the equine digestive system ims #8895-a. objectives discuss internal organs discuss internal organs...
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ObjectivesObjectives
Discuss internal organsDiscuss internal organs
Identify the structures of the digestive Identify the structures of the digestive systemsystem
Recognize functions of the organs Recognize functions of the organs comprising the digestive system comprising the digestive system
Digestive SystemDigestive System
Monogastric - having one stomachMonogastric - having one stomach
Herbivores - plant-eating animals Herbivores - plant-eating animals
Digestive system anatomically developed Digestive system anatomically developed to continually digest small amount of food to continually digest small amount of food
Digestive SystemDigestive System
Eat simple-looking feeds containing Eat simple-looking feeds containing complex chemical substances complex chemical substances
dramatic changes during digestive process dramatic changes during digestive process before feed is used as energybefore feed is used as energy
Digestion - process of mechanical and Digestion - process of mechanical and chemical breakdown of feed into simple chemical breakdown of feed into simple structuresstructures
Digestive SystemDigestive System
Simple structures are:Simple structures are:solublesoluble (able to be dissolved) in water (able to be dissolved) in water
absorbed through absorbed through mucous membranesmucous membranes lining lining intestinal tractintestinal tract
membranes that line cavities in the body and membranes that line cavities in the body and connects inside of cavity to outsideconnects inside of cavity to outside
Digestive SystemDigestive System
Unique Unique
Small, efficient stomach for grain utilizationSmall, efficient stomach for grain utilization
Large cecum and colon for roughage Large cecum and colon for roughage utilizationutilization
Digestive SystemDigestive System
Purpose - process feed into component Purpose - process feed into component nutrients for:nutrients for:
AbsorptionAbsorption - process of taking in by various - process of taking in by various means means
UtilizationUtilization
Digestive SystemDigestive System
Alimentary canal (digestive system) - Alimentary canal (digestive system) - muscular hollow tube beginning at mouth muscular hollow tube beginning at mouth and ending at anus and ending at anus
Loops on itself many timesLoops on itself many times
Size - One inch in diameter at small Size - One inch in diameter at small intestine to eight inches at large colonintestine to eight inches at large colon
Digestive SystemDigestive SystemComponent parts include:Component parts include:MouthMouthPharynxPharynxEsophagusEsophagusStomachStomachSmall intestineSmall intestineLarge intestineLarge intestineRectumRectumAnusAnus
Digestive SystemDigestive System
Large intestine consists of the:Large intestine consists of the:
CecumCecumVentral and dorsal colonVentral and dorsal colonTransverse colonTransverse colonSmall colonSmall colonRectum Rectum
Digestive SystemDigestive System
Alimentary tract with help of teeth, tongue, Alimentary tract with help of teeth, tongue, salivary glands, liver, and pancreas salivary glands, liver, and pancreas prepare feed for absorption and eliminates prepare feed for absorption and eliminates wastewaste
Few feeds eaten are in simple forms ready Few feeds eaten are in simple forms ready to be absorbed and utilizedto be absorbed and utilized
Digestive SystemDigestive SystemMost feeds require substantial change by:Most feeds require substantial change by:Mechanical ActionMechanical Action
Secretory Action - products produced by Secretory Action - products produced by glands that aid in digestionglands that aid in digestion
Chemical ActionChemical Action
Microbial Action - digestion by very minute Microbial Action - digestion by very minute organismsorganisms
Digestive SystemDigestive System
Mechanical actions include:Mechanical actions include:Mastication – chewingMastication – chewing
Deglutition – swallowingDeglutition – swallowing
Intestinal movementsIntestinal movements
Defecation - elimination of wasteDefecation - elimination of waste
MouthMouth
First section of alimentary canalFirst section of alimentary canal
Contains 24 molars and 12 incisorsContains 24 molars and 12 incisors
Includes tongue and salivary glandsIncludes tongue and salivary glands
