The ear is an organ of hearing and an organ of balance. It consists of the outer, middle, and inner ear.
The outer ear includes the pinna (the part you see that is made of cartilage and covered by skin, fur, or hair) and the ear canal. The pinna is shaped to capture sound waves and funnel them through the ear canal to the eardrum. In dogs, the pinnae are mobile and can move independently of each other. The size an
Anal Sac Disease
Anal sac disease is caused by clogging or infection of glands called anal sacs located on each side of the anus. It is the most common disease of the anal region in dogs. The anal sacs are related to the scent glands in skunks and produce a small amount of foul-smelling liquid. The liquid is normally squeezed out during defecation. Small breeds are predisposed to anal sac disease; large or giant breeds are
The liver is an organ that performs numerous functions. It has a large storage capacity and functional reserve and is capable of regenerating. These properties provide some protection against permanent damage. However, the liver is also susceptible to injury because of its role in metabolizing, detoxifying, and storing various toxic compounds.
Signs that a dog has liver disease can vary and include loss of appetite, vomiting, stomach ulceration, diarrhea, sei
The pancreas is an organ that has 2 main functions: endocrine and exocrine. The endocrine pancreas produces the hormones insulin and glucagon, which regulate blood sugar levels. 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
Protozoa are single-celled organisms that can sometimes cause disease. They may be free-living or parasites. Some of the more common diseases caused by protozoa in dogs are discussed below.
Amebiasis
Amebiasis is a disease caused by the amoeba Entamoeba histolytica. It causes inflammation of the large intestine, which leads to persistent diarrhea. Amebiasis is common in tr
Many parasites can infect the digestive system of dogs ( see Table: Gastrointestinal Parasites of Dogs). The most common ones are described below. Some gastrointestinal parasites of dogs can also cause disease in people ( see Table: Gastrointestinal Parasites of Dogs and Cats That Also Infect People).
Table
Gastrointestinal
Certain bacteria may cause gastrointestinal disease in dogs. The most common of these are discussed below.
Campylobacter Infection
Gastrointestinal campylobacteriosis is a bacterial disease. It is caused by related bacteria of the Campylobacter and Arcobacter genera. These organisms, along with a number of o
Diseases that affect the stomach and intestines are common in dogs. They include infectious diseases such as bacterial, viral, and parasitic diseases and noninfectious disorders, such as tumors, bloat, and obstruction.
Canine Parvovirus
Canine parvovirus infection is a potentially fatal viral disease that most often affects puppies or unvaccinated adult dogs. The virus itself is resistant to a number of c
Vomiting is the forceful ejection of the contents (such as food, fluids, or debris) of the stomach and upper small intestine. It is typically preceded by other signs, such as nausea, excessive drooling, retching, and forceful contractions of the abdominal muscles and the diaphragm. Vomiting can be caused by many disorders, including digestive system disease, kidney or liver failure, pancreatitis, nervous system disorders, and ingestion of irritating substances and poisons.
Signs of problems with the esophagus include difficulty swallowing and regurgitation (return of food or liquid before it has reached the stomach). Regurgitation is effortless and has few warning signs, in contrast to vomiting which is an active process preceded by signs of nausea.
Congenital abnormalities of the esophagus (those present at birth) are discussed earlier in this chapter.
Disorders