Medical illustration showing synaptic cleft with neurotransmitter.

T4 Bacteriophage injecting DNA into its bacterial host.

Illustration of breast cancer biopsy.

Medical illustration of the heart, with EKG lines superimposed on it. (c) Benedet

Blood clot.

Coronary thrombosis. Background: patient's recovery stages.

Stroke.

Illustration of the mechanism of a blood clot. This image shows Y-shaped antibodies (yellow), floating T-shaped antigens (gold), red blood cells (red), and a white blood cell (white). Antibodies bind to antigens as an immune response, causing agglutination of red blood cells (hemagglutination), which leads to blood clot formation.

Illustration of fiberoptic surgery on the colon, showing a polypectomy, the surgical removal of a polyp.

Gallstone removal from common duct by fiberoptic surgery.

Helicobacter pylori creating a stomach ulcer.

Pneumonia bronchitis.

Illustration depicting surgical infections.

Laser surgery.

Brain of teenage girl showing location of response to emotions of happiness and sadness.

Brain activated by pain.

Close-up of a brain with cerebral aneurysm.

Osteoarthritis of the femur.

Childhood arthritis.

Medical illustration of child with acute otitis media, an inner ear infection. Inset: otoscopic view of inflammed tympanic membrane.