MouthMouth
Prehension -the grasping and moving of Prehension -the grasping and moving of feed into the mouth by a sensitive, mobile feed into the mouth by a sensitive, mobile upper lipupper lip
Precise - can graze grass almost into Precise - can graze grass almost into groundground
Sorts and selects haySorts and selects hay
MouthMouth
Digestion - begins in mouth when feed is Digestion - begins in mouth when feed is masticatedmasticated by the teeth by the teeth
grinded and chewed by the mouthgrinded and chewed by the mouth
Serves to reduce feed particle size Serves to reduce feed particle size
MouthMouth
Saliva:Saliva:85 pounds (10 gallons) daily85 pounds (10 gallons) daily
Wets feed - Easier to pass through Wets feed - Easier to pass through esophagusesophagus
Enzymes - help digest carbohydratesEnzymes - help digest carbohydrates
Produce large amounts only while chewingProduce large amounts only while chewing
PharynxPharynx
MuscularMuscular
Funnel shapeFunnel shape
Guides feed into esophagusGuides feed into esophagus
Located in upper back of mouth where Located in upper back of mouth where digestive and respiratory tracts crossdigestive and respiratory tracts cross
PharynxPharynx
Once feed or water enters pharynx, it Once feed or water enters pharynx, it cannot return because of blocking action cannot return because of blocking action of soft palateof soft palate
Epiglottis closes at the same time to Epiglottis closes at the same time to prevent feed from entering lungsprevent feed from entering lungs
EsophagusEsophagus
4 to 5 feet in length4 to 5 feet in length
Extends from mouth down left side of Extends from mouth down left side of neck, through the diaphragm, and to the neck, through the diaphragm, and to the stomachstomach
Moves feed and water to stomach by Moves feed and water to stomach by progressive waves of muscular progressive waves of muscular contractions called peristalsis contractions called peristalsis
EsophagusEsophagus
Waves irreversibleWaves irreversible
Extreme muscle tone occurs at end of Extreme muscle tone occurs at end of esophagusesophagus
EsophagusEsophagus
Extremely difficult to expel gases through Extremely difficult to expel gases through eructationeructation the act of expelling gas from the stomach the act of expelling gas from the stomach
through the mouththrough the mouth
Stomach would rupture before vomiting Stomach would rupture before vomiting would occurwould occur
StomachStomach
U-shaped sac near diaphragm at front of U-shaped sac near diaphragm at front of abdominal cavityabdominal cavity
Sphincter acts as powerful muscle where Sphincter acts as powerful muscle where esophagus enters into stomachesophagus enters into stomach
Makes vomiting nearly impossibleMakes vomiting nearly impossible
StomachStomach
Small compared to other animalsSmall compared to other animals
10% of total capacity of entire digestive 10% of total capacity of entire digestive tracttract
Capacity - two to four gallons Capacity - two to four gallons requires they eat two to three times daily requires they eat two to three times daily
rather than just oncerather than just once
StomachStomach
Feed moves through rapidlyFeed moves through rapidly
Frequent feeding in small amounts is more Frequent feeding in small amounts is more efficient and better satisfiesefficient and better satisfies
Rate of passageRate of passage is rapid in comparison to is rapid in comparison to other areasother areasTime required for something to move through Time required for something to move through
an areaan area
StomachStomach
Reservoir for ingested feed while Reservoir for ingested feed while subjecting it to subjecting it to gastric digestiongastric digestion chemical breakdown of feedstuffs by the chemical breakdown of feedstuffs by the
stomachstomach
Gastric juices, secreted by glands in the Gastric juices, secreted by glands in the mucous membrane of stomach, contain mucous membrane of stomach, contain hydrochloric acid, pepsin & gastric lipasehydrochloric acid, pepsin & gastric lipase
StomachStomach
Pepsin is a protease - enzyme that helps Pepsin is a protease - enzyme that helps digest protein into digest protein into amino acidsamino acidsbuilding blocks of proteinsbuilding blocks of proteins
Gastric lipase - digest fat into fatty acids & Gastric lipase - digest fat into fatty acids & glycerolglycerol
StomachStomach
