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⁺⁺.
Learn more:
Calcium, sodium and cardiac muscle cells brainly.com/question/4473795
Most dietary <u>fats </u>are too large to be assimilated and absorbed into the capillaries but they are otherwise absorbed into the lacteals.
<h3>What are dietary fats?</h3>
Dietary fat is necessary for good health. It offers you strength and aids in the absorption of vitamins by your body. Dietary fat has about twice as much energy per gram as carbs and protein.
In the villi ( an organ in the small intestine) is located the lacteal which is a lymphatic capillary that absorbs and assimilates dietary fats.
Most nutrients are also absorbed through the blood capillaries, but as for dietary fats and fat-soluble vitamins, they are absorbed by the lacteals.
Learn more about dietary fats here:
brainly.com/question/988503
Isotonic solutions is the term used when the concentrations of solutes inside and outside a cell are in equilibrium.
Explanation:
The isotonic solution is one which have same osmotic pressure on either side of the semi-permeable membrane.
In the isotonic solution there will be free movement of only water molecules and not solutes.
isotonic solution is the solution when two solutions have equal solute concentration.
The concentration of the solution will be in equilibrium.
