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
A thrombus is a blood clot that may form when the blood flow of an artery or vein is restricted, when the lining of a blood vessel is damaged, or when another condition causes a dog to produce clots excessively. They can form in the heart or within blood vessels. It frequently causes obstruction to blood vessels at its site of origin. All or part of a clot may break off and be carried through the bloodstream as an embo
Heartworm disease is a potentially fatal, but preventable, infection caused by a worm parasite, Dirofilaria immitis. The organism is transmitted by mosquitoes, which carry the heartworm larvae (called microfilariae) from an infected animal host to a new animal host. Once the larvae arrive in a new host, they grow into adult worms in several months and live in the blood vessels that serve the heart and lungs. In advanced infections, the heartworms
Dogs can have a variety of cardiovascular diseases. The most common ones are discussed below.
Degenerative Valve Disease
Degenerative valve disease is the most common heart disease in dogs and accounts for about 75% of cardiovascular disease in this species. This disease is characterized by thickening of the heart valves. It most commonly affects the mitral or tricuspid valve. The disease is
Heart failure is not a specific disease or diagnosis. It is a syndrome in which severe dysfunction results in failure of the cardiovascular system to maintain adequate blood circulation. There are limited and specific mechanisms by which heart disease can result in failure of the cardiovascular system. Therefore, there are limited and specific signs that can develop as a result of heart failure.
Types of Heart Failure
Congenital abnormalities of the cardiovascular system are defects that are present at birth. They can occur as a result of genetic defects, environmental conditions, infections, poisoning, medication taken by the mother, or poor maternal nutrition. In some cases, it is a combination of these factors that causes the defect. For several defects, an inherited basis is suspected based on breed and breeding studies. However, some studies have suggested that fewer than 1%