Anatomy and Physiology Digestion and Absorption

Mastication Mechanical reduction of the ingested food particles Food is mixed with saliva forming a bolus Tongue (muscular organ) moves food around mouth to form and push bolus down esophagus

Tongue Taste buds – more discriminatory when food is in a native or unprocessed state (able to distinguish between harmful and proper foods)

Taste Buds Humans: – 5-6 types of taste buds: sour, bitter, salty, umami (meatiness) and sweet (possibly fat) – sweet receptor made up of two coupled proteins generated by two separate genes Tas1r2 and Tas1r3

Cats Can’t Taste Sweet Cats have about 470 taste buds lack 247 base pairs of the amino acids that make up the DNA of the Tas1r2 gene – does not code for the proper protein Why do you think it is a good thing that cats can’t taste sweet things?

Cats Can’t Taste Sweet cats can taste things humans cannot – ATP – signal for meat most major pet food manufacturers use corn or other grains in their meals – Cat food = ~20% carbohydrates – Is this causing diabetes in cats?

Cats Can’t Taste Sweet The suggestion that cats may have difficulty adapting to high-carbohydrate meals appears to be based on two observations: – (1) cats lack glucokinase, an enzyme used to phosphorylate glucose inside cells – (2) cats lack salivary amylase and, compared with dogs, may have lower activities of the enzymes involved in carbohydrate digestion

Cats Can’t Taste Sweet For glucose to be used by a cell, it must enter the cell and be phosphorylated by glucokinase Lacking glucokinase activity, cats rely on other enzymes, including hexokinase – less efficient than glucokinase when glucose concentrations are high, cats have considerably more hexokinase, phosphofructokinase and pyruvate kinase enzyme activities than dogs

Dogs Can’t Taste Salt Dogs have only about 1,700 taste buds that people (~10,000) do, and their distinct sense of taste is actually quite poor

Diseases of the Oral Cavity Oral Tumor: can arise from the bone, teeth or soft tissue structures of the lower (mandible) or upper (maxilla) jaw, or the tongue or pharynx

Oral Tumors most are malignant malignant melanoma and squamous cell carcinoma are the most common oral tumors in dogs squamous cell carcinoma is the most common oral tumor in cats

Oral Tumors Diagnosis – Physical exam – Blood tests – Aspiration – MRI – Chest X-rays Treatment – Surgery – Radiation – Chemotherapy

Periodontal Disease Preventable Shows up at 3-4 years of age Clinical Signs – Inflamed gums – Tartar build up – Loose teeth – Difficulty eating – Halitosis

Periodontal Disease Mainly caused by bacteria: Peptostreptococcus, Actinomyces, and Porphyromonas Treatment: – Dental cleaning (vet) – Brush teeth daily (home) – Diet (tartar contro, i.e. T/D) – Tooth extraction

Stomatitis Painful, inflammation of the mouth Potential to be fatal

Periodontal Disease Periodontal disease can lead to heart disease and kidney disease if left untreated