Unit 4: Cells, Tissues, Organs, and Systems

Everything and everyone ages. But scientists have made discoveries about our cells and circulatory and immune systems that could potentially one day be used to increase human lifespans.

The human eye lets us see the world by sending impulses to our nervous system. In many ways, it is very similar to other optical devices, including cameras.

Panic attacks are scary and they upset your body’s chemical equilibrium. Learn what happens to acids & bases in your circulatory system during a panic attack.

When fertilizers from agriculture get into lakes and rivers, big problems can result for aquatic ecosystems, food chains & webs!

Researchers have found that consuming foods rich in flavanols is linked to more efficient blood flow, which can improve brain function.

Microbes are everywhere, even in your digestive tract. Some of these microbes are helpful, and some aren’t.

Heavy metal is a term for some toxic chemical elements. They can cause problems like bioaccumulation, but are useful in nuclear medicine and medical imaging.

Learn the basics of how DNA can be extracted from cells.