Well , the humans have a closed double circulatory system as the blood passes by the heart twice per one cycle and doesn't leave the blood vessels like in insects.
》Pulmonary circulation : Blood is circulated to the lungs where it is oxygenated.
》Systemic circulation : Blood is circulated through all the other parts of the body where it unloads oxygen.
Oxygenated blood coming from the lungs enters the heart through the pulmonary vein which takes blood to the first chamber it meets ; the Left atrium. Left atrium pumps blood to the second chamber , which is left ventricle and during this time , the semi lunar valves are closed to prevent back flow of blood and the bicuspid valve will be open . Now , the left ventricle is filled with oxygenated blood so it will pump this blood to the whole body via the largest artery which is Aorta.
Oxygenated blood will unload oxygen to cells in need of it and will return back now to the heart as deoxygenated . This deoxygenated blood will enter the heart through superior and inferior vena cava which will take the blood to the third chamber , right atrium . Right atrium will pump blood to right ventricle so the semi lunar valves will be closed during this time and the tricuspid will remain open. Now that the fourth chamber is filled with deoxygenated blood , it will pump this blood through pulmonary artery when the semi lunar valves opens , to the lungs again to be oxygenated once more.
Notice that you have to know exactly the position of the valves that I have mentioned in the heart so that you could understand the blood flow better. You can refer to any heart labelled diagrams in your textbook or the internet.
Answer:
B. In plants, there are no sister chromatids.
It's the sodium ion.
When a neural impulse is fired in both neurons, it is always cause by an excited electron in one neuron moving to the other neuron to destabilize the balance of ions trying to keep them at equilibrium. This action either depolarizes or hyper-polarizes the membrane. If it does, then sodium ions--the key deficient ones--can flow into that region of low charge and maintain that state of low charge, keeping the cell membrane stable.
Answer:
A. Moon is between the Sun and Earth
Explanation:
The new moon stage is the faze in which we can not see the Moon from Earth. In this stage, the Moon is lacking from the sky, or rather we can not see it because it is totally dark from the side that is facing the Earth. The reason for this is that the Moon is located between the Sun and the Earth. The Sun is making half of the Moon bright as it always does, but in this stage it is the half of the Moon that is facing the Sun, while the other half that is facing the Earth is totally dark as it doesn't receive any sunlight at that time.
<span>Endoplasmic Reticulum
ER Golgi apparatus, because it packages proteins received from the ER cytoplasm </span>
<span>The Golgi body are the ones that slightly alter, organize and prepare so-called parcels to be delivered for all the organelles in the cell. They receive these packages mainly in the rough endoplasmic reticulum. These packages that set out by Golgi body are macromolecules that used and synthesized by cells in many operations. If ER is absent then it would only mean that Golgi body would have no use other than simply lysosomes but these macromolecules plays a dynamic role in many organelles –nutrients, ATP and cell metabolism. It'll have a ripple effect if ER is absent in the cell.<span>
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