Comparative anatomy
( Chordates)
Digestive system
1-Human
2-Ruminant
3-Avian
4-Horse
5-Fish
Dr.Omer
Digestive System
Introduction
• Three (3) basic types of digestive systems according
to their stomachs :
►Monogastric – simple stomach.
►Ruminant (cranial fermentor) – multi-compartmented
stomachs.
►Hind gut (caudal) fermentor – simple stomach, but very
large and complex large intestine
Types of Digestive Systems
Cats
Chickens Pigs
DogsTurkeys
Monogastrics Ruminants
Hind Gut
Fermentors
Beef Cattle Dairy Cattle
Deer
SheepGoats
Horses
Rabbits
Ostrich
Types of Digestive Systems
• Are divided into three groups based on their
food sources
1. Herbivores are animals that eat plants
exclusively
2. Carnivores are animals that eat other animals
3. Omnivores are animals that eat both plants and
other animals
5
Carnivore
• Eat primarily
other animals.
Herbivore
• Eat primarily
plant materials.
omnivore
• Eat combination
of plant and
animal material.
The Human Digestive System
Human
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Primates
Family Hominidae
Genus Homo
Species sapiens
Introduction
• The digestive system is used for breaking down food
into nutrients which then pass into the circulatory
system and are taken to where they are needed in the
body.
Main Functions of Digestive Tract
• The major activities of GI tract
• 1-Ingestion: taking in food
2.Motility
• Propel ingested food from mouth toward rectum
3.Secretion of juices e.g. saliva
• Aid in digestion and absorption
4.Digestion
• Food broken down into absorbable molecules
5.Absorption
• Nutrients, electrolytes, and water are absorbed or transported
from lumen of GIT to blood stream
6.. Egestion (Elimination) : removing any leftover wastes
Digestion
• Types
– Mechanical (physical)
• Chew
• Tear
• Grind
• Mash
• Mix
– Chemical
• Enzymatic reactions to improve digestion of
– Carbohydrates
– Proteins
– Lipids
Anatomy of the Digestive Tract
GIT consists of;
– Oral cavity or mouth
– Pharynx
– Esophagus
– Stomach
– Small intestine
– Large intestine
– Rectum
– Anus
Mouth or oral cavity
• Ingestion - bringing food into the body
– tongue - taste buds detect chemical composition of food
• Mastication - chewing (physical digestion)
– teeth and tongue
• Chemical digestion - saliva
– moistens food
– amylase - breaks down starch
– lysozyme - antibacterial agent
Mouth and Teeth
Esophagus
• Muscular tube connecting the pharynx to the stomach.
• Functions include:
1. Secretes mucus
2. Moves food from the throat to the stomach using
muscle movement called peristalsis
 Cardiac Sphincter – connects esophagus and stomach
• If acid from the stomach gets in here that’s heartburn.
17
Stomach
• Muscular sac-like organ
• Chemical and physical digestion
– forms chyme
• goblet cells – mucus
– forms a protective barrier against the high acidity of the
stomach content.
– parietal cells – HCl
– kills bacteria, denatures proteins
• chief cells - pepsinogen
– pepsinogen activated by HCl  pepsin
– pepsin breaks down proteins
19
The Stomach
Small intestine
Functions
Digestion
Digest carbohydrates : amylase from pancreas
Digest proteins : trypsin & chymotrypsin from pancreas
Digest lipids (fats) bile from liver & lipase from pancreas
Absorption
VILLI – small finger-like projections that increase the surface area
MICROVILLI – even smaller finger-like projections on the VILLI
LACTEAL – large lymph vessel found on each villus (Absorbs FAT)
Capillaries – small blood vessels found on each villus (Absorbs all
nutrients EXCEPT Fat)
The Parts of Small intestine
1. Duodenum - most digestion occurs here
2. Jejunum - some digestion and some
absorption occur
3. Ileum - mostly absorption
SMALL INTESTINE
• The small
intestine is divided
• duodenum
• jejunum
• ileum.
• Pancreas has 2 functions:
a) Endocrine functions: secretes insulin and glucagon from islets of
Langerhans
b) Exocrine function: secretion of pancreatic juice
• It has 2 components: aqueous and enzymatic components.
