Okay so an action potential from a neuron or something will release acetycholine (a neurotransmitter) into the space between the nerve and the muscle cell.
The acetycholine will bind to the receptors on the skeletal muscle cell membrane (sarcolemma) and this will depolarize the muscle cell. The Endoplasmic Reticulum (which stores calcium ions) will also depolarize opening channels which release Calcium into the cytoplasm (Sarcoplasm).
Okay so skeletal muscle cells or have functional units called sarcomeres which consist of thick and thin filaments.
The thin filaments are anchored at the end of the sarcomere to Z lines.
The thick filaments are intertwined among thin filaments.
(BTW on the side thick filaments produce dark bands that you can see of muscle cells and thin filaments form light bands)
The thick and thin filaments are made of myosin and actin protein respectively. And both of those proteins when they interact will slide along each other (called sliding filament mechanism).
However when a muscle is at rest, usually a protein Tropomyosin covers the sites (places) on the actin (thick filaments) where myosin will bind so that the muscle isn't always contracting.
When calcium is released into the sarcoplasm (cytoplasm) it will bind to troponin (another protein) which will pull the tropomyosin back uncovering the binding sites on the actin filament
Now myosin can bind to the actin and Using ATP it can slide along the actin filament pull the Z lines together and shorten the sarcomere.
A bunch of sarcomeres lined end to end form the myofibril and that's so a bunch of these sarcomeres (the functional unit of muscles) can contract an entire muscle.
Transverse tubules also are important because they help relay the signal deep into muscles and that causes all the sarcomeres to contract together making a stronger muscular contraction.
Remember calcium is usually NOT found in the cytoplasm in high concentrations. So tropomyosin will BLOCK myosin from binding to actin. And the muscle won't contract until something causes calcium to release into the cytoplasm
Okay so an action potential from a neuron or something will release acetycholine (a neurotransmitter) into the space between the nerve and the muscle cell.
The acetycholine will bind to the receptors on the skeletal muscle cell membrane (sarcolemma) and this will depolarize the muscle cell. The Endoplasmic Reticulum (which stores calcium ions) will also depolarize opening channels which release Calcium into the cytoplasm (Sarcoplasm).
Okay so skeletal muscle cells or have functional units called sarcomeres which consist of thick and thin filaments.
The thin filaments are anchored at the end of the sarcomere to Z lines.
The thick filaments are intertwined among thin filaments.
(BTW on the side thick filaments produce dark bands that you can see of muscle cells and thin filaments form light bands)
The thick and thin filaments are made of myosin and actin protein respectively. And both of those proteins when they interact will slide along each other (called sliding filament mechanism).
However when a muscle is at rest, usually a protein Tropomyosin covers the sites (places) on the actin (thick filaments) where myosin will bind so that the muscle isn't always contracting.
When calcium is released into the sarcoplasm (cytoplasm) it will bind to troponin (another protein) which will pull the tropomyosin back uncovering the binding sites on the actin filament
Now myosin can bind to the actin and Using ATP it can slide along the actin filament pull the Z lines together and shorten the sarcomere.
A bunch of sarcomeres lined end to end form the myofibril and that's so a bunch of these sarcomeres (the functional unit of muscles) can contract an entire muscle.
Transverse tubules also are important because they help relay the signal deep into muscles and that causes all the sarcomeres to contract together making a stronger muscular contraction.
Remember calcium is usually NOT found in the cytoplasm in high concentrations. So tropomyosin will BLOCK myosin from binding to actin. And the muscle won't contract until something causes calcium to release into the cytoplasm
Okay so an action potential from a neuron or something will release acetycholine (a neurotransmitter) into the space between the nerve and the muscle cell.
The acetycholine will bind to the receptors on the skeletal muscle cell membrane (sarcolemma) and this will depolarize the muscle cell. The Endoplasmic Reticulum (which stores calcium ions) will also depolarize opening channels which release Calcium into the cytoplasm (Sarcoplasm).
Okay so skeletal muscle cells or have functional units called sarcomeres which consist of thick and thin filaments.
The thin filaments are anchored at the end of the sarcomere to Z lines.
The thick filaments are intertwined among thin filaments.
(BTW on the side thick filaments produce dark bands that you can see of muscle cells and thin filaments form light bands)
The thick and thin filaments are made of myosin and actin protein respectively. And both of those proteins when they interact will slide along each other (called sliding filament mechanism).
