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
The pair of structures that share the function of reabsorbing water into the body us the Hypothalamus and Pancreas.
Option C Habitat.... Polar bears are only found in the Arctic. The most important habitats for polar bears are the edges of pack ice where currents and wind interact, forming a continually melting and refreezing matrix of ice patches and leads (open spaces in the ocean between sea ice).
Answer:
The correct answer is - carbohydrates.
Explanation:
The four significant groups of macromolecules found in living beings are carbohydrates, lipids, nucleic acids, and proteins. carbohydrates comprised of carbon, hydrogen, and oxygen molecules, generally in a proportion of 1 : 2 : 1.
Living things use carbohydrates as their main form of energy. Carbohydrates are a class of macromolecules is essentially utilized as a quickly accessible energy source by living things.
Thus, the correct answer is - carbohydrates.
