The Muscular System

Part II

Skeletal Muscle Contraction

Introduction

• Muscles receive…• Actin and myosin…• Sarcomeres…• Muscle fibers…• Pulls on…

Fig. 9.8

Neuromuscular Junction

• Each skeletal muscle fiber ___________ connected to a neuron

• Neurons (Motor Neurons)1. 2.3.

• Neurotransmitters1. 2. 3.4.

Neuromuscular Junction

• Synapse1.

2. • Ach receptors

1.

2.

Fig. 9.8

Fig. 9.9

Fig. 9.8

Stimulus for Contraction

• Muscle impulse1.

2.

Excitation Contraction Coupling

• Muscle impulse causes …• Ca2+ binds to …• Binding sites …• Actin can…

Fig. 9.10

The Sliding Filament Theory

• Sarcomeres…• Thin and thick filaments …• Slide past one another

1.

2.

3.

Fig. 9.11

Fig. 9.11

Cross-Bridge Cycling

• Sarcomere shortening1. 2. 3.

• ATP is required 1. 2.

• Cross- bridge binding repeats1. 2.

Fig. 9.10

Relaxation• Nerve impulse…• Acetylcholinesterase

1. 2.

• Calcium …• Myosin…• Tropomyosin … *ATP …

– Rigor mortis

Fig. 9.10

Diseases of the Muscular System

• Polio1.

2. • Botulism

1.

2.

Clin. App. 9.1: Myasthenia Gravis

1. 2. 3. Symptoms

a. b.

4. Treatmenta. b. c. d.