What have we been learning??
• Types of Muscle• Muscle Structure• Muscle Stimulation
Types of Muscle
What are the 3 types of muscle?
Muscle Structure
Put these in order from outer to inner
• Connective Tissue– Perimysium– Fascia– Epimysium– Endomysium
• Muscle Groups– Fascicles– Muscle Fibers– Myofilaments– Myofibrils
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Muscle Structure
What is this?
Let’s look inside a myofibril
Inside a Myofibril
Muscle Stimulation
What’s the difference between motor unit & neuromuscular junction?
• Motor Unit: one neuron & the muscle fibers it controls
• Neuromuscular Junction: one neuron and one muscle fiber.
Let’s Label the Neuromuscular Junction
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Can a neuron contain muscle fibers??
• What are the circle like structures in the neuron?
• What is the muscle fiber in this picture?
Muscle Stimulation Process
1. Impulse travels down neuron
2. Once an impulse travels down the neuron, where does Calcium (Ca++) enter the neuron?– What does the Calcium
do?
Ca++
Muscle Stimulation Process
3. The neurotransmitters released from the vesicles do what?– Attach to muscle fiber
receptors
Muscle Stimulation Process
4. What is entering the muscle fiber?– Sodium (Na+)
Muscle Stimulation Process
5. What happens to the neurotransmitters after sodium enters the muscle cell?
- Travel back into vesicles
Muscle Stimulation Process
6. Muscle Impulse travels INSIDE muscle fiber to myofibril.
7. What is released from Sarcoplasmic Reticulum (SR)?
Calcium
Muscle Stimulation Process: Sliding Filament Theory
1. Ca++ released from SR attaches to what myofilament?
- actin
Muscle Stimulation Process: Sliding Filament Theory
2. Myosin heads attach to actin at binding sites
Muscle Stimulation Process: Sliding Filament Theory
3. Myosin pushes actin back (Walk along actin)