Prehension, mastication, swallowing, and esophagus Flashcards
Facial muscles in herbivores vs. carnivores vs. omnivores
Herbivores: well developed
Carnivores:reduced, allowing wide mouth gape
Omnivores: reduced
Jaw motion in herbivores vs. carnivores vs. omnivores
Herbivores: no shear, more side to side and front to back action
Carnivores: shearing, minimal side to side
Omnivores:shearing, minimal side to side
Mouth opening in herbivores vs. carnivores vs. omnivores
Herbivores:small
Carnivores and Omnivores: large
Incisors in herbivores vs. carnivores vs. omnivores
Herbivores:broad, flat and spindle shaped
Carnivores:sharp and pointed
Omnivores: sharp and pointed
Canines in herbivores vs. carnivores vs. omnivores
Herbivores: short or long for defence or none
Carnivores and Omnivores: long, sharp, curved
Molars in herbivores vs. carnivores vs. omnivores
Herbivores: flattened with cusps
Carnivores: sharp, jagged, and blade shaped
Omnivores: sharp blades and or flattened
Prehension
-the seizing and conveying of food/liquid to the mouth
-methods vary between animals (domestic use lips, teeth and tongue; some animals will use forelimbs to hold food to pass into mouth)
Horse prehension
-horse uses its mobile lips extensively to prehend food
-while grazing these sensitive lips are drawn back to allow the incisor teeth to cut grass
Cattle and Sheep Prehension
-lips have limited movement relative to the horse
-tongue is main prehensile organ (long, rough, mobile)
>curves around herbage pulling It towards mouth
-pulled between the incisor teeth and dental pad and severed by movement of the head
Pig prehension
-naturally, pig digs up the ground with snout (rooting)
-once food is found, it is carried to mouth primarily by the action of the lower pointed tip
Carnivore prehension
-use teeth to capture prey
-limited use of lips
-toss and catch motion
Bird prehension
-a type of toss and catch although varies among species
Prehension and consumption
-prehension is correlated but not equal to consumption
>animals may move product into the mouth, but does not mean they will consume it
**higher palatability=consumption
Drinking
-divided into:
>suction through orifice or a tube (capillary action)
>use tongue (combo of muscular contractions and capillary action)
Pig drinking
-tongue extends into the liquid with the snout immersed
Dogs and cats drinking
-move fluid to the mouth using tongue
-tongue used to create a ladle and lifts up a column of water, drops head and closes mouth allowing water to move to back of cavity
>inability to tightly close lips means that they cannot form negative pressure required
-rapid and repeatedly
Cattle, pigs, horses drinking
-draw liquid into the mouth by suction that is created by inspiration and tongue contractions
Taste
-a group of sensations mediated by the chemosensory system located in the oral cavity
-typically 5 senses: sweet, salty, umami, sour, bitter (cats and chickens don’t taste sweet) present in all areas of tongue
Papillae
-present on tongue, epiglottic, soft palate
-each papillae contains thousands of organelles called taste buds
Taste buds
-each consists of 50-120 sensory cell that project microvilli that reach the mucous layer of the tongue
>each cell within a taste bud expresses one family of taste receptor (TR)
Papillae types
-circumvallate
-fungiform
-filiform
-foliate
Taste receptors
-transmembrane proteins
-binding of the ligand to the Taste receptor triggers an intercellular metabolic cascade followed by intercellular communication and then finally form synapses with sensory neurons
Animals with greatest # of taste buds from least to greatest
-chickens
-dog (some studies suggest dog greater than cat)
-cat
-man
-pig
-cow
Tongues role in prehension
-has bundles of muscles that run in all directions allowing for flexibility
-muscles attached to posterior tongue allowing retraction, protrusion, depression and elevation
What innervates the motor aspects of tongue?
-hypoglossal (CN XII) nerve