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biology : muscle fibres + its function

Explain how the structure of a muscle fibre is related to its specialised function

- It has mitochondria for aerobic respiration to supply energy.
- Has cell surface membrane
If it’s the cardiac muscles then here’s the explanation:

Cardiac muscle tissue, or myocardium, is a specialized type of muscle tissue that forms the heart. This muscle tissue, which contracts and releases involuntarily, is responsible for keeping the heart pumping blood around the body.The heart also contains specialized types of cardiac tissue containing “pacemaker” cells.
These contract and expand in response to electrical impulses from the nervous system.
Cardiac muscle cells also contain mitochondria, which many people call “the powerhouses of the cells.” These are organelles that convert oxygen and glucose into energy in the form of adenosine triphosphate (ATP).Cardiac muscle cells appear striated or striped under a microscope. These stripes occur due to alternating filaments that comprise myosin and actin proteins.
The dark stripes indicate thick filaments that comprise myosin proteins. The thin, lighter filaments contain actin.
When a cardiac muscle cell contracts, the myosin filament pulls the actin filaments toward each other, which causes the cell to shrink.
The cell uses ATP to power this contraction.
A single myosin filament connects to two actin filaments on either side. This forms a single unit of muscle tissue, called a sarcomere.
Intercalated discs connect cardiac muscle cells.
Gap junctions inside the intercalated discs relay electrical impulses from one cardiac muscle cell to another.
Desmosomes are other structures present within intercalated discs.
These help hold cardiac muscle fibres together
Original post by zarahh09
Explain how the structure of a muscle fibre is related to its specialised function

- It has mitochondria for aerobic respiration to supply energy.
- Has cell surface membrane

Skeletal muscles have focal innervation- so a muscle cell only synapses with one neurone. And one neurone innervates many muscle cells. An excess amount of acetylcholine is released every time to ensure a contraction happens. Skeletal cells have multiple nuclei and are large cells so they have no gap junctions. All muscles are made of actin and myosin which interacts to cause a contraction. In smooth muscle and cardiac muscles, actin is connected to Z lines- so a contraction can happen using the troponin tropomyosin complex. smooth muscle cells have no troponin tropomyosin complex to contract, and have dense bodies connected to actin. Skeletal muscle are large cells that extend across the length of the muscle and have multiple nuclei and no gap junctions, so you can have fine control of them by stimulating individual muscle fibres (because they're that big). Cardiac and smooth muscles are small and have a single nuclei. In skeletal muscles the preganglionic cells from the spinal cord which synapse onto the postganglionic cells release acetylcholine which stimulates the action potential to travel down the post ganglionic neurone, but in the sympathetic system that causes the post ganglion to release noradrenaline (binds to adrenoreceptors) but in parasympathetic system there is a release of acetylcholine (binds to muscarinic receptors) by the post ganglionic neurones when stimulated.

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