When two-thirds full, feed passes into When two-thirds full, feed passes into small intestine and continues as eating small intestine and continues as eating continuescontinues
If horse eats too much at one time, some If horse eats too much at one time, some
will leave stomach without sufficient will leave stomach without sufficient digestive action digestive action Leads to decreased efficiency Leads to decreased efficiency
StomachStomach
Number of digestive disorders can occurNumber of digestive disorders can occur
Caused by:Caused by:moldy feedsmoldy feedsground mashesground mashessudden changes in feedsudden changes in feed feast-and-famine situationsfeast-and-famine situationsparasitesparasites
StomachStomach
Very little nutrient absorption takes place Very little nutrient absorption takes place in the stomachin the stomach
Proteins and carbohydrates are only Proteins and carbohydrates are only partially digestedpartially digested
Small IntestineSmall Intestine
2 inch by 60 foot tube2 inch by 60 foot tube
Holds approximately 12 gallonsHolds approximately 12 gallons
Connects stomach to large intestine Connects stomach to large intestine
Contains three parts: the duodenum, the Contains three parts: the duodenum, the jejunum, and the ileum jejunum, and the ileum
Small IntestineSmall Intestine
30% of the digestive tract30% of the digestive tract
Folded into many loops and coils Folded into many loops and coils
2.5 to 4 hours for feed to pass2.5 to 4 hours for feed to pass
Small IntestineSmall Intestine
BloodwormsBloodwormscause blood clots cause blood clots
may result in colic or deathmay result in colic or death
tend to lodge in the mesentery artery tend to lodge in the mesentery artery which supplies blood to the intestineswhich supplies blood to the intestines
Small IntestineSmall Intestine
Small intestine and accessory organs, the Small intestine and accessory organs, the pancreas and liver, supply enzymespancreas and liver, supply enzymes
Peristalsis mixes fluid contents of the Peristalsis mixes fluid contents of the
which are about 92-95% waterwhich are about 92-95% water
Pancreatic juices contain the enzymes Pancreatic juices contain the enzymes trypsin, pancreatic lipase, and amylasetrypsin, pancreatic lipase, and amylase
Small IntestineSmall Intestine
Trypsin - converts proteins into amino Trypsin - converts proteins into amino acids which the small intestine absorbsacids which the small intestine absorbs
Primary site of protein digestion and Primary site of protein digestion and absorption of amino acidsabsorption of amino acids
Pancreatic lipase - breaks down fats to Pancreatic lipase - breaks down fats to glycerol and fatty acids glycerol and fatty acids
Small IntestineSmall Intestine
Liver secretes bile Liver secretes bile helps break down fathelps break down fataids in fatty acid absorptionaids in fatty acid absorptionactivates pancreatic lipaseactivates pancreatic lipase
Most soluble carbohydrates digested in Most soluble carbohydrates digested in small intestinesmall intestine
Small IntestineSmall Intestine
End products of carbohydrate digestion End products of carbohydrate digestion are glucose and volatile fatty acids which are glucose and volatile fatty acids which are absorbed for energyare absorbed for energy
Absorbs nutrients, such as simple sugars, Absorbs nutrients, such as simple sugars, fatty acids, amino acids, minerals, and fatty acids, amino acids, minerals, and vitaminsvitamins
Large IntestineLarge Intestine
Composed of the cecum, large colon, Composed of the cecum, large colon, small colon, and rectumsmall colon, and rectum
Moves undigested materials from small Moves undigested materials from small intestine to anus for eliminationintestine to anus for elimination
50-60% of digestive tract50-60% of digestive tract
Large IntestineLarge Intestine
Holds 30-35 gallonsHolds 30-35 gallons
25 feet long25 feet long
Designed for utilization of plant fiber for Designed for utilization of plant fiber for energyenergy
Large IntestineLarge Intestine
After After ingestaingesta leaves small intestine, it leaves small intestine, it enters into cecumenters into cecumsubstances that have been taken into the substances that have been taken into the
body by way of the digestive tractbody by way of the digestive tract
Cecum serves as fermentation vat in Cecum serves as fermentation vat in
