E. coli--part of the normal flora of the human gut. Certain strains of E. coli produce various toxins that cause illness

Streptococcus pneumoniae, or pneumococcus

Helicobacter pylori. Coloured transmission electron micrograph (TEM) of a Helicobacter pylori bacterium (formerly known as Campylobacter pyloridis). Colonies of H.pylori occur on the stomach mucous membrane in people suffering gastritis, and this bacteria has been linked to stomach ulcer formation.

The human fungal pathogen Candida albicans alkalinizes the local extracellular environment.

In this image, human neutrophils are engulfing Streptococcus pyogenes cells through a process known as phagocytosis.

Developing nerve cells

Colorized low-temperature electron micrograph of a cluster of E. coli bacteria. Individual bacteria in this photo are oblong and coloured brown. As an alternative to using antibiotics for fighting E. coli infections in newborn and weaned pigs, scientists are finding promising results from introducing mixes of beneficial bacteria, obtained from other pigs, into the gut of young pigs.

human spinal nerve, SEM

E. coli bacteria, which under certain conditions can cause gastroenteritis and urinary tract infections. Some.strains also cause food poisoning. Magnification: x17,000

Art of Diatom algae (from Ernst Haeckel) B305/0177 Rights Managed Credit: MEHAU KULYK/SCIENCE PHOTO LIBRARY

Colored scanning electron micrograph (SEM) of squamous cell carcinoma (cancer) cells from a human mouth. The many blebs (lumps) and microvilli (small projections) on the cells' surfaces are typical of cancer cells.

Brain Cells

human intestinal flora

Most detailed model to date of Human Immunodeficiency Virus (HIV).....looks scary!

15 Beautiful Microscopic Images from inside the human body- This one : Sperm on the surface of a human egg - Environmentalgraffiti

Human embryonic stem cells

Staphylococcus aureus bacteria, the cause of a variety of human infections as well as food poisoning

Nerve cells, artwork

Staphylococcus aureus bacteria. Colored SEM of Staph aureus bacteria (yellow) on human nasal epithelial cells.

Human embryo

Schizophrenic brain cells created in the lab