Type II reactions occur when an antibody binds to an antigen present at the surface of its own cells. These reactions can lead to several types of diseases in dogs, including anemia, blood clotting problems, and skin and muscle disorders. They may be associated with other immune system disturbances, such as systemic lupus erythematosus, or triggered by a drug, vaccine, or infection. Most often, the triggering cause cannot be pinpointed. Immune-mediated hemolytic anem
In a Type I reaction, the animal has been previously exposed to an antigen and produces an excess of antibodies. If this antigen appears in the blood, the reaction can be either body-wide (such as anaphylactic shock) or localized (such as itchy patches on the skin). If the antigen enters through the skin, a localized reaction is more common.
Anaphylactic Shock
Anaphylactic shock
The primary role of the immune system is to defend the body against foreign invaders or abnormal cells that invade or attack it. In order to do this, the immune system must distinguish between “self” and “non-self.” By recognizing invading microorganisms (such as viruses), chemical agents, or other foreign substances that are “non-self,” a body can protect itself from attack. Substances that stimulate an immune response in the body are called antigens. A
The immune system consists of a network of white blood cells, antibodies, and other substances that fight off infections and reject foreign proteins ( see Table: Specialized Cells and Molecules of the Immune System). In addition, the immune system includes several organs. Some, such as the thymus gland and the bone marrow, are the sites where white blood cells are produced. Others, including the spleen and lymph nodes, trap microorganisms and forei
Neuroendocrine tissues are tissues that have both nervous system and hormone-producing functions. They are found in a number of locations throughout the body. Tumors develop occasionally from neuroendocrine cells in the adrenal or thyroid glands, digestive tract, or pancreas. These tumors can be benign or malignant. Even if benign, a growing tumor can disrupt nearby normal tissues and, in some cases, secrete excess hormone.
Insulinomas
The thyroid gland is a 2-lobed gland in the neck. It produces iodine-containing hormones, the most important of which are T3 and T4 , which affect many processes in the body. In general, the thyroid hormones regulate metabolic rate, or the speed at which body processes “run.” Too little hormone causes body processes to be sluggish. Too much causes them to run too fast.
The secretion of thyroid h
The pituitary gland is located near the center and bottom of the brain. It produces a number of critical hormones that control many parts of the body, including several other endocrine glands. Because of this central role, it is sometimes called a “master gland.” Because large numbers of hormones are produced by the pituitary gland, a variety of different conditions can be caused by pituitary disease or tumors. The specific illness and signs depend on the cause and t
The way in which the body processes calcium and phosphate, the function of vitamin D (which acts more like a hormone than a vitamin), and the formation of bone are all tied together into a system that involves 2 other hormones—parathyroid hormone and calcitonin—that are secreted by the parathyroid and thyroid glands.
Disorders of calcium and phosphorus metabolism that affect the skeletal system are discussed in the chapter on bone, joint, and mus
The pancreas is composed of several types of cells that have distinct functions involved in the production of hormones and digestive enzymes. The exocrine pancreas produces enzymes that are essential for the digestion of complex dietary components such as proteins, triglycerides, and complex carbohydrates. The exocrine pancreas also secretes large amounts of bicarbonate, which buffers stomach acid. Disorders of the exocrine pancreas a
The adrenal glands are located just in front of the kidneys. The adrenal gland has 2 parts—the cortex and the medulla.
The adrenal cortex is subdivided into 3 layers, and each layer produces a different set of steroid hormones. The outer layer produces the mineralocorticoids, which help to control the body’s balance of sodium and potassium salts. The middle layer produces glucocorticoids, which are involved in met