Monogastric pt 4 Flashcards
What are the digestive phase motility patterns in the SI?
- Propulsive
- Non-propulsive
What is propulsive motility?
- Aboral mvmt
- Peristaltic
- Slow waves
- Travel short distances
What is non-propulsive motility?
- Segmentation results from localized contractions
- 3-4 cm long
- Mixing action
What are the phases of interdigestive phase motility?
I- duodenal to ileal slpw waves
III- trigger AP and peristaltic contractions
What drives inter-digestive phase motility?
Migrating motility complex (MMC)
What is the function of the colon?
- Water and electrolyte absorption
- Fermentation of unabsorbed organic matter
- Storage of feces
What does colonic motility facilitate?
Mixing and thereby optimizes colonic functions
Where do horses get their high levels of energy?
Through fermentation with a correlation between colon size / structure
What are structural specializations in the equine colon?
- Haustra
- Segmentation
What allows form such strong mixing in the colon?
Retropulsion in more proximal regions
What are pacemaker regions?
Can move to region in which mixing is required and are excitable arease that lead to motility
What processes are influenced by colonic motility?
- Absorption
- Fermentation
Where are the colonic pacemakers?
Dog- junction between transverse and descending colon segments
Horse- pelvic flexure
Describe the anal sphincters?
Internal and external.
Internal- circular smooth muscle. relaxation (PSNS) Contraction (SNS)
External- striated muscel controlled by pudendal nerve
What is in the crop in birds?
Under vagal control. Esophageal outpouching get mucous secretion and used as storage of food for young
What is the proventriculus?
Glandular stomach. Low volume. Food mixed with glandular secretion in preparation for gizzard
What is the ventriculus?
Muscular stomach (gizzard). Koilin lining and has advanced grinding function and has some retention of indigestible material. Has grit
Is there physical separation of gastric components in birds?
YES
Small intestine in birds?
Motility similar to mammals
Ceca in birds?
- Paired
- Urinary excretions
- Reabsorption of water and electrolytes
Colon and rectum in birds?
Reverse peristalsis of contents back to ceca. Urine and feces exit at the same hole (Cloaca)
What is the function of saliva?
- Lubrication
- Bactericidal
- Digestion
- Cooling
What type of saliva do animals have?
Hypotonic as it leaves the duct. Isotonic as a primary acinar secretion (ruminants have isotonic)
What are the three major types of salivary glands?
- Parotid
- Submaxilllary
- Sublingual
What type of secretions does the parotid have?
Serous
What type of secretion does submaxillary have?
Mixed
What type of secretions does sublingual have?
Mucous
How does serous acinar cells secrete fluid?
- Cl (2Cl K Na) and HCO3 secretion generates lumen negative potential
- Na paracellular transport
- Water follows
Fluid leaving is isotonic
How does saliva end up hypotonic?
- Na absorption (ENaC and Na/H exchanger)
- Cl reabsorption and HCO3 secretion
- K secretion
- NO water permeability
What is different about ruminant saliva?
- High in PO4, HCO3m abd pH in order to neutralize acidity from fermentation
- Impeding salivation results in acidosis
- Copious volumes
- Little ductal reabsorption
CNS regulation of saliva
- PSNS: VII and IX at cholinergic receptors
- SNS: beta receptors
