Monogastric digestive system (Dog)

Monogastric digestive system (Dog)

1. MOUTH

   • teeth
     • 42 teeth
     • tear/shred meat
     • designed for biting off large chunks
     • feeding behaviours from ancestors
       • grey wolf
   • tongue
     • help push food toward oesophagus
     • aids swallowing
   • saliva
     • moistens food
       • aid swallowing
     • doesn't contain amylase
       • no digestion of starch/carbohydrate
     • mucous and watery saliva
   • no chemical processes
   • limited physical process

2. OESOPHAGUS

   • smooth muscular tube
   • move food from mouth to stomach
     • peristalsis
       • wave-like contractions to push food down
   • voluntary control
     • allow regurgitation
   • no digestion or absorption

3. stomach

   • layers
     • mucosa/lumen (inner layer)
       • mucous secretions
         • protect lining
       • gastric juice secretions
     • muscle layer
       • allow mechanical breakdown
         • through contractions
     • serosa
       • outer supportive layers
     • gastric folds
       • flatten when full
   • functions
     • mix foods with digestive juices
       • begin chemical and physical digestion
     • stores food for longer
       • bone dogestion
     • high acidic pH level (1-2)
       • kill harmful bacteria
       • digest bone
     • biological blender
   • secretions
     • secrete hydrochloric acid and pepsin
       • act on protein and bone
     • protein broken down to polypeptides
     • bone fragments are digested

4. LIVER, GALL BLADDER & PANCREAS

   • essential component
   • digest fat
   • PANCREAS
     • exocrine gland
       • secrete enzymes into dueodenum
         • proteases
         • lipases
         • amylases
     • endocrine gland
       • secrete hormones in blood
         • insulin
     • secretes bicarbonate salts
       • neutralise acidity of chyme

5. SMALL INTESTINE

   • narrow in diameter
   • 1.7-6 meters long
   • absorption of all nutrients
   • structure
     • Villi- finger like progections
       • larger surfaces area for absorption
     • long, winding structure
       • larger surface area for absorption
     • Duodenum
       • chyme
       • pancreatic juices
         • lipase
           • break down lipids
         • protease
           • break down protein
         • amylase
           • break down digestible carbohydrate
       • bicarbonate salts
       • bile salts
       • digestive enzymes from intestinal mucosa
     • Jejunum
       • absorption continues
     • ileum
       • some absorption of Vitamins and Minerals
       • remaining digesta now made of indigestible material
       • moves into large intestine through Ileo-caecal valve

6. LARGE INTESTINE

   • 3 sections
   • 0.3-1 metre
   • caecum
   • colon
     • Ascending
     • Transverse
     • Descending
   • rectum
   • function
     • absorb salt
     • absorb water
     • formation of faeces
     • intestinal flora
       • partially digest material to create short chain fatty acids
         • Acetate
         • Butyrate
         • Propionate
   • facts
     • total intestinal transit time= 12-30 hours
     • water content of well formed faeces= 65-75%
       • diarrhoea= 80-90% water

7. RECTUM

   • stores faeces

8. ANUS

   • expels faeces

9. HINDGUT FERMENTOR (HORSE)

   • Acid weaker than dogs
     • doesn't need to digest bone
   • produces bile from liver
     • no gallbladder
   • large caecum that's full of bacteria
     • helps fermentation of fibre
     • produces vitamin B complex and volatile fatty acids
   • large intestine absorbs Vitamin B and volatile fatty acids