which enzymes break down fibrous plant which enzymes break down fibrous plant structures for digestionstructures for digestion
Large IntestineLarge IntestineCarbohydrates such as Carbohydrates such as cellulosecellulose that that
escaped digestion in small intestine are escaped digestion in small intestine are fermented in large intestinefermented in large intestine
Complex carbohydrate that is the main Complex carbohydrate that is the main component of the plant cell wallcomponent of the plant cell wall
Large IntestineLarge Intestine
Can digest cellulose, starch, & sugars into Can digest cellulose, starch, & sugars into volatile fatty acids volatile fatty acids
supplies up to 25% of horse’s energysupplies up to 25% of horse’s energy
Large IntestineLarge Intestine
Cecum - primary site of water absorptionCecum - primary site of water absorption
Rate of passage slower than in other Rate of passage slower than in other portions of digestive tractportions of digestive tract
36-48 hours36-48 hours
RectumRectum
Connects small colon to anusConnects small colon to anus
Receives feces small colon has formed Receives feces small colon has formed into characteristic ballsinto characteristic balls
Forty to fifty pounds of feces is voided Forty to fifty pounds of feces is voided eight to twelve times a dayeight to twelve times a day
RectumRectum
Shape, size, and consistency of feces give Shape, size, and consistency of feces give clues to overall healthclues to overall health
Dry and hard - lack of water or proteinDry and hard - lack of water or protein
Too soft - Sick or eating diet that is too Too soft - Sick or eating diet that is too laxative laxative
DisordersDisorders
Because of the complex nature of the Because of the complex nature of the digestive system, horses are predisposed digestive system, horses are predisposed to digestive disordersto digestive disorders
Susceptible to twisting and impaction of Susceptible to twisting and impaction of the large intestinethe large intestine
DisordersDisorders
Sensitive to gases produced by microbial Sensitive to gases produced by microbial digestiondigestion
Rapid fermentation may cause excessive Rapid fermentation may cause excessive gas or lactic acid to be producedgas or lactic acid to be produced
can cause colic or laminitiscan cause colic or laminitis
ColicColic
““Colic” - many painful digestive Colic” - many painful digestive disturbances with various causesdisturbances with various causes
Improper feeding such as feeding too Improper feeding such as feeding too much grain or suddenly changing the diet much grain or suddenly changing the diet can cause coliccan cause colic
ColicColic
Usually caused by gaseous products that Usually caused by gaseous products that are part of microbial digestionsare part of microbial digestions
May cause swelling in digestive tractMay cause swelling in digestive tract
Ingesting low quality, poorly digestible Ingesting low quality, poorly digestible feed can cause impaction of cecum and feed can cause impaction of cecum and colon colon
ColicColic
To avoid digestive disturbances, allow one To avoid digestive disturbances, allow one to two weeks to change from one feed to to two weeks to change from one feed to another.another.
LaminitisLaminitis
Occurs when inner hoof wall becomes Occurs when inner hoof wall becomes inflamedinflamed
Rapid changes in diet can cause certain Rapid changes in diet can cause certain type of bacteria in cecum to dietype of bacteria in cecum to die
Release large amounts of endotoxins Release large amounts of endotoxins
LaminitisLaminitis
Endotoxins enter bloodstream and Endotoxins enter bloodstream and decrease the amount of blood flow to decrease the amount of blood flow to laminalamina
Commonly occurs when a horse is Commonly occurs when a horse is switched from winter hay to pasture in the switched from winter hay to pasture in the spring spring
SummarySummary
Purpose of digestive system is to process Purpose of digestive system is to process feed into component nutrients for feed into component nutrients for absorption and utilization by the bodyabsorption and utilization by the body
Very complexVery complex
Many digestive disordersMany digestive disorders
SummarySummary
MonogastricMonogastric
Eat relatively simple-looking foods that are Eat relatively simple-looking foods that are transformed to an easily digestible formtransformed to an easily digestible form