Illustration of an inflammatory mucositis in the mouth, beginning stage. This is a secondary response to radiation treatment for cancer elsewhere in the head. It proceeds from mild redness and irritation to blisters, ulcers, necrotic patches, and gum erosion.

Illustration of an inflammatory mucositis in the mouth, severe mucositis, with its signature secondary inflammatory effect on the lips, tongue, and gums. This effect followed radiation treatment for cancer elsewhere in the head. It proceeds from mild redness and irritation to blisters, ulcers, necrotic patches, and gum erosion.

Illustration of an inflammatory mucositis in the mouth, severe mucositis, stage 2. This is a secondary response to radiation treatment for cancer elsewhere in the head. It proceeds from mild redness and irritation to blisters, ulcers, necrotic patches, and gum erosion.

Illustration of an inflammatory mucositis in the mouth, severe mucositis, stage 3. This is a secondary response to radiation treatment for cancer elsewhere in the head. It proceeds from mild redness and irritation to blisters, ulcers, necrotic patches, and gum erosion.

Illustration of an inflammatory mucositis in the mouth, severe mucositis, stage 4. This is a secondary response to radiation treatment for cancer elsewhere in the head. It proceeds from mild redness and irritation to blisters, ulcers, necrotic patches, and gum erosion.

Illustration of a tumor deprived of newly formed vascular perfusion by antiangiogenic therapy. The tumor is initially affected by necrosis at its core, the area furthest from any peripheral vasculature serving healthy tissue.

Antiplatelet drug therapy to reduce blood clot formation (thrombosis) that causes heart attack or stroke. Aggregation occurs when fibrinogen (blue) binds to activated GP IIb/IIIa receptors on adjoining platelets. Aspirin, clopidogrel, and ticlopidine block platelet activation and aggregation (right). GP IIb/IIIa inhibitors impair aggregation (pink, center).

Human pancreas with a detail of an islet of Langerhans showing alpha (yellow) and beta (pink) cells. The islets are clusters of endocrine cells in the pancreas. Beta cells secrete insulin to reduce high blood glucose (sugar) by stimulating carbohydrate metabolism. When blood sugar is too low, alpha cells secrete glucagon, raising blood sugar levels.

Illustration of Roux-en-Y gastric bypass surgery, a type of bariatric (obesity control) surgery.

Illustration of adjustable gastric banding, a type of bariatric (obesity control) surgery.

Illustration of vertical banded gastroplasty, a type of bariatric (obesity control) surgery.

Illustration of radio frequency catheter ablation in the heart and an electrocardiogram (ECG) chart in the background. The catheters use low-voltage, high-frequency electrical charges to destroy isolated cardiac tissue that is causing arrhythmia.

Human pancreas and a detail of an Islet of Langerhans showing alpha (yellow) and beta (pink) cells. The islets are clusters of endocrine cells in the pancreas. Beta cells secrete insulin to reduce high blood glucose (sugar) by stimulating carbohydrate metabolism. When blood sugar is too low, alpha cells secrete glucagon, raising blood sugar levels.

Illustration of a renal glomerulus with diabetic glomerulonephropathy. Shown are changes related to diabetic renal disease: hyaline degeneration of the arterioles, fibrin cap formation among the tuft capillaries, and nodular lesions in the intercapillary tissue of the glomerular tufts.

Illustration of a hyaluronic acid injection into the knee joint space. This treatment provides temporary relief from osteoarthritic pain.

Illustration of radio frequency catheter ablation of a kidney tumor (inset) and the anatomical location of the kidney (background). A multi-pronged, umbrella-like ablation catheter uses low-voltage, high-frequency electrical charges to destroy a tumor in the kidney parenchyma.

Illustration of hands grasping a living will, or advance directive for health care. A person signs a living will to request not to be kept alive by medical life support machines in the event of a terminal illness.

Illustration of a normal pelvis and ligaments.

Illustration of an "open book" pelvic fracture. One or more pelvic bones are severely fractured, and the anterior and some posterior pelvic ligaments have ruptured.

Illustration of a fetus in the uterus showing occult umbilical cord prolapse, the umbilical cord descends alongside (but not past) the fetus, constricting the umbilical vessels (blood supply).