• Aqueous component (contains HCO3) is important for neutralizing
stomach acid in the duodenum so pancreatic enzymes can function
properly
• Enzymatic component is essential for the proper digestion and
absorption of carbohydrates, fats, and proteins
• Pancreatic enzymes include trypsin, chemotrypsin, lipase, and
amylase
Functions of the Pancreas
24
Liver
Functions of the Liver:
1) Metabolic regulation
• Store absorbed nutrients, vitamins
• Release nutrients as needed
2) Hematological regulation
• Plasma protein production
• Remove old RBCs
3) Production of bile
• Required for fat digestion and absorption
Liver
Liver
The Large Intestine (colon)
• Much shorter than small intestine, but has larger
diameter
Functions
1. Goblet cells: create mucus that lubricates colon and
protects mucosa.
2. Absortive cells: Maintain water balance, solidify
feces, absorb vitamins and some ions
• Prepare waste for expulsion
28
29
Digestive System
– Ruminants –
Mouth, esophagus, liver, pancreas, gall bladder,
small intestine, and large intestine have functions
similar to monogastrics.
Cow
•
• Kingdom Animal
• Phylum Chordata
• Class Mammalia
• Order Artiodactyla
• Family Bovidae
• Genus Bos
• Species indicus Asian humped cattle
taurus European non-humped cattle
Reticulum
• Holding area for feed after it passes down esophagus.
• Provides additional area for fermentation.
• Contains microorganisms, like rumen
• Collection compartment for foreign objects.
• Helps open and close rumen.
• Minimal separation with rumen.
“honeycomb”
Rumen
• Largest of the four components.
• On the left side of the animal.
• Storage site and fermentation .
• Houses millions of microorganisms.
• Lined with millions of finger-like projections (papillae) that are
needed for absorption.
“paunch”
Omasum
• A heavy, hard organ that has many folds or leaves.
• Little, if any digestive activity.
• Grinds feed particles.
• Removes moisture.
“many piles”
Abomasum
• True, glandular stomach
• Functions similarly to monogastric stomach
• Secretes gastric juices which aid in digestion.
Infected with barber pole worms
Organs of the Digestive System
– Hind Gut Fermentors –
Mouth, esophagus, stomach, liver, pancreas,,
and small intestine have similar functions as
compared to monogastrics.
Horse doesn’t have gall bladder
Digestive Tract
- Horse-
Esophagus
Stomach
Duodenum
Small
intestineCecum
Large
colon
Small colon
Rectum
Organs of the Digestive System
– Hind Gut Fermentors –
• Large Intestine
► Major difference between monogastrics and hind gut fermentors is the
large intestine.
► Large intestine is exceptionally large and complex compared to
monogastrics and ruminants.
The large intestine of hind gut fermentors is analogous to the rumen in
ruminants.
► Microbes digest structural carbohydrates (cellulose, hemicellulose) and
soluble carbohydrates that escape digestion in small intestine to VFA’s.
 VFA’s absorbed from large intestine and utilized by the animal.
► Microbial protein produced in large intestine is wasted (only very limited
absorption from large intestine).
Avian Digestive System
Avian Digestive Systems
• Mouth
– no teeth
– Salivation excretion moistens food
• Esophagus
– has a modification called the “crop” which stores
and moistens food
– connects mouth and stomach
Avian Digestive Systems
• Stomach
– Contains two parts
• Proventriculus: same as monogastric stomach and
provides digestive excretions
• Gizzard: located after proventriculus, very muscular,
used to grind food
Avian Digestive Systems
• Small Intestine
– similar functions as in ruminants and monogastric
systems
• Large Intestine
– similar functions as in ruminants and monogastric
systems
– “cloaca”: chamber into which urinary and genital
canals open
– “ceca”: aids in fiber digestion and absorption
Digestive System Comparisons
Function Monogastric Ruminants
Hind Gut
Fermentors
Digest and extract
energy from cellulose
Very limited
(large intestine)
Yes
(rumen/reticulum)
Yes
(large intestine)
Utilize dietary sugar
sources directly
Yes
(absorbed as glucose)
No
(fermented to VFA’s)
Yes
(absorbed as glucose)
Utilize protein from
feeds directly
Yes Limited
(most converted to microbial
protein)
Yes
Utilize fat from feeds
directly
Yes Some
(most fermented to VFA’s)
Yes
Utilize microbial
protein
No Yes
(60-80% of AA from microbes)
No
Human Cattle Bird Horses
Teeth 32 32 0 40-42
Organs of digestive system Comparisons
Ruminant
• Mouth
• Esophagus
• Stomach
– Reticulum
– Rumen
– Omasum
– Abomasum
• Small intestines
• Large intestines
Monogastric
• Mouth
• Esophagus
• Stomach
• Small intestines
• Large intestines
Liver
Pancreas
Liver
Pancreas
Thank you

Comparative anatomy digestive system

  • 1.
