The Lymphatic System
The lymphatic system removes excess fluid from body tissue and returns it to the bloodstream. At the same time, it cleans the fluid of microorganisms and other contaminants which can cause health problems. They are cleaned at places throughout the lymphatic system called lymph nodes. The lymph nodes are positioned in the body so that when certain muscles contract, the lymph vessels are squeezed, causing the lymph fluid (called interstitial fluid) travels through the lymph system.
In addition to the lymph nodes, the spleen tonsils, adenoids and thymus gland all work together as part of the immune system.
Sologratia Mom completed an interesting model of the immune system, using everyday materials "The kids made a model with some pompom yarn (lymph vessels/nodes), red pipe cleaner (circulatory system), white model magic (thymus), foam (spleen), foam disc (red blood cell) and a brown piece of paper. They labeled their parts when they were finished."
The cleaning power of lymph nodes comes from the white blood cells. The B-cells can be thought of as the archers who shoot their enemies with antibodies arrows from a distance. The T-cells, on the other hand, can be thought of as swordsmen who attack the enemies in hand-to-hand combat. Macrophage cells scavenge the lymph, eating bacteria and other debris. The B-cells produce memory B-cells in order to keep a memory of the infection so that it can react quickly if the body is attacked by the same infection again, which is why vaccines can work. (From Exploring Creation with General Science, Jay Wile)
Testing For Bacteria and Fungi
Where can bacteria and fungi be found? Does one place have more of them than others? To answer these questions, we decided to culture some bacteria and fungi ourselves. We set up some petri dishes and swiped different places to see which could culture bacteria and fungi the most easily.
For younger students, you can do a glitter germs demonstration instead. Just have your student rub some lotion on their hands. Then sprinkle some glitter on their hands. The glitter represents bacteria. Now have them do normal activities to demonstrate how bacteria is unknowingly passed as the glitter germs get spread.
What science studies have you been doing?
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