1. To thoroughly know what is normal and abnormal, pathologists must make the same slides of tissue over and over again. Through this experience, pathologists are able to recognize disease in the tissues of the body.

2. Cardiac Tissue Normal HeartMyocardial Infarction Two to three days after an MI, the myocytes show that they are irreversibly damaged. They've lost their nuclei. Leukocytes are present between the cardiac cells where damage has occured.

3. Leukemia Cancer of the bone marrow causes an increase in the numbers of leukocytes in the peripheral blood. Normal Blood SmearBlood Smear with cancer

4. Lungs The adult lung is characterized by alveoli with thin septal walls. Capillaries are numerous and become more prominent when the lung is congested. Microscopically, one sees greatly enlarged alveoli. For comparison, a few normal-sized alveoli are seen in the upper central portion of the photo. Emphysema

5. Squamous Cell Carcinoma (left) Light micrograph of normal squamous epithelial cells of the uterine cervix. (right) Light micrograph of a squamous epithelial carcinoma. Tumour cells, with large black nuclei and abundant, strongly stained cytoplasm, are clumped in the centre of the bottom image.

6. Skin Most warts are caused by the Human Papilloma Virus (HPV). This virus induces the epidermal cells into a rapid growth phase (hypertrophy). This is not, however, a cancerous process. It is usually self-limited, but can be treated by removing or killing the epidermal cells including the basal layer. Some strains of HPV, however, do cause cancer. Normal SkinWart

7. Skin Normal SkinMalignant Melanoma Cancer (or neoplasm) of the melanocytes as a result of sun exposure. Notice the thickened epidermis with extensions into the dermis. These cells will invade deeper tissues and metastisize to all parts of the body and eventually kill the sunbather.

8. Cerebral Hemorrhage These photos show cerebral hemorrhages in the brain of an 11 year old boy with HbSS. There were multiple hemorrhages throughout the brain. The high magnification photo on the right shows sickle cells.