The immune system is the body's defense against infectious organisms and other invaders. Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause disease.

Sleep apnea is a potentially serious sleep disorder in which breathing repeatedly stops and starts. You may have sleep apnea if you snore loudly, and you feel tired even after a full night's sleep. The main types of sleep apnea are: Obstructive sleep apnea, the more common form that occurs when throat muscles relax. Central sleep apnea, which occurs when your brain doesn't send proper signals to the muscles that control breathing. Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, occurs when someone has both obstructive sleep apnea and central sleep apnea. If you think you might have any form of sleep apnea, see your doctor. Treatment can ease your symptoms and may help prevent heart problems and other complications.

Neck pain is a common complaint. Neck muscles can be strained from poor posture — whether it's leaning over your computer or hunching over your workbench. Osteoarthritis also is a common cause of neck pain. Rarely, neck pain can be a symptom of a more serious problem. Seek medical care if your neck pain is accompanied by numbness or loss of strength in your arms or hands or if you have shooting pain into your shoulder or down your arm

Rupture of the Heart Wall and Mitral Valve Replacement

Lyme disease is a bacterial infection primarily transmitted by Ixodes ticks, also known as deer ticks, and on the West Coast, black-legged ticks. These tiny arachnids are typically found in wooded and grassy areas. Although people may think of Lyme as an East Coast disease, it is found throughout the United States, as well as in more than sixty other countries. The Centers for Disease Control and Prevention estimate that 300,000 people are diagnosed with Lyme disease in the US every year. That’s 1.5 times the number of women diagnosed with breast cancer, and six times the number of people diagnosed with HIV/AIDS each year in the US. However, because diagnosing Lyme can be difficult, many people who actually have Lyme may be misdiagnosed with other conditions. Many experts believe the true number of cases is much higher. Lyme disease affects people of all ages. The CDC notes that it is most common in children, older adults, and others such as firefighters and park rangers who spend time in outdoor activities and have higher exposure to ticks. LymeDisease.org has developed a Lyme disease symptom checklist to help you document your exposure to Lyme disease and common symptoms for your healthcare provider. You will receive a report that you can print out and take with you to your next doctor’s appointment.

Physiological & pathological breath sounds

This Video COPD, or chronic obstructive pulmonary (PULL-mun-ary) disease, is a progressive disease that makes it hard to breathe. "Progressive" means the disease gets worse over time. COPD can cause coughing that produces large amounts of mucus (a slimy substance), wheezing, shortness of breath, chest tightness, and other symptoms. Cigarette smoking is the leading cause of COPD. Most people who have COPD smoke or used to smoke. Long-term exposure to other lung irritants—such as air pollution, chemical fumes, or dust—also may contribute to COPD.

Slicosis is caused by inhalation of unbound (free) crystalline silica dust and is characterized by nodular pulmonary fibrosis. Chronic silicosis initially causes no symptoms or only mild dyspnea but over years can advance to involve most of the lung and cause dyspnea, hypoxemia, pulmonary hypertension, and respiratory impairment. Diagnosis is based on history and chest x-ray findings. No effective treatment exists except supportive care and, for severe cases, lung transplantation.

If a patient comes to you with a painful, throbbing, swollen, red face (a ''fat face'), perhaps with fever, trismus and lymphadenitis, he is probably suffering from an acute dental or oral infection, most probably an alveolar abscess. He may have: (1) An alveolar abscess begins as an infection in the bone around a non-vital infected tooth. He has severe pain, which becomes less as pus is released into more superficial tissues and his face starts to swell. After 36 hours of cellulitis he usually has a fluctuant abscess which needs draining. If drainage is delayed, the pus in his abscess discharges spontaneously through a sinus (26-8) in his gum or face, which may become chronic. First, control infection with antibiotics, and then drain the abscess, either by incising it where it is pointing, or by removing the infected tooth, which acts as a cork to prevent the pus escaping, or by doing both these things. If you remove a tooth before you have controlled the infection with antibiotics, and while his face is still severely swollen, you may spread the infection; your task will also be more difficult. (2) A periodontal abscess at the side of a tooth, caused by spread from an infected gum. (3) A pericoronal abscess caused by infection of the gum over the crown of an unerupted and impacted tooth, usually a lower third molar (''an infected wisdom tooth'). Often, an abscess does not form, and the gum round the tooth is merely inflamed.

Initial symptoms may include: Pain or discomfort in the upper tummy (abdomen), especially after eating. Indigestion. (Note: most people who have indigestion do not have stomach cancer.) Feeling sick, and being off food. ... Weight loss and/or loss of appetite. You may pass blood out with your stools (faeces).

The temporomandibular joint (TMJ), located just in front of the lower part of the ear, allows the lower jaw to move. The TMJ is a ball-and-socket joint, just like the hip or shoulder. When the mouth opens wide, the ball (called the condyle) comes out of the socket and moves forward, going back into place when the mouth closes. TMJ becomes dislocated when the condyle moves too far and gets stuck in front of a bony prominence called the articular eminence. The condyle can't move back into place. This happens most often when the ligaments that normally keep the condyle in place are somewhat loose, allowing the condyle to move beyond the articular eminence. The surrounding muscles often go into spasm and hold the condyle in the dislocated position.

