These animated videos show the anatomy of body parts and organ systems and how diseases and conditions affect them.
Allergens, like pollen, are nothing more than foreign plant antigens. When they get released into the air, you can see and hear the result.When allergens first encounter nasal tissue, sneezing is triggered. This is part of the body’s immune defense. Pollen allergens then encounter the plasma cells in the nose, which respond by producing antibodies. These antibodies attach to mast cells, which are white blood cells containing the chemical histamine. As more antibodies are produced, they cause the mast cells to release histamine, which produces allergy symptoms such as a stuffy and runny nose, sneezing, and watery eyes. These help to remove the invading pollen. Medications called antihistamines can be used to help relieve severe allergy symptoms.See on Source
A plaque is an abnormal cluster of protein fragments. Such clusters can be found between nerve cells in the brain of someone with Alzheimer. A microscope will also show damaged nerve cells. In them are tangles called neurofibrillary tangles. These consist of twisted strands of a different protein. Together, the plaque and tangles cause structural and chemical problems. It appears that Alzheimer disease causes parts of the brain that normally work together to disconnect..See on Source
A change in the heart’s normal electrical conduction system can result in an arrhythmia, or irregular heartbeat. An arrhythmia can be an abnormally slow heartbeat, or an abnormally fast heartbeat. In some cases, it can be fatal..See on Source
Atherosclerosis is a disease in which fatty material is deposited on the wall of an artery. Normally, the walls of an artery are smooth, allowing blood to flow unimpeded. However, if damage occurs to its inner lining, fat, cholesterol, platelets, and other substances may accumulate at a damaged section of the arterial wall. Eventually, the tissue builds up and a plaque is formed, narrowing the lumen of the artery. Where the narrowing is severe, there is a risk that the vessel can become blocked completely if a thrombus forms in the diseased segment.See on Source
Athetosis resulting from basal ganglia injury
Athetosis is a condition marked by constant writhing movements. It's often caused by injury to basal ganglia. These are structures found deep within the brain near its base. They help coordinate muscle movement. The basal ganglia are highlighted here.See on Source