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Obstructive lung diseases include conditions that make it hard to exhale all the air in the lungs. People with restrictive lung disease have difficulty fully expanding their lungs with air. Obstructive and restrictive lung disease share the same main symptom: shortness of breath with exertion.
A meningioma is a tumor that arises from the meninges — the membranes that surround your brain and spinal cord. Most meningiomas are noncancerous (benign), though rarely a meningioma may be cancerous (malignant). Some meningiomas are classified as atypical, meaning they're neither benign nor malignant but, rather, something in between.
A brain (cerebral) aneurysm is a bulging, weak area in the wall of an artery that supplies blood to the brain. In most cases, a brain aneurysm causes no symptoms and goes unnoticed. In rare cases, the brain aneurysm ruptures, releasing blood into the skull and causing a stroke. When a brain aneurysm ruptures, the result is called a subarachnoid hemorrhage. Depending on the severity of the hemorrhage, brain damage or death may result. The most common location for brain aneurysms is in the network of blood vessels at the base of the brain called the circle of Willis. What causes a brain aneurysm? A person may inherit the tendency to form aneurysms, or aneurysms may develop because of hardening of the arteries (atherosclerosis) and aging. Some risk factors that can lead to brain aneurysms can be controlled, and others can't. The following risk factors may increase your risk for an aneurysm or, if you already have an aneurysm, may increase your risk of it rupturing: Family history. People who have a family history of brain aneurysms are more likely to have an aneurysm than those who don't. Previous aneurysm. People who have had a brain aneurysm are more likely to have another. Gender. Women are more likely to develop a brain aneurysm or to suffer a subarachnoid hemorrhage. Race. African Americans are more likely than whites to have a subarachnoid hemorrhage. High blood pressure. The risk of subarachnoid hemorrhage is greater in people who have a history of high blood pressure. Smoking. In addition to being a cause of high blood pressure, the use of cigarettes may greatly increase the chances of a brain aneurysm rupturing.
Peristalsis, involuntary movements of the longitudinal and circular muscles, primarily in the digestive tract but occasionally in other hollow tubes of the body, that occur in progressive wavelike contractions. Peristaltic waves occur in the esophagus, stomach, and intestines.
The heart weighs between 7 and 15 ounces (200 to 425 grams) and is a little larger than the size of your fist. By the end of a long life, a person's heart may have beat (expanded and contracted) more than 3.5 billion times. In fact, each day, the average heart beats 100,000 times, pumping about 2,000 gallons. Your heart is located between your lungs in the middle of your chest, behind and slightly to the left of your breastbone (sternum). A double-layered membrane called the pericardium surrounds your heart like a sac. The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body. The inner layer of the pericardium is attached to the heart muscle. A coating of fluid separates the two layers of membrane, letting the heart move as it beats. Your heart has 4 chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart. The left ventricle's chamber walls are only about a half-inch thick, but they have enough force to push blood through the aortic valve and into your body.
Knee pain can happen at any age, but some doctors say they're seeing more people with osteoarthritis who are still young and active.
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