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cells
The cells
lymphocyte
Mitochondria???
Nutrients and oxygen are carried to the cells of the body by the bloodstream. Nutrients are mostly transported by the circulatory system after being absorbed from the digestive system, while oxygen is carried by red blood cells through the process of respiration.
oxygen is carried in red blood cells
Oxygen is transferred to blood cells in the capillaries around the alveoli. It diffuses from the alveoli into the bloodstream, and to the hemoglobin molecule.
An end product of respiration, carbon dioxide is carried from cells to lung.
signals
OXYGEN
most human embryonic stem cells used for research come from unused IVF eggs. there are then strict regulations on how long these cells are allowed to grow for and what you are wllowed to do with them in the meantime and how you get ride of them when you are done, but these vary from country to country. there are other types of stem cells that are presnt in adults though (like hemopoatic (forgive my spelling) stem cells). much research has been carried out on these adult stem cells too. also, stem cells can be studied in living organisms (for example fruit flies or mice) and therefore come from (and are often not removed from) animals.
Memory cells, or T cells, are part of the immune system and carried in the blood stream. Due to the fact that they are carried in blood, the heart does help pump them, but it does not "have" memory cells of its own.
Arteries
diffusion
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oxygen