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)