Shield volcanoes--the largest of all volcanoes on Earth (not counting flood basalt flows). The Hawaiian volcanoes are the most famous examples. These volcanoes are mostly made up of basalt, a type of lava that is very fluid when erupted. For this reason these volcanoes are not steep (you can't pile up a fluid that easily runs downhill).

Comedo (whiteheads or blackheads) or papules. The comedo is the basic acne lesion, which is a plugged pore. If the plugged pore stays under the skin, it's called a closed comedo and forms a white bump or whitehead. Blackheads are comedos that open up and appear blackish on the surface of the skin. This black color is not due to dirt, but because the air reacts with the excess oil. Nodules. These are more serious acne lesions. They lodge deeper in the skin, are painful, and can cause scarring. See similar questions...

See Special Events for a detailed description. A "regular" orienteering meet is point to point, take the controls in order, fastest person wins. A Score-o leaves the order up to the competitor. Controls have a point value. Most points in shortest time wins. A Night-o is just like regular Orienteering, it's just in the dark, and, yes, you bring a flashlight! See similar questions...

Unstable angina. People with coronary artery disease may develop unstable angina, meaning pain and discomfort can happen unpredictably, even during rest. The pain is generally more severe and frequent than that of chronic angina. New or more severe symptoms of unstable angina require medical help right away, since a heart attack may be about to happen. Chronic angina patients may develop unstable angina as their condition progresses. Syndrome X. See similar questions...

Diabetic retinopathy is classified as either nonproliferative (background) or proliferative. Nonproliferative retinopathy is the early stage, where small retinal blood vessels break and leak. In proliferative retinopathy, new blood vessels grow abnormally within the retina. This new growth can cause scarring or retinal detachment, which can lead to vision loss. The new blood vessels may also grow or bleed into the vitreous humor, the transparent gel filling the eyeball in front of the retina. See similar questions...

composed of a main lens and two reading ssegments; one for near and one for intermediate distances (about arm lengths) high power plus lenses used for cataract patients. - made with aspheric surfaces to minimise aberrations due to shape of the lens darken when exposed to short wavelength radiation (300nm - 400nm) or ultra-violet light - rate of darkening and final transmission of the lens (saturation transmission) depends on the ambient temperature. See similar questions...

All types respond differently to natural hormones occurring in different amounts in both men and women. Not all hair is visible on the surface of your skin. Hair growth goes between active and resting stages. On your head, above 90% of your hair is in the active growing stage that can last up to 7 years. The growing cycle of your body hair lasts only for a few months and as much as 30% of your hair is in the resting stage. See similar questions...

The two most prevalent types of migraine headache are migraines with aura and migraine without aura, the latter of the two being more common. See similar questions...

There are many different types of kidney stones. The vast majority of stones are composed of calcium. The most common types of stones are calcium oxalate (70%), calcium phosphate (5-10%), struvite (10%), uric acid (10%) and cystine (1%). It is not uncommon for a single stone to be made of more than one of these types. When this occurs, the stone is commonly referred to as a mixed stone. Less common types of kidney stones include Xanthine, DHA and crixivan stones. See similar questions...

Macular degeneration is classified as either dry or wet. The dry form is more common than the wet (about 90% of patients). It may result from the aging and thinning of macular tissues, depositing of pigment in the macula or a combination of the two. In the wet form, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes retinal cells to die and creates blind spots in central vision. See similar questions...

Strip Shingles -- these asphalt shingles are approximately three times as long as they are wide. Manufactured in both standard and metric dimensions, strip shingles are distinguished by the number of cutouts or tabs that they have. The most common type of strip shingle is the "three-tab" shingle. Different textural and lighting/shadowing effects can be achieved with strip shingles depending on the number, shape and alignment of the cutouts. See similar questions...

Stress incontinence occurs when you sneeze, cough, laugh, jog, or do other activities that put pressure on your bladder . It is the most common type of urinary incontinence in women. Urge incontinence, also called overactive bladder, occurs when the sensation to urinate is so strong that you cannot reach the toilet in time, even when your bladder contains only a small amount of urine. See similar questions...

Simple or chronic open-angle glaucoma: This accounts for the majority -- about 90 percent -- of cases. It progresses slowly and often goes unnoticed for many months or years, causing a gradual deterioration of vision. This type of glaucoma typically responds well to treatment. Therapy is usually continued for life so that the pressure is kept under control, helping to prevent loss of vision. In a few cases, surgery is required to allow the fluid to pass more freely from the eye. See similar questions...

There are many types of arrhythmias. They are identified by where they occur in the heart, in the atria or ventricles, and by the type of heart rhythm they provoke. When they originate in the atria, they are called atrial or supraventricular arrhythmias. Ventricular arrhythmias begin in the ventricles. Ventricular arrhythmias caused by heart disease are usually the most serious. See similar questions...

There are two basic types of trigger points, latent trigger points and active trigger points. Latent trigger points cause increased muscle tension, but don't produce pain unless they are physically compressed. Active trigger points are latent trigger points that have degraded due to muscle overuse or abuse, and are actively producing pain. See similar questions...

Yes. Urge incontinence results from an overactive bladder. The bladder is made of muscle and when that muscle contracts before the person is ready to urinate, incontinence results. Stress incontinence is leakage with coughing and activity and is not caused by a problem with the bladder at all. It results from weakness in the supporting tissues and muscles around the bladder and urethra. When a person has both kinds of leakage then the diagnosis is "mixed incontinence". See similar questions...

There are two kinds of oasis material available from floral suppliers - be SURE to obtain the right type! Oasis foam is made for both wet (watered) and dry floral arrangements. DO NOT USE "DRY" OASIS. Dry Oasis in made of a closed cell foam and used for arranging dry (and silk) flowers. It's slightly more durable, but will NOT absorb water. It will float for days without getting wet. :-( Wet Oasis is an open-celled foam, and very absorbent. See similar questions...

Abdominal Hysterectomy, which is performed by making a large incision in the lower abdomen and surgically removing the uterus. The tubes and ovaries can also be removed with this procedure, if indicated. Vaginal Hysterectomy, which is often indicated when the uterus is low in the pelvis. The surgeon enters the abdominal cavity through an incision in the vagina next to the cervix. The uterus is surgically removed through this incision. See similar questions...

There are different kinds of eye cancers. Below are some of the places near or on the eye where cancers can grow and the types that may be present on each one of these places: Eyelid tumors. Basal cell carcinoma is the most common type of eyelid cancer. It can be removed with surgery. Other types of eyelid tumors include squamous cell carcinoma, sebaceous cell carcinoma, and malignant melanoma. Tumors that grow on the surface of the eye (conjunctival tumors). See similar questions...