fibers –Fibers consists of threadlike myofibrils –Myofibrils composed.

Sliding Filament Mechanism

Warm-Up 4/8/15 1.What is an autoimmune disorder? 2.What how are LEMS and MG similar? 3.How are LEMS and MG different? Test - Tuesday.

09_10 Sliding filament theory Slide number: 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tropomyosin.

Skeletal Muscle Physiology cont. Diagram the chemical and mechanical steps in the cross-bridge cycle and explain the effect on the muscle fiber length.

Excitation-Contraction Coupling

Myofibrils are surrounded by calcium- containing sarcoplasmic reticulum.

Myofilaments: Banding Pattern

Muscle fiberMotor neuron Nucleus. SarcolemmaMyofibrils Sarcoplasmic reticulum (SR) T-tubule SR Cistern.

Sliding Filament Theory

Myosin Myosin is a protein molecule found in the thick filaments. Myosin is a protein molecule found in the thick filaments.

MUSCLE CONTRACTION. Microscopic Anatomy of Skeletal Muscle Sarcomere Contractile unit of a muscle fiber Figure 6.3b.

Chapter 9 Muscular System Part II.

Muscle Physiology.

Hair cells, actin bundles, and unconventional myosins.

Bundle of fibers Muscle fiber (muscle cell) Myofibril Sarcomere.

IN CLASS NOTES = STEPS OF A MUSCLE CONTRACTION. STEP 1 Calcium ions present Ca+ binds to troponin which makes tropomyosin move out of way for myosin head.

Molecular Basis of Skeletal Muscle Contraction

BGYB30 Midterm 2004 Total number of Marks available= 56 I will record all of the grades out of 54 total marks. Small adjustment of +0.5 for different markers.

Ch : Contraction and Metabolism of Skeletal Muscle

Exercise Science Section 3: The Muscular System An Introduction to Health and Physical Education Ted Temertzoglou Paul Challen ISBN

Muscle Physiology Dynamics of Muscle Contraction MMHS Anatomy.

The Sliding Filament Theory

Myosin heads cannot bind to actin filaments

Figure 10.6 Levels of Functional Organization in Skeletal Muscle Fiber

Molecular Basis of Muscle Contraction Mercedita Macalintal, MD, DPPS.

Molecular Basis of Muscle Contraction Standard 9 h. Students know the cellular and molecular basis of muscle ocntraction,including the roles of actin,

Muscle Contraction. 1.Acetylcholine (Ach) is released from the axon terminal (nerve) into the synaptic cleft and binds to Ach receptors in the sarcolemma.

Sarcomere Physiology: Sliding Filament Theory This is pretty exciting!

Neuron Function The Membrane Potential – Resting potential Excess negative charge inside the neuron Created and maintained by Na-K ion pump Copyright ©

Muscles and Muscle Tissue P A R T B. Depolarization Initially, this is a local electrical event called end plate potential Later, it ignites an action.

MECHANISM OF MUSCLE CONTRACTION AND RELAXATION. Muscle contraction Muscle contraction is accomplished by a sliding together or telescoping of the inter.

Muscle Contraction Chapter 9 Part B. How does the anatomical structure function physiologically? What is the importance of the membranes? Why is it important.

Muscles and Muscle Tissue

Muscle contraction.

Initially Sarcolemma is in the Resting Membrane state

Molecular mechanism of muscle contraction

Contraction of skeletal muscles

MUSCLE CONTRACTION © 2016 Paul Billiet ODWS.

Rigor is a transient state.

Introductory Skeletal Muscle – Histology Flash Cards

NOTES: The Muscular System (Ch 8, part 2)

Shortening of sarcomeres = muscle shortening

NOTES: The Muscular System (Ch 8, part 3)

Excitation-Contraction Coupling 1. Impulse arrives from motor neuron 2. Neuron releases acetylcholine (Ach) into synapse with muscle 3.

Skeletal muscle contraction

Contraction of skeletal muscles

Contraction II Department of Biology, WCU.

Sliding Filament Theory

Skeletal Muscle Fibers

Contraction of Skeletal Muscle

Presentation transcript:

Excitation-contraction coupling Sliding filament mechanism independent studies by Huxley and Huxley (no relation) in 1954

Excitation-Contraction contraction occurs when Ca 2+ binds with troponin C each cycle takes ~50 msec and sarcomere shortens ~10 nm contraction ceases when Ca 2+ is removed from sarcoplasm

ATP Hydrolysis: Overview in resting state, ATP is partially hydrolyzed myosin head binds to actin filament when binding becomes available ATP is completely hydrolyzed, and Pi and ADP are released from myosin head actomyosin complex is broken when ATP binds to myosin

Maintenance of [ATP] i myosin ATPase ATP + H 2 O ADP + Pi + H + creatine kinase creatine kinase PCr + ADP + H + Cr + ATP adenylate kinase ADP + ADP ATP + AMP

ATP Hydrolysis: Weak Binding Phase Transition 1 – A-M binding; ATP enters myosin ATP pocket Transition 2 – ATP weakens A-M complex, myosin detaches Transition 3 – ATP partially hydrolyzed Transition 4 – myosin weakly reattaches to next actin molecule

ATP Hydrolysis: Strong Binding Phase Transition 5 – Pi released from myosin ATP pocket; myosin cleft closes, strengthens binding Transition 6 – power stroke of myosin head Transition 7 – ADP released (rate-limiting step)

Transition 1 Transition 2 Transition 3 Transition 5 Transitions 6-7 Weak Binding Strong Binding