However when a muscle is at rest, usually a protein Tropomyosin covers the sites (places) on the actin (thick filaments) where myosin will bind so that the muscle isn't always contracting.
When calcium is released into the sarcoplasm (cytoplasm) it will bind to troponin (another protein) which will pull the tropomyosin back uncovering the binding sites on the actin filament
Now myosin can bind to the actin and Using ATP it can slide along the actin filament pull the Z lines together and shorten the sarcomere.
A bunch of sarcomeres lined end to end form the myofibril and that's so a bunch of these sarcomeres (the functional unit of muscles) can contract an entire muscle.
Transverse tubules also are important because they help relay the signal deep into muscles and that causes all the sarcomeres to contract together making a stronger muscular contraction.
Remember calcium is usually NOT found in the cytoplasm in high concentrations. So tropomyosin will BLOCK myosin from binding to actin. And the muscle won't contract until something causes calcium to release into the cytoplasm
Okay so an action potential from a neuron or something will release acetycholine (a neurotransmitter) into the space between the nerve and the muscle cell.
The acetycholine will bind to the receptors on the skeletal muscle cell membrane (sarcolemma) and this will depolarize the muscle cell. The Endoplasmic Reticulum (which stores calcium ions) will also depolarize opening channels which release Calcium into the cytoplasm (Sarcoplasm).
Okay so skeletal muscle cells or have functional units called sarcomeres which consist of thick and thin filaments.
The thin filaments are anchored at the end of the sarcomere to Z lines.
The thick filaments are intertwined among thin filaments.
(BTW on the side thick filaments produce dark bands that you can see of muscle cells and thin filaments form light bands)
The thick and thin filaments are made of myosin and actin protein respectively. And both of those proteins when they interact will slide along each other (called sliding filament mechanism).
However when a muscle is at rest, usually a protein Tropomyosin covers the sites (places) on the actin (thick filaments) where myosin will bind so that the muscle isn't always contracting.
When calcium is released into the sarcoplasm (cytoplasm) it will bind to troponin (another protein) which will pull the tropomyosin back uncovering the binding sites on the actin filament
Now myosin can bind to the actin and Using ATP it can slide along the actin filament pull the Z lines together and shorten the sarcomere.
A bunch of sarcomeres lined end to end form the myofibril and that's so a bunch of these sarcomeres (the functional unit of muscles) can contract an entire muscle.
Transverse tubules also are important because they help relay the signal deep into muscles and that causes all the sarcomeres to contract together making a stronger muscular contraction.
Remember calcium is usually NOT found in the cytoplasm in high concentrations. So tropomyosin will BLOCK myosin from binding to actin. And the muscle won't contract until something causes calcium to release into the cytoplasm
Okay so an action potential from a neuron or something will release acetycholine (a neurotransmitter) into the space between the nerve and the muscle cell.
The acetycholine will bind to the receptors on the skeletal muscle cell membrane (sarcolemma) and this will depolarize the muscle cell. The Endoplasmic Reticulum (which stores calcium ions) will also depolarize opening channels which release Calcium into the cytoplasm (Sarcoplasm).
Okay so skeletal muscle cells or have functional units called sarcomeres which consist of thick and thin filaments.
The thin filaments are anchored at the end of the sarcomere to Z lines.
The thick filaments are intertwined among thin filaments.
(BTW on the side thick filaments produce dark bands that you can see of muscle cells and thin filaments form light bands)
The thick and thin filaments are made of myosin and actin protein respectively. And both of those proteins when they interact will slide along each other (called sliding filament mechanism).
However when a muscle is at rest, usually a protein Tropomyosin covers the sites (places) on the actin (thick filaments) where myosin will bind so that the muscle isn't always contracting.
When calcium is released into the sarcoplasm (cytoplasm) it will bind to troponin (another protein) which will pull the tropomyosin back uncovering the binding sites on the actin filament
Now myosin can bind to the actin and Using ATP it can slide along the actin filament pull the Z lines together and shorten the sarcomere.
A bunch of sarcomeres lined end to end form the myofibril and that's so a bunch of these sarcomeres (the functional unit of muscles) can contract an entire muscle.
Transverse tubules also are important because they help relay the signal deep into muscles and that causes all the sarcomeres to contract together making a stronger muscular contraction.
Remember calcium is usually NOT found in the cytoplasm in high concentrations. So tropomyosin will BLOCK myosin from binding to actin. And the muscle won't contract until something causes calcium to release into the cytoplasm
