Digestive Tract Musculature

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Digestive Tract Musculature

• Skeletal muscle - voluntary control
• Mouth, pharynx, cranial esophagus, ext anal
  sphincter
• Facilitates chewing, mixing saliva with food,
  initiation of swallowing, and control of
  defecation
• Smooth muscle
• Majority of esophagus, stomach, s. intestines, l.
  intestines, and internal anal sphincter
• Primarily arranged in circular and longitudinal
  layers
• Contraction of circular muscle fibers __________
  tract
• Contraction of longitudinal fibers __________
  tract

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Peristalsis

• Circular muscle contractions
• Wavelike movement along tract
• ________ contents along digestive tract

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Segmental Contractions

• Periodic circular muscle contractions
• Occur in different adjacent sites
• _______ digestive tract contents and slows their
  movement through tract

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• Salivary glands - saliva helps with evaporative
  _________, __________, and ___________ usually
  three pairs with ducts to oral cavity
• _________ salivary glands - ventral to ear canals
• __________salivary glands - ventral to parotid
  glands at the caudal angle of the mandible
• ____________ salivary glands - medial to the
  shafts of the mandible just under the base of the
  tongue

SALIVARY GLANDS
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Parotid salivary glands Mandibular salivary
glands Sublingual salivary glands Buccal salivary
glands
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Teeth

• Incisors, Canines, Premolars, and Molars are
  found in both herbivores and carnivores
• _______________ - chewing physically break down
  food into smaller pieces
• Increases the surface area of the food that is
  exposed to digestive processes
• _________ arcade - in maxilla and incisive bones
• _________ arcade - in mandible

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Teeth Surfaces

• ________ (tongue)- inner surface of lower arcade
• ________ (hard palate)- inner surface of upper
  arcade
• ________ (lips)- outer surface of upper/lower
  arcades (rostral)
• ________ (cheek) - outer surface of teeth
  (caudal)
• ________ surface that grinds with other teeth

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Teeth Shape

• Carnivore teeth - _________ on occlusal surface
  slightly curved toward back of mouth
• Good for holding prey, tearing, cutting,
  shredding
• Herbivore teeth - ________ occlusal surfaces
• Good for grinding plant and grain material

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Carnivore
Herbivore
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Types of Teeth

• Incisors
• _____________ teeth
• Most rostral teeth of upper
• and lower arcade
• Canines
• _____________ teeth
• Located at corners of incisors
• Longer than other teeth
• Pointed at tip

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Types of Teeth

• Premolars
• _____________ teeth
• Rostral cheek teeth
• Sharp points and surfaces
• in carnivores
• Molars
• ____________ teeth
• Caudal cheek teeth
• Larger, flatter occlusal surfaces

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Dental Formula

• Typical number of each type of tooth found in
  upper/lower arcades
• Tooth types in formula Iincisor, Ccanine, P
  premolar, Mmolar
• __________ case adult teeth
• __________ case deciduous teeth

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Dental Formula
Ruminants have no incisors or canines in their
upper arcade! _________ ______ - flat thick
connective-tissue on maxilla opposite lower
incisors and canines
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Dental Formulas for Several Domestic Species
Species Dental Formula Total
Number of Teeth Canine
- puppy i3/3 c1/1 p3/3 28 Canine -
adult I3/3 C1/1 P4/4 M2/3 42 Feline -
kitten i3/3 c1/1 p3/2 26 Feline - adult I3/3
C1/1 P3/2 M1/1 30 Equine - adult I3/3 C1/1
P3-4/3 M3/3 40 or 42 Porcine - adult I3/3 C1/1
P4/4 M3/3 44 Bovine - adult I0/3 C0/1 P3/3
M3/3 32

• Tooth type followed by two numbers separated by
  slash mark
• First number - teeth in half of upper arcade
• Second number - teeth in half of lower arcade
• Total number sum of all numbers x 2

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• Dogs 1st Molar in lower arcade and 4th Premolar
  in upper arcade
• Abscesses that form at the root of the apex of
  the upper carnassial tooth often break through
  the thin bone of the maxilla and begin to drain
  through the skin below the eye.
• Removing the carnassial teeth is difficult due to
  their deeply entrenched roots

Carnassial Teeth
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• Teeth are living structures that have nerve,
  blood vessel and lymphatic supply, making them
  susceptible to damage and pain.
• _____________ tooth above gums
• _____________ tooth below gums
• _____________ - center of tooth
• Blood and nerve supply enter at apex of tooth
  root
• ______________- surrounds and protects tooth
  pulp
• ______________- hard conn. tissue
• Covers tooth root
• Fasten tooth in bony socket
• ______________- covers crown
• Hardest, toughest tissue in body
• ______________ gums epithelial tissue around
  teeth

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Dental Prophylaxis

• Small animals- scaling away of tartar from the
  teeth.
• Dental __________
• Horses- teeth are ___________, which reduces
  points on buccal and lingual edges of teeth.

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Functions of the Oral Cavity

• Prehend food
• Initiate mastication (mechanical digestion)
• Breaks food into smaller particles
• Increases surface area for chemical digestion
• Crushed ice melts faster than single ice cube
• Initiate chemical digestion
• Saliva contains amylase, lipase
• Cow produces 25-50 gal/d (waste basket5 gal)
• Prepare food for swallowing

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• Digestive enzymes
• Proteins that promote the chemical reactions that
  split complex food molecules up into simpler
  compounds.
• Usually end in _______
• ________
• Found in saliva of omnivores but absent in
  carnivores
• Breaks down amylose- a sugar component of starch.
  
• ________
• Digests lipids
• Found in saliva of young animals while nursing or
  on high milk diet.
• Buffers
• Sodium bicarbonate and phosphate buffers found in
  saliva of cattle
• Neutralize acids normally formed in rumen
• Monogastric stomach pH2-3
• Ideal rumen pH 5.8-6.4

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Nervous System and Salivation

• Autonomic nervous system controls most digestive
  glands
• Parasympathetic ___________ salivation
• Anticipation of eating stimulates salivation
  (Pavlov)
• Sympathetic _____________ salivation and activity
  of other digestive organs
• Fear produces produce dry mouth