Motility & secretion of the GIT

Question 1

4 functions of motility?

Answer 1

Propel
Retain
Breakdown
Circulate

Question 2

Mastication involves…?

Answer 2

1st act of digestion
Mechanical breakdown
Moistens/lubricates
Abnormal teeth common cause of GIT disturbances

Question 3

Pharyngeal phase involves…?

Answer 3

Breathing stops momentarily -> soft palate closes nasopharynx -> tongue closes pharynx opening -> epiglottis folds over glottis -> closes laryngeal opening

Question 4

Motility in the proximal stomach…?

Answer 4

Food storage
Little mixing
Wall relaxes to accomodate meal
Then contracts -> push food & empty

Question 5

Motility in the distal stomach…?

Answer 5

Thick muscle
Vigorous contractions
Grinding, mixing 
Emptying function
Peristaltic waves push food -> pylorus

Question 6

2 primary patterns in SI motility…?

Answer 6

Propulsive - peristalsis

Segmentation - mixes digesta with digestive juices -> mucosal surface

Question 7

Describe the primary contractions (mixing) in the rumen

Answer 7

1st Reticulum contracts -> material to atrium & dorsal rumen
2nd contraction -> empties reticulum ->omasum
3. Rumen contractions cycles digesta round dorsal & ventral sac
4. Digesta moves back & forth -> ending up in omasum

Question 8

Secondary contractions in the rumen…?

Answer 8

Eructation
Produces CO2, O2, methane, nitrogen
Gases pushed cranially

Question 9

3 steps in rumination…?

Answer 9

Regurgitate - via reticular contractions & low pressure in thorax -> material into oesophagus -> antiperistalsis -> mouth
Remasticate - some matter -> resalivation
Reswallow

Question 10

Oral secretions from which glands?

Answer 10

Parotid
Mandibular
Sublingual

Question 11

2 types of saliva secretion?

Answer 11

Serous - parotids

Viscous - small glands

Question 12

Saliva contains…?

Answer 12

98% water
Mucin - lubrication
Amylase - Starch ->maltose (NOT in ruminants)
Bicarb
Lysozyme & antibodies - antibacterial
Urea - important N source for protein synthesis in ruminants

Question 13

Ruminant saliva vs monogastric…?

Answer 13

Ruminant - higher volume produced; higher pH; higher [bicarb], [phosphate] & [Na]

Question 14

Gastric secretion…?

Answer 14

Stomach lined with surface mucous cells
Protects stomach from acid
If injured -> stomach ulcers

Question 15

Gastric mucous properties?

Answer 15

From crypt & surface epithelial cells
Glycoproteins & mucopolysaccharides 
Protects against HCl & pepsin 
Barrier against bugs & endotoxins
Lubrication

Question 16

Pancreatic enzyme properties?

Answer 16

Secreted by EXOCRINE pancreas
2 types - potent enzymes & bicarb
Important in monogastrics (carry out most digestion)
Synthesised as zymogens (inactive)

Question 17

Main types of pancreatic enzymes…?

Answer 17

Proteolytic -> protein digestion
Pancreatic amylase & chitinase -> CHO digestion
Pancreatic lipase -> lipid digestion