490407
Description
Mind Map by Lydia Buckmaster, updated more than 1 year ago
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Created by Lydia Buckmaster
almost 11 years ago
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Equine Digestive Physiology
- Equus caballus
- Trickle feeding
plains animal
- Feeds for around
16 hours per day
- 8 hours spent
sleeping, moving
and playing
- Feeds for around
16 hours per day
- Herbivore
- Hind gut
fermenter with
a large caecum
- Ferments
large quantities
of fibre
- Ferments
large quantities
of fibre
- Hind gut
fermenter with
a large caecum
- Trickle feeding
plains animal
- Mouth
- Teeth
- Hipsodonts
- Teeth are
continually
growing
- Diet is
high in
silica
- Hard substance
which wears
away the teeth
- Hard substance
which wears
away the teeth
- If a tooth is lost, the one
above or below continues
to grow into the space
and gum, stopping the
horse from chewing
- Diet is
high in
silica
- Teeth are
continually
growing
- Large molars
- Large
grinding
surface
- Large
grinding
surface
- Maxilla (top jaw)
- Stays still
during
chewing
- Stays still
during
chewing
- Mandible (bottom jaw)
- Moves side to
side as well as
back to front
- Allows the
horse to chew
in different
directions
- Allows the
horse to chew
in different
directions
- Moves side to
side as well as
back to front
- Hipsodonts
- 3 pairs of salivary
glands that buffer
acid in the stomach
- Also lubricating to
prevent damage to the
oesophagus when
swallowing dry food
- Also lubricating to
prevent damage to the
oesophagus when
swallowing dry food
- Split into
quarters
- Top left,
top right,
bottom left,
bottom right
- Each quarter
has 3 molars, 3
premolars and
3 incisors
- Vestidual canines
mainly found in
males and are
often removed
- Vestidual canines
mainly found in
males and are
often removed
- Each quarter
has 3 molars, 3
premolars and
3 incisors
- Top left,
top right,
bottom left,
bottom right
- Teeth
- Stomach
- Amylase
- In the
stomach
- Buffers acid (as a
bicarbonate) and
acts as a lubricant
to aid movement
- In the
stomach
- Four sections
- Oesophageal
- Bottom of the
oesophagus and the
top of the stomach
- Squamous
tissue
- No secretions
- No secretions
- Lots of
bacteria
- Lactobacilli
- Streptococcus
- Small amount
of bacterial
fermentation of
food
- Lactobacilli
- Bottom of the
oesophagus and the
top of the stomach
- Cardiac
- Glandular
tissue
- Secretes
mucous
- Coats and protects
the stomach,
preventing acidic
digestion of the
stomach wall
- Coats and protects
the stomach,
preventing acidic
digestion of the
stomach wall
- Secretes
mucous
- Glandular
tissue
- Fundic
- Glandular
tissue
- Secretes HCl
- Digestion
- Digestion
- Secretes
Pepsinogen
- Tail cleaved
off in acidic
conditions,
giving pepsin
- This is an enzyme
which breaks down
proteins into peptides
- This is an enzyme
which breaks down
proteins into peptides
- Tail cleaved
off in acidic
conditions,
giving pepsin
- Secretes HCl
- Glandular
tissue
- Pyloric
- Glandular
tissue
- Secretes
Gastrin
- Upon gut fill, enzyme
is released into the
blood, inducing the
satiety response
- Upon gut fill, enzyme
is released into the
blood, inducing the
satiety response
- Secretes
Gastrin
- Glandular
tissue
- Oesophageal
- Contents undergo
mechanical and
chemical (acidic)
digestion
- Amylase
- Equine Gastric Ulcer
Syndrome (EGUS)
- Focal (or multi focal)
ulceration of the
stomach epithelium
- Estimated 74% of horses
in training are affected
(Habershon-Butcher et
al., 2012)
- Likely due to lack
of fibre (no grass
or haylage), lots of
unprocessed grain
and lots of fast
exercise
- During fast exercise, the
horse experiences transient
deceleration as the legs
move, which can cause the
contents of the acidic regions
of the stomach to move into
the poorly protected
oesophageal region
- During fast exercise, the
horse experiences transient
deceleration as the legs
move, which can cause the
contents of the acidic regions
of the stomach to move into
the poorly protected
oesophageal region
- Estimated 74% of horses
in training are affected
(Habershon-Butcher et
al., 2012)
- Symptoms
- Loss in
appetite
- Weight
loss
- Weight
loss
- Lethargy
- Poor
performance
- Poor
performance
- Colic
- Dull
coat
- Loss in
appetite
- Diagnosis
- Endoscope
- Endoscope
- Treatment
- Tendency to
treat symptoms
as it is cheaper
- Reducing acid
production
- Not effective
as an acidic
environment
in its stomach
- Antacids bring up the
pH, but buffering it
denatures enzymes
and affects the
microbial population
- Omeprazole