Liver transplantation is surgery to remove a diseased or injured liver and replace it with a healthy whole liver or a segment of a liver from another person, called a donor. People with either acute or chronic liver failure may need a liver transplant to survive.

Though most snakes aren't venomous, the ones with a deadly bite are so scary that many researchers think humans evolved to naturally fear the sinuous creatures. With good reason. In the video, two men milk the venom of a Russell's viper and then show what happens when one drop of that venom mixes with a glassful of human blood. It's terrifying.

The occurrence and extent of cerebral infarction is determined by three basic factors: i) site of arterial occlusion, ii) the rapidity of arterial occlusion, and iii) the presence or absence of collateral circulation. Grossly, infarcts are usually divided into pale (non-hemorrhagic) and hemorrhagic types. Infarcts evolve over time, thus their gross appearance gives a clue to when they occurred. The temporal evolution of an infarct occurs in three stages: i) acute (1 day – 1 week) – the involved area is soft and edematous and there is a blurring of anatomic detail; ii) subacute (1 week – 1 month) – there is obvious tissue destruction and liquefactive necrosis of the involved brain; iii) chronic (>1 month) – the damaged tissue has been phagocytized and there is cavition with surrounding gliosis. Microscopically there is also a temporal evolution of cerebral infarcts. During the earliest phase of infarction (0-48 hours) chromatolysis and swollen eosinophilic neurons are seen. Neuronal cell necrosis and an acute inflammatory response are usually seen from 24-72 hours. This response is typically followed by an influx of mononuclear cells which begin to phagocytize necrotic debris (3-5 days). From 1-2 weeks after the infarct there is vascular proliferation and reactive astrocytosis. Over time (>1 month) the necrotic tissue will be completely removed and a cystic cavity surrounded by a glial scar will be formed.

This video: Tennis elbow or lateral epicondylitis is a condition in which the outer part of the elbow becomes sore and tender. The forearm muscles and tendons become damaged from overuse — repeating the same strenuous motions again and again.

When is endoscopy used? Endoscopes were first developed to look at parts of the body that couldn’t be seen any other way. This is still a common reason to use them, but endoscopy now has many other uses too. It’s often used in the prevention, early detection, diagnosis, staging, and treatment of cancer. To prevent and screen for cancer Some types of endoscopes are used to look for cancer in people who have no symptoms. For example, colonoscopy (KO-lun-AH-skuh-pee) and sigmoidoscopy (SIG-moid-AH-skuh-pee) are used to screen for colon and rectal cancer. These procedures can also help prevent cancer because they let doctors find and remove polyps (growths) that might become cancer if left alone. To find cancer early Endoscopy can sometimes be used to find cancer early, before it has had a chance to grow or spread. Looking for causes of symptoms When people go to the doctor with certain symptoms, endoscopy can sometimes be used to help find a cause. For instance: Laryngoscopy to look at the vocal cords in people with long-term hoarseness Upper endoscopy in people having trouble swallowing Colonoscopy in people with anemia (low red blood cell counts) with an unknown cause Colonoscopy in people with blood in their stool Looking at problems found on imaging tests Imaging tests such as x-rays and CT scans can sometimes show physical changes within the body. But these tests may only give information about the size, shape, and location of the problem. Doctors use endoscopes to see more details, like color and surface texture, when trying to find out what’s going on. Newer methods of endoscopy that include high magnification are being tested to find out whether they are more useful in detecting cancer and other abnormal cells on the inner surfaces of the body. To diagnose and find out the stage (extent) of cancer To get a tissue sample Going one step further, most types of endoscopes have tools on the end that the doctor can use to take out small tissue samples. This procedure is called a biopsy (BY-op-see). Samples can be taken from suspicious areas and then looked at under a microscope or tested in other ways to see if cancer is there. A biopsy is usually the best way to find out if a growth or change is cancer or something else. Getting a closer look In some cases endoscopes are used to help find out how far a cancer has spread. Thoracoscopy (THOR-uh-KAHS -kuh-pee) and laparoscopy (LAP-uh-RAHS-kuh-pee) can be very useful in finding out if cancer has spread into the thorax (chest) or abdomen (belly). The surgeon can look into these places making only a small incision (cut) in the skin.

Memory Loss & the Brain. It's not just a movement disorder. Besides causing tremors and other motion-related symptoms, Parkinson's disease affects memory, learning, and behavior. Parkinson's disease is notorious for so-called motor symptoms like muscle rigidity, tremor, slowed movement, and unsteady posture and gait.

The protein inside red blood cells (a) that carries oxygen to cells and carbon dioxide to the lungs is hemoglobin (b). Hemoglobin is made up of four symmetrical subunits and four heme groups. Iron associated with the heme binds oxygen.

A hormone is a chemical messenger that enables communication between cells. Hormones are secreted by the glands of the endocrine system and they serve to maintain homeostasis and to regulate numerous other systems and processes, including reproduction and development.

Ventral Hernia Repair