Answer:
Endocardium
Explanation:
The endocardium makes the innermost lining of the wall of the heart. It is present over the thin layer of connective tissue. The function of the endocardium is to provide a smooth lining for the chambers of the heart. The valves present in the heart also have endocardium. The dense connective tissue of the heart valves is covered by endocardium.
The presence of the smooth endocardium made up of endothelium reduces the surface friction as blood passes through the heart. The endocardium of heart chambers is continuous with the endothelial lining of the large blood vessels that are attached to the heart.
Answer:
WBC.
Explanation:
WBC have cells, hence the name White Blood CELLS. They also contain a nucleus.
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
That is where the fibers of the optic nerve exit the eye extending into the brain. there are no rods and cones there as a result.