- Proton-pump
inhibitor which
prevents HCl
secretion
- Metabolised
in the liver and
well excreted
- Well absorbed in
acidic conditions,
that it gets rid of as
it goes along
- 77% healing
after 28 days
- Proton-pump
inhibitor which
prevents HCl
secretion
- Not effective
as an acidic
environment
in its stomach
- Tendency to
treat symptoms
as it is cheaper
- Focal (or multi focal)
ulceration of the
stomach epithelium
- Small Intestine
- Highly specialised
for digestion and
absorption
- Duodenum
- Low pH in the
stomach and
duodenum
- Causes secretin
to be released
from the crypts
of Leiberkuhn
- Stimulates the
pancreas and
inhibits gastrin
release
- Cholecystokinin (CKK) is
released when food reaches
the small intestine,
stimulating the release of
pancreatic fluid and bile,
inducing a satiety effect
- Cholecystokinin (CKK) is
released when food reaches
the small intestine,
stimulating the release of
pancreatic fluid and bile,
inducing a satiety effect
- Stimulates the
pancreas and
inhibits gastrin
release
- Causes secretin
to be released
from the crypts
of Leiberkuhn
- Pancreas is
found in the
first loop of
the duodenum
- Linked
via the
pancreatic
duct
- Secretions
- Both endocrine and
exocrine, and
secretes digestive
enzymes into the
duodenum
- Insulin, glucagon
and pancreatic
fluid into the lumen
of the small
intestine
- Trypsin and
Chymotrypsin
to continue
protein
digestion
- Pancreatic
amylase
converts
starch to
maltose
- Pancreatic lipase
hydrolyses fat
- Both endocrine and
exocrine, and
secretes digestive
enzymes into the
duodenum
- Linked
via the
pancreatic
duct
- Low pH in the
stomach and
duodenum
- Jejunum
- Ileum
- Site of enzymatic
digestion and
absorption, an the
pancreatic and bile
ducts empty into it
- The wall of the
intestine is comprised
of goblet cells with villi
and microvilli, which
increase the surface
area for absorption
- Liver
- Site of conversion
for glucose to
glycogen, and also
a site of storage
- Secretes bile,
detoxifies toxins
and poisons and
breaks down uric
acid to form urea
- Hepatocytes
secrete the bile
- 94% is
reabsorbed
into the liver
and reused
- 94% is
reabsorbed
into the liver
and reused
- Horses do not
have a gall bladder,
so bile is secreted
straight into the
small intestine
- Bile acids
emulsify lipids so
that they can be
absorbed easily
- Hepatocytes
secrete the bile
- Site of conversion
for glucose to
glycogen, and also
a site of storage
- Carbs, fats and proteins are
efficiently digested and
products absorbed. The extent
of digestion depends on transit
time, which depends on diet
and exercise. It has a neutral
pH, and secretions from the
pancreas and liver are involved
- Highly specialised
for digestion and
absorption
- Large
Intestine
- Compartmentalised, with
sections separated by
valves such as the
ileocaecal valve and
caeco-ventral colonic valve
- Huge
amount
of mixing
- Tight areas are
susceptible to
colic, especially
the pelvic flexure
- Pelvic flexure is a
valve which prevents
large particle from
continuing, ensuring
that they are fermented
before continuing
- Pelvic flexure is a
valve which prevents
large particle from
continuing, ensuring
that they are fermented
before continuing
- Malfermentation
- Due to lack
of forage
- Worms
- Red worms
migrate through
the intestinal
wall, causing
blood clots and
killing the tissue
- Tapeworms
cause localised
infection
- Red worms
migrate through
the intestinal
wall, causing
blood clots and
killing the tissue
- Due to lack
of forage
- Huge
amount
of mixing
- Entrance to the caecum
occurs when the stomach
distends and food enters
- Neural
gastro-ileal
reflex
- Neural
gastro-ileal
reflex
- Retention time
- Longer fibre
spends longer
in the large
intestine
- As feeding
frequency
increases, time
spent in the large
intestine decreases
- Markers such as
titanium dioxide can
be used to measure
retention time, as they
are indigestible and so
pass straight through
- Have to be
associated
with food
- Have to be
associated
with food
- Longer fibre
spends longer
in the large
intestine
- Microflora
- Secrete cellulases,
and synthesise
vitamins and essential
amino acids
- Cellulases break down
cellulose into glucose, as
well as breaking down
hemicellulose
- Cellulases break down
cellulose into glucose, as
well as breaking down
hemicellulose
- Secrete cellulases,
and synthesise
vitamins and essential
amino acids
- Compartmentalised, with
sections separated by
valves such as the
ileocaecal valve and
caeco-ventral colonic valve
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