Topic 61 - Motility of the forestomachs, eructation, rumination

Question 1

Words to include in motility of the forestomach

Answer 1

• Light bolus
• Heavy bolus
• Gas pocket
• Reticular-rumen cycle
  
  • Reticular contraction
  • Resting
  • Ruminating
  • Erucating
  • Fermentation product
  • Density
  • Biphasic contraction
  • Reguritation
  • Mixing
• Omasal contraction

Question 2

Words to include in rumination

Answer 2

• Saliva
• Physiological pH
• Reflex mechanism
• Mechanoreceptors
• Ruminal mucosa
• Afferent fibers
  
  • N. vagus
  • Reflux
  • Myencephalon
  • Ventral area of hypothalamus
• Efferent fibers
  
  • Salivary glands
  • Esophagus
  • Reticulum
• Reguritation
• Remastication
• Redegutition

Question 3

Words to include in erucation

Answer 3

• Gas production
  
  • CO₂
  • Methane
• Stretch receptors
• Antiperistaltic gas transport
  
  • Esophagus
  • Pharynx
• Nasopharyngeal closure
• Alveolar air

Question 4

Words to include in motility of the omasum

Answer 4

• Water
• Electrolytes
• Suckling effect
• Suckling-pressure pump
• Reticulo-omasal opening

Question 5

Words to include in motility of abomasum

Answer 5

• Peristaltic wave
• Recurrent flow

Question 6

Words to include in innervation

Answer 6

• Parasympathetic
  
  • N. vagus
• Sympathetic
  
  • Plexus solearis

Question 7

Topics to include in the essay

Answer 7

1. General about light bolus and heavy bolus
2. Motility of the forestomach
   
   • Ruminoreticular cycle
     
     • Erucation
     • Rumination
3. Motility of omasum
   
   • The role of the reticulo-omasal opening
4. Motility of abomasum
5. Innervation of the forestomach

Question 8

How does the light bolus travel?

Answer 8

• Kept in dorsal sac of rumen for a longer period of time, until it becomes dense enough to sink down to the ventral sac
• Reticulum
• Omasum
• Abomasum

Question 9

How does the heavy bolus travel?

Answer 9

• Enters directly to the ventral sac, then the reticulum shortly
• Omasum
• Abomasum
• Microbial action happens in the rumen, so the light bolus food gets more exposed to it than the heavy

Question 10

Motility of the forestomach

General

Answer 10

• In ruminants, cyclic and spontaneous contraction occurs in the first three compartments of the stomach
• The motility of the compartments is divided into:
  
  • Reticular-rumen cycle
  • Omasal contraction
• Rumen contracts 6-8 times in 5 minutes

Question 11

Motility of the forestomach

Ruminoreticular cycle

Answer 11

• Types of activity:
  
  • Resting
  • Rumination
  • Erucation
• Role: separating the fermentation products according to their density, and mixing the forestomach content and transporting it to the abomasum
• The contraction starts in reticulum and spreads through rest of the rumen in a highly specific manner

1. Reticulum
   
   • Biphasic contraction
2. Cranial sac
   
   • Contraction inhibits flow between the cranial and caudal sacs
3. Caudodorsal sac
   
   • ​​Contraction pushes content to the ventral direction
   • Mixing begins
4. Ventral and caudoventral blind sac
   
   • ​​Mixing proceeds
5. Ventral sac
   
   • ​​Complete mixing
6. Erucation
7. Rumination

Question 12

Motility of the forestomach

Erucation

Answer 12

1. Gas production
   
   • Gas consists of CO₂ and methane
2. Gas location
   
   • On the top of the dorsal rumen sac
3. Gas enters cardia
   
   • Stretch receptors of the dorsal rumen sac are stimulated
   • Dorsal sac, cranial and caudal ruminal pillars contract and press the gas cranially
   • Reticulum dilates
4. Antiperistaltic gas transport in the esophagus
   
   • ​Cardia opens reflexively - the gas gets into the esophagus
   • Gas is passed towards the pharynx by antiperistalsis
5. Gas leaves the rumen
   
   • Nasopharyngeal closure
   • The gas can either:
     
     • Enter the lungs
       
       • Gas becomes balanced with the alveolar air
     • Emptied through nare
     • Enter the circulation

Question 13

Motility of the forestomach

Rumination

Answer 13

• Saliva secreted during rumination contribute to the normal amount of fluid and to the physiological pH of the reticulo-rumen
• Rumination is a reflex mechanism
  
  • Initiated by mechanoreceptors in the ruminal mucosa in reticulum and cardia
• Afferent fibers:
  
  • N. vagus
  • Run to the myencephalon and to the ventral area of the hypothalamus
• Efferent fibers innervate:
  
  • Salivary glands
  • Esophagus
  • Reticulum

1. Reguritation
   
   • Bolus enters into cardia-esophagus:
     
     • Saliva swallowing
     • Inspiration with closed glottis (Müller’s experiment)
     • Cardia opens reflexively
     • Regurgitation contraction
   • Esophageal phase:
     
     • Bolus squeezed
     • Bolus is separated and passed further by antiperistalsis
     • The bolus enters the oral cavity
2. Remastication
   
   • Remastication
   • Mixing with saliva
   • Swallowing with saliva (2-3 times)
3. Redegutition
   
   • Swallowing the remasticated bouls
   • Bolus is mixed in the rumen

Question 14

Innervation of the forestomach motility

Answer 14

• Parasympathetic:
  
  • N. vagus
  • Increases the intensity and frequency of the forestomach motility
• Sympathetic:
  
  • Plexus solearis
  • Decreases forestomach motility