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
Hormones are chemical messengers that have many different functions. The effects of hormones in the body are wide-ranging and varied. Some familiar examples of hormones include insulin, which is important in the development of diabetes, and estrogen and progesterone, which are involved in the female reproductive cycle.
The endocrine system consists of a group of tissues that release hormones into the bloods
Pet birds have an innate desire to try to hide any illness or injury. In the wild, showing signs of illness increases the chance they will be attacked by other animals. Thus, any behavior that is out of the ordinary is a sign that your bird may be ill. In particular, if you notice limping, the inability to move the wings properly, any unusual discharge, any changes in droppings, or a general lack of physical activity, you should seek veterinary advice or care promptl
As the average age of the pet bird has increased, so has the incidence of cancers and tumors. Avian cancers include most of the common locations and categories seen in other companion animals.
Internally, cancer may occur in the ovaries, testicles, kidneys, liver, stomach (often not identified until the bird has died), pancreas, intestines, heart, lungs, pituitary and thyroid glands, and muscles and bones. Both surgery and chemotherapy have been
A number of diseases may involve multiple parts or organ systems of a bird’s body. Signs can be general (such as weakness or lack of interest in food or activities) or more specific. Sometimes no signs are noted. The more common of these disorders are discussed here.
Polyomavirus
Polyomavirus was first identified in budgerigars (budgies), then in other parrots and parakeets, and most recently
Gout is the abnormal deposit of uric acid crystals in the body. Uric acid is produced by the liver and excreted through the kidneys. It is the white chalky material that appears normally in birds’ droppings. The uric acid, when not properly removed from the bloodstream, will begin to crystallize and collect in various places in the bird’s body. It is not toxic or harmful in itself, but the buildup of crystals can severely damage tissues.
G
Skin and feather disorders are among the most common health problems seen in pet birds. Loss of feathers and skin disorders can be signs of a local disorder (that is, one that only involves the skin or feathers), or they can be signs of general, system-wide disease.
Feather Cysts
Feather cysts occur when a growing feather is unable to protrude through the skin and curls within th