Answer:
The prolonged electrical depolarization of cardiac muscle cells -that occurs during contraction- is due primarily to the persistent influx of calcium ion
Explanation:
The action potential of the heart muscle is longer with respect to skeletal muscle (around 300 milliseconds), and this is due to the activity of calcium (Ca⁺⁺ ) in the intracellular compartment.
The initial depolarization of cardiac muscle fiber depends on the entry of sodium (Na⁺) into the cell. However, for the action potential to occur and be maintained, Ca⁺⁺ must increase its cytoplasmic levels, which depends on:
- The increase in intracellular sodium induces the release of Ca⁺⁺ from the sarcoplasmic reticulum.
- Calcium entry from the extracellular space through the voltage dependent Ca⁺⁺ channels.
- The entry of extracellular Ca⁺⁺ causes the release of more Ca⁺⁺ ions by the sarcoplasmic reticulum, further increasing its intracellular concentration.
This is how the ion that guarantees the duration of the action potential of the cardiac muscle cell is the Ca⁺⁺.
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Calcium, sodium and cardiac muscle cells brainly.com/question/4473795
Answer:
RANDOM MATING
Explanation:
random mating
The Hardy Weinberg principle of genetic equilibrium defines that gene and allelic frequencies will remain the same among the generations in an infinitely large interbreeding population. In this population the mating among the members of the population is random and no selection, migration and mutation will occur.
The correct option is B, that is, A FAMILY DONATES USED CLOTHING TO A SECOND HAND STORE.
Waste prevention has to do with the process and practice of reducing the amount of wastes products in order to produce a more sustainable environment. Waste prevention can also be called recycling. There are three types of waste prevention, these are primary, secondary and tertiary waste prevention / recycling.
Primary waste prevention refers to a situation in which the material to be disposed is not changed in anyway, before been reused. Such material can be given to friend or donated to a charity organization. The material is always used for the same purpose as the original use.
Secondary waste prevention involves some kind of modifications while tertiary waste prevention usually involves the use of chemicals and heat.