    Comparative anatomy ( Chordates) Digestivesystem 1-Human 2-Ruminant 3-Avian 4-Horse 5-Fish Dr.Omer
  • 2.
  • 3.
    Introduction • Three (3)basic types of digestive systems according to their stomachs : ►Monogastric – simple stomach. ►Ruminant (cranial fermentor) – multi-compartmented stomachs. ►Hind gut (caudal) fermentor – simple stomach, but very large and complex large intestine
  • 4.
    Types of DigestiveSystems Cats Chickens Pigs DogsTurkeys Monogastrics Ruminants Hind Gut Fermentors Beef Cattle Dairy Cattle Deer SheepGoats Horses Rabbits Ostrich
  • 5.
    Types of DigestiveSystems • Are divided into three groups based on their food sources 1. Herbivores are animals that eat plants exclusively 2. Carnivores are animals that eat other animals 3. Omnivores are animals that eat both plants and other animals 5
  • 6.
    Carnivore • Eat primarily otheranimals. Herbivore • Eat primarily plant materials. omnivore • Eat combination of plant and animal material.
  • 7.
  • 8.
    Human Kingdom Animalia Phylum Chordata ClassMammalia Order Primates Family Hominidae Genus Homo Species sapiens
  • 9.
    Introduction • The digestivesystem is used for breaking down food into nutrients which then pass into the circulatory system and are taken to where they are needed in the body.
  • 10.
    Main Functions ofDigestive Tract • The major activities of GI tract • 1-Ingestion: taking in food 2.Motility • Propel ingested food from mouth toward rectum 3.Secretion of juices e.g. saliva • Aid in digestion and absorption 4.Digestion • Food broken down into absorbable molecules 5.Absorption • Nutrients, electrolytes, and water are absorbed or transported from lumen of GIT to blood stream 6.. Egestion (Elimination) : removing any leftover wastes
  • 12.
    Digestion • Types – Mechanical(physical) • Chew • Tear • Grind • Mash • Mix – Chemical • Enzymatic reactions to improve digestion of – Carbohydrates – Proteins – Lipids
  • 13.
    Anatomy of theDigestive Tract GIT consists of; – Oral cavity or mouth – Pharynx – Esophagus – Stomach – Small intestine – Large intestine – Rectum – Anus
  • 14.
    Mouth or oralcavity • Ingestion - bringing food into the body – tongue - taste buds detect chemical composition of food • Mastication - chewing (physical digestion) – teeth and tongue • Chemical digestion - saliva – moistens food – amylase - breaks down starch – lysozyme - antibacterial agent
  • 15.
  • 16.
    Esophagus • Muscular tubeconnecting the pharynx to the stomach. • Functions include: 1. Secretes mucus 2. Moves food from the throat to the stomach using muscle movement called peristalsis  Cardiac Sphincter – connects esophagus and stomach • If acid from the stomach gets in here that’s heartburn.
  • 17.
  • 18.
    Stomach • Muscular sac-likeorgan • Chemical and physical digestion – forms chyme • goblet cells – mucus – forms a protective barrier against the high acidity of the stomach content. – parietal cells – HCl – kills bacteria, denatures proteins • chief cells - pepsinogen – pepsinogen activated by HCl  pepsin – pepsin breaks down proteins
  • 19.
  • 20.
    Small intestine Functions Digestion Digest carbohydrates: amylase from pancreas Digest proteins : trypsin & chymotrypsin from pancreas Digest lipids (fats) bile from liver & lipase from pancreas Absorption VILLI – small finger-like projections that increase the surface area MICROVILLI – even smaller finger-like projections on the VILLI LACTEAL – large lymph vessel found on each villus (Absorbs FAT) Capillaries – small blood vessels found on each villus (Absorbs all nutrients EXCEPT Fat)
  • 21.
    The Parts ofSmall intestine 1. Duodenum - most digestion occurs here 2. Jejunum - some digestion and some absorption occur 3. Ileum - mostly absorption
  • 22.
    SMALL INTESTINE • Thesmall intestine is divided • duodenum • jejunum • ileum.
  • 23.
    • Pancreas has2 functions: a) Endocrine functions: secretes insulin and glucagon from islets of Langerhans b) Exocrine function: secretion of pancreatic juice • It has 2 components: aqueous and enzymatic components. • Aqueous component (contains HCO3) is important for neutralizing stomach acid in the duodenum so pancreatic enzymes can function properly • Enzymatic component is essential for the proper digestion and absorption of carbohydrates, fats, and proteins • Pancreatic enzymes include trypsin, chemotrypsin, lipase, and amylase Functions of the Pancreas
  • 24.
