VAN 211: Veterinary Histology and Embryology (2+2)

SPECIES DIFFERENCE

• Filiform Papillae: In ruminants the connective tissue core gives rise to several small secondary papillae, whereas the epithelial coat is raised into a single cornified one. In the horse, donkey and pig, the papillary core is an enlarged similar to papilla, from the top of which a cornified thread projects above the epithelial surface. In carnivores, the connective tissue core extends above the surface epithelium and bear papillae of unequal sizes.
• Fungiform papillae: Taste buds are very few in the Ox and horse. They are numerous in sheep, goat, pig etc.
• Cirvumvallate papillae: These bear numerous taste buds in pigs, and dogs and less so in cats. In the horse and pig, the taste buds are present over the entire papillary wall of the moat and are restricted to the bottom only in carnivores.
• Foliate papillae: Are absent in ruminants, rudimentary without taste buds in cats but are present in the horse, dog and rabbit.
• Taste buds: Those in the horse are melon-shaped and in Ox and Sheep they are Ovoid. In pigs, they are spindle-shaped and may extend into the tunica propria in the dog. They are more or less spherical in the cat and they are poorly defined.
• Lingual glands: Mixed glands are present in the margin of the tongue in the horse, in the root of the tongue in Ox and horse.
• In the horse, there is a fibrous cord in the middorsal region of the tongue located between the muscles. It is composed of fibrous and elastic tissue interspersed with fibrous and hyaline cartilage, fat and some striated muscle fibres, lingual muscles are inserted to it.
• In the dog there is Lyssa, a collagenous sheath enveloping adipose tissue.