Download Document

• Single stomach
• Eat feed low in fiber
• Humans are also
non-ruminants
•
•
•
•
•
1.
2.
3.
4.
5.
Mouth
Esophagus
Stomach
Small Intestine
Large Intestine
• Breaks down
feedstuffs into …..
• simple chemical
parts…..
• so the pig can
absorb…..
• and utilize them .
• Breaks down feed
stuffs by chewing
• Adds saliva to help in
digestion
• Muscles contract to
move the food down
to the stomach
• Adds digestive juices to
break down food
The small intestine….
• Mixes secretions
• Absorbs nutrients
• Storage and formation
of feces
• Absorption of water
• Secretion and
reabsorption of
electrolytes
Non-ruminant
•
•
•
•
Abomasum- true stomach
depends on digestive enzymes
pepsin, rennin, trypsin, chymotrypsin, HCL
Needs
– energy (fat and CHO), protein (a.a.), minerals (Ca:P
1.2:1 to 1.5:1), vitamins, water, antibiotics and
other additives
Swine Gastrointestinal
Physiology
11/04
Digestive secretions: saliva
• Functions of saliva in non-ruminants:
– Lubricates food to facilitate swallowing
– Contains antibodies and lysozyme
– Some amylase in saliva of swine and rats, but
much less than in humans
• Functions of saliva in ruminants:
– Maintains fluid consistency of rumen
– Slightly alkaline; helps neutralize acids formed by
fermentation
– May help prevent frothing in rumen
Gastric pits in
gastric mucosa
• Gastric pits are
openings to
ducts into
which gastric
glands empty
their secretions
Exocrine gland
• Any gland that
directs its secretions
through a duct into
a compartment that
is contiguous with
the exterior of the
body
Cardiac
Pyloric
Fundic
Glandular
regions of
simple
stomach
Glandular regions of
equine, porcine and
ruminant stomachs
• Cardiac, fundic and
pyloric gland regions
are glandular
• Esophageal regions
(“E”) are nonglandular epithelium
Cardiac
Pyloric
Fundic
Cardiac
gland
region
(cardiac
mucosa)
Cardiac
Pyloric
Fundic
Fundic
gland
region
• Mucous
neck cells
• Parietal cells
• Chief cells
Fundic gland
region
• Mucous neck
cells secrete
mucus
• Parietal cells
secrete:
– HCl
– Intrinsic factor
(not in cats);
necessary for
absorption of
Vitamin B12
Fundic gland
region
• Chief cells
secrete
pepsinogen
– HCl converts
pepsinogen into
pepsin
– Pepsin is a
proteolytic
enzyme (breaks
down proteins
into peptides)
Cardiac
Pyloric
Fundic
Pyloric
gland
region
• Mucous
secreting
cells
• G cells
Pyloric gland
region
• G cells are endocrine
gland cells – secrete
the endocrine
hormone, gastrin
• Endocrine cells
secrete hormones into
the bloodstream –
travel to a distant part
of the body where
they produce an effect
on another cell type
Gastrin
may
interact
with
either
receptor
Substances that
stimulate HCl
secretion by
parietal cell
• Gastrin
• Acetylcholine
• Histamine
– Histamine secreted by
ECL cells in gastric
mucosa
Rennin
• Enzyme secreted by abomasal mucosa of
young ruminant
– Acts to coagulate milk protein, which facilitates its
digestion
Hormone secretions of small
intestine: cholecystokinin
Site of
secretion
Stimuli for
secretion
Primarily
duodenal
mucosa
•Inhibits gastric
Chyme with a:
emptying
•High amino
•↑ secretion of
acid
pancreatic enzymes
concentration
and HCO3•High fatty acid
•Stimulates gall
concentration
bladder contractions
•Low pH
Actions
Hormone secretions of the small
intestine: secretin
Site of secretion Stimuli for
secretion
Actions
Duodenal
mucosa
•↓ HCl
production in
stomach
•↑ pancreatic
HCO3- secretion
•↑ biliary HCO3secretion
Chyme with a:
•Low pH
•High fatty acid
concentration
Exocrine pancreatic secretions
• Liquid rich in
HCO3• Pancreatic
digestive
enzymes
• Both are
secreted into
duodenum
Pancreatic digestive enzymes
• Pancreatic
proteolytic
enzymes
(pancreatic
proteases) are
secreted as
proenzymes
(zymogens)
Activation of
pancreatic
proteases in
small intestine
• CCK stimulates
duodenal
mucosal cells to
produce
enteropeptidase
Proelastase
Elastase
Absorption of
amino acids from
small intestine