White blood cells are an important part of the body's immune system. They defend against certain bacteria, viruses, cancer cells, infectious diseases and other unwanted materials.
These blood cells float in a yellow liquid called blood plasma. Blood plasma is made up of 90% water and also contains various nutrients, electrolytes, gases, proteins, glucose and hormones.
The taste of food, is detected by sensory cells called taste buds located on top of the tongue. There are five basic tastes: sweet, bitter, sour, salty and savoury.
Red blood cells have the important job of carrying oxygen around the body. They also contain a protein called hemoglobin. Hemoglobin contains iron which combines with oxygen to give hemoglobin and our blood, a red color.
Some types of glial cells generate a substance called myelin that coat axons and work as electrical insulation to help them quickly and efficiently transmit signals.
Special color pigment cells under the skin called chromatophores allow some chameleon species to change their skin color, creating combined patterns of pink, blue, red, orange, green, black, brown, yellow and purple.