  • 25.
    Liver Functions of theLiver: 1) Metabolic regulation • Store absorbed nutrients, vitamins • Release nutrients as needed 2) Hematological regulation • Plasma protein production • Remove old RBCs 3) Production of bile • Required for fat digestion and absorption
  • 26.
  • 27.
  • 28.
    The Large Intestine(colon) • Much shorter than small intestine, but has larger diameter Functions 1. Goblet cells: create mucus that lubricates colon and protects mucosa. 2. Absortive cells: Maintain water balance, solidify feces, absorb vitamins and some ions • Prepare waste for expulsion 28
  • 29.
  • 31.
    Digestive System – Ruminants– Mouth, esophagus, liver, pancreas, gall bladder, small intestine, and large intestine have functions similar to monogastrics.
  • 32.
    Cow • • Kingdom Animal •Phylum Chordata • Class Mammalia • Order Artiodactyla • Family Bovidae • Genus Bos • Species indicus Asian humped cattle taurus European non-humped cattle
  • 34.
    Reticulum • Holding areafor feed after it passes down esophagus. • Provides additional area for fermentation. • Contains microorganisms, like rumen • Collection compartment for foreign objects. • Helps open and close rumen. • Minimal separation with rumen. “honeycomb”
  • 35.
    Rumen • Largest ofthe four components. • On the left side of the animal. • Storage site and fermentation . • Houses millions of microorganisms. • Lined with millions of finger-like projections (papillae) that are needed for absorption. “paunch”
  • 36.
    Omasum • A heavy,hard organ that has many folds or leaves. • Little, if any digestive activity. • Grinds feed particles. • Removes moisture. “many piles”
  • 37.
    Abomasum • True, glandularstomach • Functions similarly to monogastric stomach • Secretes gastric juices which aid in digestion. Infected with barber pole worms
  • 38.
    Organs of theDigestive System – Hind Gut Fermentors – Mouth, esophagus, stomach, liver, pancreas,, and small intestine have similar functions as compared to monogastrics. Horse doesn’t have gall bladder
  • 41.
  • 42.
    Organs of theDigestive System – Hind Gut Fermentors – • Large Intestine ► Major difference between monogastrics and hind gut fermentors is the large intestine. ► Large intestine is exceptionally large and complex compared to monogastrics and ruminants. The large intestine of hind gut fermentors is analogous to the rumen in ruminants. ► Microbes digest structural carbohydrates (cellulose, hemicellulose) and soluble carbohydrates that escape digestion in small intestine to VFA’s.  VFA’s absorbed from large intestine and utilized by the animal. ► Microbial protein produced in large intestine is wasted (only very limited absorption from large intestine).
  • 43.
  • 45.
    Avian Digestive Systems •Mouth – no teeth – Salivation excretion moistens food • Esophagus – has a modification called the “crop” which stores and moistens food – connects mouth and stomach
  • 46.
    Avian Digestive Systems •Stomach – Contains two parts • Proventriculus: same as monogastric stomach and provides digestive excretions • Gizzard: located after proventriculus, very muscular, used to grind food
  • 47.
    Avian Digestive Systems •Small Intestine – similar functions as in ruminants and monogastric systems • Large Intestine – similar functions as in ruminants and monogastric systems – “cloaca”: chamber into which urinary and genital canals open – “ceca”: aids in fiber digestion and absorption
  • 49.
    Digestive System Comparisons FunctionMonogastric Ruminants Hind Gut Fermentors Digest and extract energy from cellulose Very limited (large intestine) Yes (rumen/reticulum) Yes (large intestine) Utilize dietary sugar sources directly Yes (absorbed as glucose) No (fermented to VFA’s) Yes (absorbed as glucose) Utilize protein from feeds directly Yes Limited (most converted to microbial protein) Yes Utilize fat from feeds directly Yes Some (most fermented to VFA’s) Yes Utilize microbial protein No Yes (60-80% of AA from microbes) No
  • 51.
    Human Cattle BirdHorses Teeth 32 32 0 40-42
  • 52.
    Organs of digestivesystem Comparisons Ruminant • Mouth • Esophagus • Stomach – Reticulum – Rumen – Omasum – Abomasum • Small intestines • Large intestines Monogastric • Mouth • Esophagus • Stomach • Small intestines • Large intestines Liver Pancreas Liver Pancreas
  • 53.